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  • 301.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Bright, Jamie M
    Australian National University.
    Engerer, Nicholas A
    Australian National University.
    Ahlberg, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Killinger, Sven
    Australian National University.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Comparing the capability of low- and high-resolution LiDAR data with application to solar resource assessment, roof type classification and shading analysis2017Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 205, s. 1216-1230Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    LiDAR (Light Detection and Ranging) data have recently gained popularity for use in solar resource assessment and solar photovoltaics (PV) suitability studies in the built environment due to robustness at identifying building orientation, roof tilt and shading. There is a disparity in the geographic coverage of low- and high-resolution LiDAR data (LL and LH, respectively) between rural and urban locations, as the cost of the latter is often not justified for rural areas where high PV penetrations often pose the greatest impact on the electricity distribution network. There is a need for a comparison of the different resolutions to assess capability of LL. In this study, we evaluated and improved upon a previously reported methodology that derives roof types from a LiDAR-derived, low-resolution Digital Surface Model (DSM) with a co-classing routine. Key improvements to the methodology include: co-classing routine adapted for raw LiDAR data, applicability to differing building type distribution in study area, building height and symmetry considerations, a vector-based shading analysis of building surfaces and the addition of solar resource assessment capability.

    Based on the performance of different LiDAR resolutions within the developed model, a comparison between LL (0.5-1 pts/m(2)) and LH (6-8 pts/m(2)) LiDAR data was applied; LH can confidently be used to evaluate the applicability of LL, due to its significantly higher point density and therefore accuracy. We find that the co-classing methodology works satisfactory for LL for all types of building distributions. Roof-type identification errors from incorrect co-classing were rare (< 1%) with LL. Co-classing buildings using LL improves accuracy of roof-type identification in areas with homogeneous distribution of buildings, here from 78% to 86% in accuracy. Contrastingly, co-classing accuracy using LH is marginally reduced for all building distributions from 94.8% to 94.4%. We adapt the Hay and Davies solar transposition model to include shading. The shading analysis demonstrates similarity of results between LL and LH. We find that the proposed methodology can confidently be used for solar resource assessments on buildings when only LiDAR data of low-resolution (< 1 pts/m(2)) is available.

  • 302.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Hallqvist, Rebecca
    Volotinen, Tarja
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lighting Performance and Energy Saving of a Novel Fibre Optic Lighting System2013Inngår i: Proceedings of CISBAT 2013 - International Conference - Cleantech for Sustainable Buildings, 2013, s. 317-322Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The abundant luminous ux of 3000 - 4600 lm at 100 000 - 130 000 lx direct sun illuminanceat a 10 m ber distance was obtained from Parans ber optic solar lighting system SP3.The illuminance of 2400 lm at 100 000 lx, after a 20 m distance, was higher than specied.The illumination performance and energy savings of a solar ber optic lighting system havebeen veried in a study hall - corridor interior within the EU FP7 NMP project Clear-upat Uppsala University in Sweden. The system provides the intensive full spectrum whitelight with the color temperature (that describes the light color perceived) being 5800 300 K, i.e. close to the direct sunlight outside. The color rendering index (85) (thatdescribes how well colors are rendered under the light source) is higher for the solar lightsthan for the supplementary uorescent lights (77). Thus this high quality solar lightingimproves the visibility of all kinds of objects compared to the uorescent lights. Annuallighting energy savings of 19 % in Uppsala, Sweden and 46 % in southern Europe wereestimated for a study hall interior, as well as 27 % and 55 % respectively for an interiorilluminated 16 h per day all days of a year. The ecacy (the total output ux divided bythe consumed electric energy) of 300 lm/W was obtained at sun illuminance over 100 000lx is signicantly higher than for any articial light sources available. Furthermore, thespatial light distribution was noticed to be wider than the expected, and a new .ldt-le wasdeveloped from the data for lighting simulation tools. The illuminance distributions werestudied in the study hall under various sunlight conditions and the experimental data wasfound to correspond to the simulated light scenes. This solar lighting technology wouldhave the greatest impact in oces and other commercial environments where humanbeings would work under these lights.

  • 303.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Killinger, Sven
    Australian National University.
    Engerer, Nicholas A
    Australian National University.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Bright, Jamie M
    Australian National University.
    Identification of PV system shading using a LiDAR-based solar resource assessment model: an evaluation and cross-validation2018Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 159, s. 157-172Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photovoltaic (PV) systems are subject to several different systematic de-rating factors, such as soiling, degradation, inverter mismatch and shading. With increasing penetration of PV in the local grid, Distribution Network Service Providers (DNSPs) are inclined to assess such losses, in order to accurately estimate the total regional power output of distributed PV. The most influential de-rating factor is shading, which can cause ramps on the generated power output, similar to clouds. In this study we evaluate and compare two fundamentally different methods for module orientation parametrisation and shading analysis of PV systems that have been developed in previous work. In the first method, LiDAR (Light Detection and Ranging) data are used to derive the PV module orientation and shading, referred to herein as LiDAR model. The second method, referred to as the QCPV-Tuning model, is based on reported PV power generation, which is firstly quality controlled and parametrised in order to derive module orientation and a loss factor, LF, representing systematic de-rating factors. Secondly, variations in de-ratings throughout the day, mainly due to shading, are explored in a process referred to as Tuning. For both methods, binary time series are derived expressing the presence of shading, which are used to evaluate how the methods corroborate. We evaluate four cases; case 1) evaluates the original versions of the LiDAR and QCPV-Tuning models, while in case 2-4 improvements to the models are introduced. A new filter for extracting representative LiDAR data points for the shading analysis was introduced for the LiDAR model (case 2). For the QCPV-Tuning model significant inaccuracies in the parametrisation of the module orientation were identified due to strong shading in either morning or evening and were thus corrected to observed parameters (case 3). For case 4) improvements on both models were introduced. The Pearson correlation coefficients of shading events for the methods were 0.28, 0.36, 0.42 and 0.50 for case 1-4, respectively. A mismatch in the timing of shading events motivated the comparison of the mean hourly shading, with correlation coefficients of 0.34, 0.43, 0.49 and 0.57 for case 1-4, respectively. The results of this study show that both methods can confidently be used for solar resource assessment, given the suggested improvements.

  • 304.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Marklund, Jesper
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Maximizing PV hosting capacity by smart allocation of PV: A case study on a Swedish distribution grid2015Inngår i: Proceedings of ASES Solar 2015, Pennsylvania State University, Pennsylvania, USA, July 28-30, 2015, 2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Detailed simulations of large amounts of PV production in Swedish rural power grids show that as module and system prices keep declining and thus increasing the profitability and demand for solar power, current grid performance will limit the potential. Simulations have been made on a case distribution grid (10 kV) with actual hourly load data for 2014 and calculated hourly production with respect to building roof area, tilt and azimuth together with irradiation data. At high production, especially voltage rises along cables in the outer part of the grid is problematic, but also currents in cables close to transformer buses increases substantially at these conditions. Resulting hosting capacity for the case grid is 32%, as of annual production compared to annual demand. What is limiting the hosting capacity is the tolerated voltage rise, which is set to 5% of nominal grid voltage. Through smart allocation of PV systems to the strongest nodes in the grid the hosting capacity of the same grid can be increased to 74%.

  • 305.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Development and validation of a wide-area model of hourly aggregate solar power generation2016Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 102, s. 559-566Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impact of photovoltaics (PV) on the power system becomes increasingly important to study as the penetration of PV has increased rapidly over the last decade. A physical model for aggregated PV generation has been developed for the Swedish spot market areas. Information about PV systems within the Swedish electricity certificate system and irradiance data from the meteorological model STRÅNG were used as inputs. The model was trained and validated against production data reported to the Swedish transmission system operator. Our model shows high correlation (0.95-0.99) to reported historical production data. However, it overestimates extreme 1h ramp rates, which are -20% and 22% for down- and up-ramps respectively, compared to -13% and 14% for the reported data. Furthermore a weighting function was developed, which takes demography, available solar irradiance and today's PV deployment into account, to model likely deployment in a Swedish high penetration scenario, where PV covers 6% of the total annual power demand. The difference in extreme 1 and 4 hour step changes before and after introducing PV is small. The model could thus be used with confidence to model the impact on the power system for future scenarios of high PV penetration.

  • 306.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Solenergipotentialen för Blekinges bebyggelse enligt två framtidsscenarier2014Rapport (Annet vitenskapelig)
  • 307.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Marklund, Jesper
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Boork, Magdalena
    SP Technical Research Institute of Sweden.
    Larsson, David
    School of Business Society and Engineering, Mälardalen University.
    Photovoltaics in Swedish agriculture: Technical potential, grid integration and profitability2015Inngår i: Proceedings of the ISES Solar World Congress 2015, Daegu, Korea, November 8-12, 2015, 2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper investigates the realizable potential for photovoltaic (PV) systems in Swedish agriculture. Marginal lands and available building areas for PV systems are quantified, and factors limiting the potential are analyzed. It is shown that the potential for PV in Swedish agriculture is high, but what is fully realizable is limited by the capacity of the rural power grid. A case study in the rural municipality of Herrljunga was conducted and scaled to national level. The study shows that the risk of surges in the medium voltage grid (10 kV) in rural areas are small in case where all roof surfaces with an annual solar irradiance of over 950 kWh/m2 are used for solar power. The total electricity production from the Swedish agriculture, if all roof areas with this irradiance level were used, is estimated to 4 TWh annually. With solar power on all roof surfaces with an annual irradiance of at least 900 kWh per m2 problems with voltage rise and overloads in the electricity grid might occur. The electrical grid capacities thus substantially limit how much solar power can be installed. Our results also show that the profitability limits the potential to 0.2 TWh on a national level, but that it could increase if more optimistic economic conditions are assumed.

  • 308.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Seipel, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för visuell information och interaktion. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Bildanalys och människa-datorinteraktion.
    Interactive visual simulation for photovoltaic design and planning in the built environment2013Konferansepaper (Annet vitenskapelig)
  • 309.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zimmermann, Uwe
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Characteristics of a low-cost solar irradiance loggerManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Since photovoltaic (PV) power is highly intermittent the impact on the power system has been studied more thoroughly the last few years. However, there is a lack of high resolution data needed for solar variability studies, which demand dense solar irradiance monitoring networks. Here we present a silicon cell based data logger gathering global irradiance data with sampling intervals down to one second. In all it costs around \euro 40, making it significantly cheaper than commercial products, but also cheaper compared to similar dataloggers. It has a root-mean-square error (RMSE) of 16 W/m$^2$ compared to a commercial thermopile pyranometer. Since the solar logger is intended to be used in solar variability studies,the RMSE of the clear sky index step change was studied and was shown to be 0.014 averaged over 5 minutes, and 0.029 averaged over 10 seconds. The low cost yet high accuracy of the logger, combined with its high mobility and and low power consumption makes it a viable choice when designing a monitoring network for solar variability studies or in other solar energy related projects, e.g. in developing countries, where low-cost is important.

  • 310.
    Lingfors, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zimmermann, Uwe
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Determining Intra-hour Solar Irradiance Variability with a Low-cost Solar Logger Network2014Inngår i: Proceedings of 4th International Workshop on Integration of Solar Power into Power Systems, Berlin, Germany, 10-11 November, 2014, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The study of solar irradiance is of vital importance in order to quantify the fluctuation that the transmission system needs to handle in case of large scale solar power integration. In this paper, early results from a low-cost solar irradiance logger network are presented. The main advantages of the solar logger are its low cost (~$50) and mobility. Our results confirm previous models of the station pair correlation of clear sky index step changes, with the modification that the isotropic correlation appears to decrease exponentially as a function of Δt-1/2 rather than Δt-1 as has been proposed earlier.

  • 311.
    Ljungek, Frida
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Let there be rain: An approach to an increased water access in Cameroon2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This bachelor thesis examines the pre-conditions for implementing a rain water harvesting system with additional purification on a school in a rural area of Cameroon. The villagers in this area are in general poor and lack basic access to water. The amount of rain in relation to the water need is thoroughly studied and two different UV purification are examined as potential systems for future use. The results showed that rain water harvesting is a suitable solution for the school if complemented by the further use of a natural spring nearby. The UV-systems are currently nearly non-existent on the Cameroonian market.

  • 312.
    Ljungqvist, Christina
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Lindblom, Emma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Åhgren, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    What power demand does a residential building have?: A study about electricity consumption of a residential building in Knivsta2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Knivsta municipality is planning a new climate-friendly and environmentally sustainable

    district called Nydal. The vision is to create a residential area that is minimally

    dependent on outside sources of electricity. The aim of this research is to evaluate

    the efficiency and electricity demand of a residential house in Knivsta.

    A model for the power demand of an apartment house has been constructed, using

    data for the electricity consumption of one household from Kiruna during a week in

    April. Data from the Swedish Energy Agency has been used to identify the distribution

    of electricity for the different loads. This study has focused on the electricity

    consumption of a family that consist of two adults and one child and their use of

    home appliances. A comparison between standard appliances and energy efficiency

    appliances has been made to find out how much the power and their load peaks can

    be reduced.

    The total amount of electricity consumption for the residential building’s households

    is about 93 MWh during a year. By selecting energy efficient appliances in the

    apartments the total household electricity consumption of the residential building can

    be reduced by about 55 MWh, which is almost a 60 % reduction per year. The

    residential buildings load peaks can be reduced. This can be achieved by installing

    energy efficient products by using Top Ten’s list over the most energy saving

    household appliances available on the market. Installing LED lamps and HWC driven

    products also reduces the power demand significantly. By installing HWC driven

    products in the common washhouse, the residential electricity can be reduced by 29

    %.

    A more environment-friendly lifestyle affects the electric load. The power demand can

    decrease if buying less power demanding products, but also by using the power

    demanding products in a more energy efficient way. Knivsta municipality is able to

    help the tenants in Nydal to increase their knowledge. By increasing the individuals’

    knowledge about power demand and energy saving, it is possible to influence

    individuals’ behavior and with that reduce the electric load.

  • 313. Lucchi, E.
    et al.
    Exner, D.
    D’Alonzo, V.
    Building stock analysis as a method to assess the heritage value and the energy performance of an Alpine historical urban settlement2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 482-492Konferansepaper (Fagfellevurdert)
  • 314. Luciani, A.
    et al.
    Nilsson, K.L.
    Lidelöw, S.
    Bhattacharjee, S.
    Örn, T.
    Improving the energy efficiency of built heritage in cold regions: Issues and opportunities2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 493-502Konferansepaper (Fagfellevurdert)
  • 315.
    Lund, Linnea
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Decline Curve Analysis of Shale Oil Production: The Case of Eagle Ford2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Production of oil and gas from shale is often described as a revolution to energyproduction in North America. Since the beginning of this century the shale oilproduction has increased from practically zero to currently supply almost half of theU.S. oil production. This development is made possible by the technology ofhorizontal drilling and hydraulic fracturing. Since the production has not been ongoingfor that long, production data is still fairly limited in length and there are still largeuncertainties in many parameters, for instance production decline, lifespan, drainagearea, geographical extent and future technological development. More research isneeded to be able to estimate future production and resources with more certainty.

    At the moment shale oil is extracted only in North America but around the worldinvestigations are starting to assess if the conditions are suitable from shale oilextraction elsewhere. The global technically recoverable resource has been estimatedto 345 Gb, 10% of all global technically recoverable resources. Health andenvironmental aspects of shale oil and gas production have not yet been investigatedthoroughly and there is a risk that these parameters may slow down or limit thespreading of shale development.

    This report aims to examine production patterns of shale oil wells by applying declinecurve analysis. This analysis comprises of analyzing historical production data toinvestigate how the future production may develop. The area of the study is the EagleFord shale play in Texas, U.S. The goal is to fit decline curves to production data andthen use them for making estimates of future production in the Eagle Ford.

    The production in the shale oil wells included in the study reach their peak already within a few months after production starts. After this point, production is declining.After one year, production has decreased by 75% and after two years the productionis 87% of the peak production. The hyperbolic decline curve has a good fit toproduction data and in many cases the curve is close to harmonic. It is too early todetermine whether the alternative decline curve that is tested, the scaling declinecurve, has a better fit in the long term. The report also investigates how the density of the petroleum affects the declinecurve. The result is that lighter products decline faster than heavier.

    A sensitivity analysis is performed to illustrate how different parameters affect thefuture production development. In addition to the wells’ decline rate, the assumptionson the maximum number of wells, the maximal production and the rate at which newwells are added affect the ultimately recoverable resource. These parameters all havelarge uncertainties and makes resource estimations more difficult.

  • 316.
    Lundh, Lisa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Tillförlitlighet i Stockholms elnät: En analys med hjälp av Tekla NIS2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Outages in the electric grid can be costly for society. Because of this, reliability is one of the parameters used to regulate network companies. Reliability in electrical grids can be measured with SAIDI, system average interruption duration index, which for Fortum Distribution has increased in Stockholm’s distribution network (11 kV) in the early 2000’s.

    By using outage data for Stockholm from 2011-2013, sets of parameters to be used for reliability calculations in the network information program Tekla NIS were derived. Two different options for investment were then analysed: changing old cables with high fault frequencies, and installing automatic switching in distribution substations. These options were also analysed in a simplified model built in Microsoft Excel. The model calculates the reliability of Stockholm’s distribution network using Markov chains and the network’s average line from a transmission substation’s feeder.

    The Excel model is faster than Tekla NIS but is limited and less detailed, however the results from Tekla NIS and the Excel model were found to be almost equivalent. The priority for reliability investments in Stockholm should be to change old cables of the type FCJJ since it increases the fault frequencies in the network, while an ageing network decreases the grid fees Fortum Distribution can charge.

    Simplifications and assumptions, due to insufficient outage data and some problems with Tekla NIS, had to be made when deriving parameters for reliability calculations in both Tekla NIS and the Excel model. However, Tekla NIS can be used to incorporate reliability analysis in network planning, but since Fortum Distribution currently only uses it sparsely, further testing and analysis of the programme is recommended if the usage is to increase. The Excel model can be used for making fast and rough estimates of the result of the two analysed options of investment. 

  • 317.
    Lundin, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    EROI of crystalline silicon photovoltaics: Variations under different assumptions regarding manufacturing energy inputs and energy output2013Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Installed photovoltaic nameplate power have been growing rapidly around the worldin the last few years. But how much energy is returned to society (i.e. net energy) by this technology, and which factors contribute the most to the amount of energy returned? The objective of this thesis was to examine the importance of certain inputs and outputs along the solar panel production chain and their effect on the energy return on (energy) investment (EROI) for crystalline wafer-based photovoltaics.

    A process-chain model was built using publicly available life-cycle inventory (LCI) datasets. This model has been kept simple in order to ensure transparency. Univariate sensitivity analysis for processes and multivariate case studies was then applied to the model.

    The results show that photovoltaic EROI values are very sensitive to assumptions regarding location and efficiency. The ability of solar panels to deliver net energy in northern regions of the earth is questionable. Solar cell wafer thickness have a large impact on EROI, with thinner wafers requiring less silicon material. Finding an alternative route for production of solar-grade silicon is also found to be of great importance, as is introduction of kerf loss recycling. Equal system sizes have been found to yield an primary EROI between approximately 5.5-19 depending on location and assumptions. This indicates that a generalized absolute EROI for photovoltaics may be of little use for decision-makers. Using the net energy cliff concept in relation to primary EROI found in this thesis shows that primary EROI rarely decreases to less than the threshold of 8:1 in univariate cases. Crystalline photovoltaics under similar system boundaries as those in the thesis model does not necessarily constrain economic growth on an energetic basis.

  • 318.
    Luthander, Rasmus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Improved Self-Consumption of Photovoltaic Electricity in Buildings: Storage, Curtailment and Grid Simulations2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The global market for photovoltaics (PV) has increased rapidly: during 2014, 44 times more was installed than in 2004, partly due to a price reduction of 60-70% during the same time period. Economic support schemes that were needed to make PV competitive on the electricity market have gradually decreased and self-consumption of PV electricity is becoming more interesting internationally from an economic perspective.

    This licentiate thesis investigates self-consumption of residential PV electricity and how more PV power can be allowed in and injected into a distribution grid. A model was developed for PV panels in various orientations and showed a better relative load matching with east-west-oriented compared to south-oriented PV panels. However, the yearly electricity production for the east-west-system decreased, which resulted in less self-consumed electricity. Alternatives for self-consumption of PV electricity and reduced feed-in power in a community of detached houses were investigated. The self-consumption increased more with shared batteries than with individual batteries with identical total storage capacity. A 50% reduction in feed-in power leads to losses below 10% due to PV power curtailment. Methodologies for overvoltage prevention in a distribution grid with a high share of PV power production were developed. Simulations with a case with 42% of the yearly electricity demand from PV showed promising results for preventing overvoltage using centralized battery storage and PV power curtailment.

    These results show potential for increasing the self-consumption of residential PV electricity with storage and to reduce stress on a distribution grid with storage and power curtailment. Increased self-consumption with storage is however not profitable in Sweden today, and 42% of the electricity from PV is far more than the actual contribution of 0.06% to the total electricity production in Sweden in 2014.

    Delarbeid
    1. Photovoltaic self-consumption in buildings: A review
    Åpne denne publikasjonen i ny fane eller vindu >>Photovoltaic self-consumption in buildings: A review
    2015 (engelsk)Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 142, s. 80-94Artikkel, forskningsoversikt (Fagfellevurdert) Published
    Abstract [en]

    The interest in self-consumption of PV electricity from grid-connected residential systems is increasing among PV system owners and in the scientific community. Self-consumption can be defined as the share of the total PV production directly consumed by the PV system owner. With decreased subsidies for PV electricity in several countries, increased self-consumption could raise the profit of PV systems and lower the stress on the electricity distribution grid. This review paper summarizes existing research on PV self-consumption and options to improve it. Two options for increased self-consumption are included, namely energy storage and load management, also called demand side management (DSM). Most of the papers examine PV-battery systems, sometimes combined with DSM. The results show that it is possible to increase the relative self-consumption by 13-24% points with a battery storage capacity of 0.5-1. kW. h per installed kW PV power and between 2% and 15% points with DSM, both compared to the original rate of self-consumption. The total number of papers is however rather limited and further research and more comparative studies are needed to give a comprehensive view of the technologies and their potential. Behavioral responses to PV self-consumption and the impact on the distribution grid also need to be further studied.

    Emneord
    Photovoltaics; Self-consumption; Household electricity; Energy storage; Load shifting; Demand side management
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-246975 (URN)10.1016/j.apenergy.2014.12.028 (DOI)000350935100008 ()2-s2.0-84921375090 (Scopus ID)
    Prosjekter
    Småskalig solel i byggnader - kraft för förändring i energisystem och vardagsliv
    Forskningsfinansiär
    Swedish Energy Agency
    Tilgjengelig fra: 2015-03-12 Laget: 2015-03-11 Sist oppdatert: 2018-10-10bibliografisk kontrollert
    2. PV system layout for optimized self-consumption
    Åpne denne publikasjonen i ny fane eller vindu >>PV system layout for optimized self-consumption
    2014 (engelsk)Inngår i: Proceedings of the 29th European Photovoltaic Solar Energy Conference, 2014Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    With decreasing subsidies for PV systems, increased self-consumption of PV electricity could improve the profitability of grid-connected residential PV systems. Self-consumption is in this paper defined as the share of the PV production consumed in a building on an hourly basis. With higher prices for buying than selling electricity, the revenue due to self-consumption is higher than the profit of selling electricity to the grid. The focus of this paper is the potential to increase the self-consumption with alternative PV system layouts, i.e. several different azimuth and tilt angles, called 3DPV. Hourly data from an existing PV system on a detached house outside Västerås, Sweden, combined with meteorological and spot price data of electricity has been used, all from 2011. The results of one-year simulations show increased self-consumption and decreased PV production with 3DPV compared to a south-oriented PV system. The revenue decreases with 3DPV when using historical hourly spot market data. However, there are other benefits with 3DPV such as decreased rated power of the inverter due to lower PV peak production.

    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-234181 (URN)
    Konferanse
    29th European Photovoltaic Solar Energy Conference (EU PVSEC), Amsterdam, The Netherlands, 22 - 26 September, 2014
    Tilgjengelig fra: 2014-10-14 Laget: 2014-10-14 Sist oppdatert: 2017-10-31
    3. Self-consumption enhancement and peak shaving of residential photovoltaics using storage and curtailment
    Åpne denne publikasjonen i ny fane eller vindu >>Self-consumption enhancement and peak shaving of residential photovoltaics using storage and curtailment
    2016 (engelsk)Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 112, s. 221-231Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Increasing the self-consumption of photovoltaic (PV) power is an important aspect to integrate more PV power in the power system. The profit for the PV system owner can increase and the stress on the power grid can be reduced. Previous research in the field has focused on either self-consumption of PV power in individual buildings or PV power curtailment for voltage control. In this paper self-consumption of residential PV power in a community of several single-family houses was investigated using high-resolution irradiance and power consumption data. Cases with individual or shared battery energy storages for the houses were examined. PV power curtailment was investigated as a method to reduce feed-in power to the grid, i.e. peak shaving. Results indicated that the self-consumption ratio increased when using shared instead of individual storage. Reducing the feed-in power from the community by almost 50% only led to maximum 7% yearly production losses due to curtailment and storage losses. The economics for shared storage are slightly better than for individual ones. These results suggest that residential PV-battery systems should use (i) shared energy storage options if local regulations allow it and (ii) PV power curtailment if there are incentives to lower the feed-in power.

    sted, utgiver, år, opplag, sider
    Elsevier, 2016
    Emneord
    Photovoltaics, Solar energy, Self-consumption, Energy storage, Battery, Curtailment
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-283612 (URN)10.1016/j.energy.2016.06.039 (DOI)000385318700021 ()
    Prosjekter
    Småskalig solel i byggnader – kraft för förändring i energisystem och vardaglivet
    Forskningsfinansiär
    Swedish Energy Agency, P37511-1
    Tilgjengelig fra: 2016-04-13 Laget: 2016-04-13 Sist oppdatert: 2018-10-10bibliografisk kontrollert
    4. Preventing overvoltage in a distribution grid with large penetration of photovoltaic power
    Åpne denne publikasjonen i ny fane eller vindu >>Preventing overvoltage in a distribution grid with large penetration of photovoltaic power
    2016 (engelsk)Inngår i: Proceedings of the 6th International Workshop on Integration of Solar into Power Systems / [ed] Uta Betancourt / Thomas Ackermann, Darmstadt, Germany: Energynautics GmbH, 2016, s. 113-118Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    Photovoltaic (PV) power generation is an important component in the future energy system. High penetration of PV power in a distribution power grid might however lead to overvoltage, i.e. +10% of rated voltage, for end-users. This study compares PV power curtailment and decentralized energy storage for overvoltage prevention in a 400V/10 kV distribution grid with large penetration of PV. LiDAR analysis is used to identify rooftops suitable for PV in a Swedish distribution grid with more than 5000 end-users. Results show that power curtailment allows 22% PV electricity (19 GWh) relative to total consumption on a yearly basis without overvoltage. PV production is reduced with 0.35 GWh due to curtailment. Decentralized energy storage of in total 86 MWh capacity achieves the same result.

    sted, utgiver, år, opplag, sider
    Darmstadt, Germany: Energynautics GmbH, 2016
    Emneord
    Photovoltaics, distributed generation, energy storage, distribution grid, power curtailment, Solel, distribuerad generation, energilagring, elnät
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-308821 (URN)9783981654936 (ISBN)
    Konferanse
    6th International Workshop on Integration of Solar into Power Systems, Vienna, Austria, 14-15 November 2016
    Prosjekter
    Småskalig solel i byggnader - kraft för förändring i energisystem och vardagslivetUtvärdering av tekniska lösningar för att hantera omfattande anslutning av solcellssystem i eldistributionsnät
    Forskningsfinansiär
    Swedish Energy Agency, P37511-1Swedish Energy Agency, P40864-1
    Tilgjengelig fra: 2016-11-30 Laget: 2016-11-30 Sist oppdatert: 2018-02-20
  • 319.
    Luthander, Rasmus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Stridh, Bengt
    Mälardalens högskola.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    PV system layout for optimized self-consumption2014Inngår i: Proceedings of the 29th European Photovoltaic Solar Energy Conference, 2014Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    With decreasing subsidies for PV systems, increased self-consumption of PV electricity could improve the profitability of grid-connected residential PV systems. Self-consumption is in this paper defined as the share of the PV production consumed in a building on an hourly basis. With higher prices for buying than selling electricity, the revenue due to self-consumption is higher than the profit of selling electricity to the grid. The focus of this paper is the potential to increase the self-consumption with alternative PV system layouts, i.e. several different azimuth and tilt angles, called 3DPV. Hourly data from an existing PV system on a detached house outside Västerås, Sweden, combined with meteorological and spot price data of electricity has been used, all from 2011. The results of one-year simulations show increased self-consumption and decreased PV production with 3DPV compared to a south-oriented PV system. The revenue decreases with 3DPV when using historical hourly spot market data. However, there are other benefits with 3DPV such as decreased rated power of the inverter due to lower PV peak production.

  • 320. Lysczas, M.
    et al.
    Kabele, K.
    Adaptive ventilation to improve IEQ: The case study of the pilgrimage Chapel of Holy Stairs2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 327-336Konferansepaper (Fagfellevurdert)
  • 321.
    Lännevall, Joel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Operation dependent costs of non-optimal hydropower production: Effects on the operational pattern of the Small Lule River2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In the present electrical market there is an increasing penetration of intermittent energy sources. Several studies have examined its effect on the planning of hydropower operation and the conclusion is that an increasing intermittent production is likely to result in a more variable hydropower operation, utilising a wider span of operational set points. The wear of a hydropower unit is generally at a minimum when operated close to best efficiency and increases when operating at higher or lower set points.

    This study introduces a method to calculate an operation dependent cost (ODC) function for an arbitrary hydropower unit or unit combination based on vibration measurements and operational data. The method is tested in a case study where an ODC is implemented in Akkats, located in the Small Lule River in order to evaluate its effect on operational pattern, profitability and balancing contribution.

    The results show that the implemented ODC mainly affects Akkats. For an increasing ODC, Akkats is operated closer to the best point of efficiency and the operational pattern gets less variable and the effect gets more apparent the lower the spot price. Akkats ability to follow the spot price is reduced, decreasing the earning per produced energy with a few percent­ages. Akkats balancing contribution decreases significantly more, due to a less variable operational pattern.

    The study compares the reduced ODC to the reduced spot income and concludes that the wear cost in Akkats has to be above 1,21 €/MWh in order to be economically feasible to include in the planning.

    The operational pattern for the simulated river is close to unchanged at highest price hours but during lower price hours an increasing ODC results in an increased production, due to an increasing mean flow and changed operational pattern in Akkats. More production during low prices hours results in a decreasing profitability for all plants along the river. The balancing contribution is close to unchanged in all plants except Akkats, since the production still follows the same pattern.

  • 322.
    Lätt, Ambjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Tidsupplösning vid miljövärdering av fjärrvärme: Kontorsbyggnad med solvärmeproduktion - en fallstudie2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The demand for environmental assessments on buildings and energy consumption is increasing as well as the energy performance requirements for buildings. At the same time it is increasingly common with self-producers of heat and electricity generation.

    The main purpose with this master thesis is to investigate how time resolution affects the environmental assessment of energy consumption in office buildings connected to district heating (DH). Environmental assessments were done with both attributional LCA and consequential LCA with system expansion.

    Fortum´s DH system in Stockholm was analyzed and district heating production was simulated in a Matlab-model. Greenhouse gas (GHG) emissions for the production were calculated. The heat demand of the office Gångaren 16 in Stockholm was simulated in IDA ICE. Thereafter the environmental impact in terms of GHG emissions was calculated with data from the assessment of the DH production.

    The results show that the highest time resolution that should be used for environmental assessment of energy consumption in buildings connected to DH is daily average values, regardless of LCA perspective. Moreover, sufficient results are achieved with yearly average values with attributional LCA. The results for consequential LCA with system expansion show that daily and yearly average values are not sufficient. Since peak production is temperature dependent rather than time dependent it is recommended that DH peak production is environmental assessed by temperature in future work.

  • 323. Lång, L.
    et al.
    Johansson, P.
    Capener, C-M.
    Janssen, H.
    Langmans, J.
    Møller, E.
    D’Orazio, M.
    Quagliarini, E.
    Outlining a methodology for assessing deterioration threshold criteria: Linked to retrofitting historical buildings with internal insulation2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 32-40Konferansepaper (Fagfellevurdert)
  • 324.
    Löfwall, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Energisparläge i automationsindustrin: Potential för att minska tomgångsförluster med industriella styrsystem2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Former studies have shown that a considerable part of industries’ energy usage can stem from idle times in the production. This thesis, carried out at Siemens Industry sector, evaluates the potential for using the control system to automatically put machines into energy saving mode during idle times. The main part of the thesis consists of a case study performed on machine tools at a Scania production site in Södertälje. Through load measurements the potential for energy savings was determined.

    The results show that there is a great potential for energy savings during idle times at the site. 20 to 50 percent of the machines’ energy usage can be reduced if they are put into energy saving mode when they are not used. However, the implementation of pause management in an existing control system is often too expensive to be motivated alone. Instead this should be considered before overhauls or rebuilds of machines and production sites. Another way of reducing costs can be to use a standard for pause management like PROFIenergy.

    A general conclusion is that industries with discrete manufacturing and long pause times have a great potential for energy savings. The same holds for machines with position control, such as robots and machine tools. The thesis also highlights the need for proper energy measurements at a production site in order to evaluate the potential for and results of an energy efficiency measure.

  • 325.
    Lönnberg, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Short-term regulating capacity and operational patterns of The Lule River with large wind power penetration2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The growing share of installed wind power in the Swedish electricity system has

    caused concerns whether the available regulating power will be sufficient. Several

    studies have examined the need of regulating power using both statistical and

    modelling approaches. However, there is a risk that some aspects of the short-term

    regulation of hydropower might have been missed.

    By using one of Vattenfall’s hydropower planning tools, the short-term operation of

    The Lule River has been simulated with an increasing penetration of wind power. The

    tool includes detailed models of reservoirs, generating units including efficiency curves

    and start/stop costs. By introducing a day-by-day simulation with a seven-day window

    price forecast, updated with a new wind forecast for each iteration, a 21-days

    scenario has been simulated. Transmission limits are disregarded and the thermal

    production is reduced with the average wind production.

    To quantify and compare the regulation capacity, the regulation factor is introduced.

    It reflects the ability to utilise high-price hours and considering that the need of

    regulating power for the short-term perspective is reflected in the price it will also

    reflect the regulation capacity.

    It is shown that the regulating factor is correlated to the discharge factor,whichis the

    relation between the maximum discharge to the average statistical discharge for a

    plant. A high discharge factor provides the flexibility to utilise the fluctuations in price.

    The discharge factor is adapted to the plants placement in the reach, accounting for

    both reservoirs located upstream and downstream, especially for The Lule River

    which has been designed to regulate for the fluctuations in the load. The flexibility

    required by the rest of the Nordic rivers is quantified for future studies.

    It is concluded that The Lule River is able to meet some of the fluctuations of wind

    power production due to the overcapacity ininstalled power. The production can, at

    the expense of decreased efficiency of the generating units, alter the production to

    suit a more fluctuating price.It is important to emphasise that The Lule River alone

    cannot balance a large penetration of wind power.

    To fully take into account the effects of a large penetration of wind power the study

    must be expanded to include more scenarios. The study should include different types

    of hydrological prerequisites and the seasonal variations in power production as well

    as additional rivers.

  • 326.
    Lönnberg, Joakim
    et al.
    Vattenfall R&D.
    Bladh, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Flexibility and regulation capability of hydropower systems to balance large amounts of wind power: Influence of plant properties and hydrological conditions2014Inngår i: 13th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Plants, Berlin, Germany, 11-13 Nov 2014, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The vast expansion of wind power in Sweden has raised questions about the regulation capability of existing hydropower resources. In this paper, the flexibility and relative regulation contribution of two large regulated rivers subject to increasing wind power penetration and different hydrological conditions is analysed through model-based simulations. A 28-day scenario is simulated using detailed models of the two hydropower systems, normally used at Vattenfall for day-ahead production planning. Numeric measures are introduced to measure flexibility and regulation contribution and two properties that characterise a good regulation plant are identified. It is found that the flexibility of a plant is correlated to the discharge factor and that the relative regulation contribution is nearly proportional to the available regulating power. Further it is found that large inflow of water reduces the flexibility in plants or reaches with a small discharge factor.

  • 327.
    Lövebrant, Karin
    Institutionen för energi och teknik, SLU.
    Verktyg för värdering av miljöpåverkan vid investeringar i det svenska elstamnätet2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    During the period 2009-2013, investments in the Swedish national grid increase by a factor of ten compared to previous years. In order to fulfil their mission to manage the national grid in a safe, efficient and environmentally sound way, Svenska Kraftnät (Swedish National Grid) needs to take all these perspectives into account while planning new investments. To compare and relate perspectives of technology, economy and environment the same yard stick must be used. That yard stick is commonly money. A problem arises however as environmental issues are difficult to price.

    The purpose of this master’s degree project was to develop a tool for evaluation of environmental impact related to investments in the Swedish national grid. It was initiated by and conducted at the unit for Grid development at Svenska Kraftnät. A life cycle perspective  was used and the following stages were identified: material production, construction, operation and decommissioning. The environmental impact from these stages was sorted into ten impact categories using the LCIA method ReCiPe 2008 and then two economical evaluations were performed: one at midpoint level and one at endpoint level. Also included in the evaluation were the change in power losses or in the power production mix and the visual impact coming from overhead transmission lines.

    The tool was implemented in Excel and offers the possibility to evaluate the environmental impact from five different power line technologies (per km), substation line bays (per bay), transformers (per piece) and reactors (per piece). The main results show that AC land cable has a significantly higher environmental impact and cost than the other power line technologies. Material production and construction are the life cycle stages that contribute the most to the environmental cost. The impact categories that affect the environmental cost the most are climate change (for midpoint evaluation) and resource depletion (for endpoint evaluation). When the investment affects the power production mix, e.g. by changing the transmission capacity to another country, the subsequent environmental impact can be very influential on the total environmental cost of the investment.

  • 328. Mallia, M.R.
    et al.
    Prizeman, O.
    Energy Performance Certification: Is the software currently used in Malta suitable for the energy assessment of its historic buildings?2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 264-273Konferansepaper (Fagfellevurdert)
  • 329.
    Mancebo, Carlos Díaz-Asensio
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    COMPARISON STUDY FOR WIND RESOURCE ASSESMENT IN COMPLEX DOMAIN USING METEODYN AND WINDSIM2014Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Two commercial Computational Fluid Dynamic (CFD) wind resource assessment tools namely Meteodyn WT and Windsim have been compared for an embankment site named Hjardemål. For comparison of both software, a controlled experiment is carried out for a fixed set-up with same domain size and same number of cells in the X, Y and Z directions. Wind flow has been assessed in the perpendicular upstream direction to the embankment. Vertical wind profiles observed on site at four different towers distributed (-397.69 m) before, (0 m) at, (30.83 m) just after and (199.16 m) after the embankment are compared with both software outputs. Results show that Meteodyn WT predicts closer vertical wind profiles before, at and after whilst wind Windsim predicts a closer wind profile just after the embankment. The discussion of results is based on the limitations of both software tools which have conditioned the comparison.

  • 330.
    Manzetti, Sergio
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Beräkningsbiologi och bioinformatik. Fjordforsk AS Inst Sci & Technol, Energy Sci, N-6894 Midtun, Vangsnes, Norway..
    Mariasiu, Florin
    Tech Univ Cluj Napoca, Automot Engn & Transports Dept, Cluj Napoca 103105, Clausenburg, Romania..
    Electric vehicle battery technologies: From present state to future systems2015Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 51, s. 1004-1012Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Electric and hybrid vehicles are associated with green technologies and a reduction in greenhouse emissions due to their low emissions of greenhouse gases and fuel-economic benefits over gasoline and diesel vehicles. Recent analyses show nevertheless that electric vehicles contribute to the increase in greenhouse emissions through their excessive need for power sources, particularly in countries with limited availability of renewable energy sources, and result in a net contribution and increase in greenhouse emissions across the European continent. The chemical and electronic components of car batteries and their waste management require also a major investment and development of recycling technologies, to limit the dispersion of electric waste materials in the environment. With an increase in fabrication and consumption of battery technologies and multiplied production of electric vehicles worldwide in recent years, a full review of the cradle-to-grave characteristics of the battery units in electric vehicles and hybrid cars is important. The inherent materials and chemicals for production and the resulting effect on waste-management policies across the European Union are therefore reported here for the scope of updating legislations in context with the rapidly growing sales of electric and hybrid vehicles across the continent. This study provides a cradle-to-grave analysis of the emerging technologies in the transport sector, with an assessment of green chemistries as novel green energy sources for the electric vehicle and microelectronics portable energy landscape. Additionally, this work envisions and surveys the future development of biological systems for energy production, in the view of biobatteries. This work is of critical importance to legislative groups in the European Union for evaluating the life-cycle impact of electric and hybrid vehicle batteries on the environment and for establishing new legislations in context with waste handling of electric and hybrid vehicles and sustain new innovations in the field of sustainable portable energy.

  • 331. Marincioni, V.
    et al.
    Altamirano-Medina, H.
    Can probabilistic risk assessment support decision-making for the internal insulation of traditional solid brick walls?2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 50-59Konferansepaper (Fagfellevurdert)
  • 332.
    Marklund, Jesper
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Potential för storskalig anslutning av solel i landsbygdsnät2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The study examines the potential for extensive connection of photovoltaic (PV) production in the Swedish rural power grid, considering the case distribution grid (10kV) of Herrljunga Elektriska. Hourly PV production is calculated using radiation and temperature data together with information regarding building roofs in the studied area. Furthermore, hourly customer load data is aggregated, enabling detailed power flow simulations of the grid resulting in hourly voltages and currents for all nodes during 2014. Three cases with varying PV production are studied, using different thresholds for minimum annual radiation. Thus, roofs with lower annual radiation are excluded from the simulations, limiting PV production. The three cases considers annual radiation greater than 0 kWh/m2 , 700 kWh/m2 and 1000 kWh/m2.

    Simulations show that the distribution grid in Herrljunga maintains acceptable performance with respect to voltages and currents for the 1000 kWh/m2,year case, yielding an annual production of 30 % of consumption. The hosting capacity, which is an estimate of the amount of PV that can be connected to the grid, is therefore 30 %. In order to further examine grid limitations, weak parts of the grid are identified. These are situated in the peripheral parts of the grid, which is in accordance with earlier studies of intermittent power production in distribution grids. Additionally, low voltage grids in connection to these weaker parts of the distribution grid are simulated, showing no further limitations for hosting capacity.

  • 333.
    Marstorp, Jonathan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Trolle, Sten
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optimering av solcellssystem och implementering av ett Energy Management System: Möjligheter för ett framtida bostadsområde2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Riksbyggen, one of Sweden’s largest real estate companies, are planning to build a new residential area outside Uppsala, Sweden. Adjacent to the houses in the area, Riksbyggen are considering installing a 137 kWp photovoltaic (PV) system to supply the residents with renewable energy.

    In the first part of this study, the proposed PV system is analyzed based on benefits and profitability for the residents, using the software HOMER. Possibilities for including 3 kWp roof-mounted PV systems with varying azimuth as a complement to the larger system are evaluated.

    In the second part, options for implementing an Energy Management System (EMS) with battery storage or load shifting in the distribution grid using MATLAB. The system uses forecasting of PV generation, electricity prices and electricity demand to optimize the system control strategies.

    The results from the study indicate that installation of the 137 kWp PV system could lead to reduced average electricity costs of 21,1 % for the residents. If the system is completed with roof-mounted PV modules of varying azimuth for 12 % of the households in the area, the average electricity cost is reduced by 29,4 %in total.

    Implementing an EMS with energy storage in the distribution grid was not found to be an economically viable option, mainly due to high energy storage costs. The system control strategies can be improved by using forecasting. The economic benefits of load shifting for a single household were found to be too low to give incentive for system investment.

  • 334. Marszal-Pomianowska, Anna
    et al.
    Stoustrup, Jakob
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Le Dréau, Jérôme
    Simple flexibility factor to facilitate the design of energy-flex-buildings2017Inngår i: Proceedings of Building Simulation 2017, San Francisco, California, USA, August 7-9, 2017, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Buildings can facilitate a safe and uninterrupted transition from traditional production-respond to future demand-respond energy systems by delivering flexibility service to the system with smart control of their energy loads. Current methods used for building design and performance evaluation are focused on minimizing the building energy use and do not quantify the flexibility potential of the buildings. As the energy flexibility is of interest for the built and network environment, this paper presents a simple energy flexibility factor, which combines the needs of both and can be easily applied during the simulation/design and operation phases of a building.

  • 335.
    Martens, Sonja
    et al.
    GFZ German Res Ctr Geosci, Potsdam.
    Hangx, Suzanne
    Univ Utrecht, Earth Sci, Utrecht.
    Juhlin, Christopher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Geofysik.
    Kuehn, Michael
    GFZ German Res Ctr Geosci, Potsdam.
    Kempka, Thomas
    GFZ German Res Ctr Geosci, Potsdam.
    Energy, Resources and the Environment: Meeting the challenges of the future2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 125, s. 1-5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The European Geosciences Union (EGU) brings together geoscientists from all over the world covering all disciplines of the Earth, planetary and space sciences. This geoscientific interdisciplinarity is needed to tackle the challenges of the future. One major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources in efficient and environmentally sustainable ways. This Energy Procedia issue provides an overview of the contributions of the Division on Energy, Resources & the Environment (ERE) at the EGU General Assembly 2017.

  • 336.
    McCarthy, John
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    WIND FARM DECOMMISSIONING: A DETAILED APPROACH TO ESTIMATE FUTURE COSTS IN SWEDEN2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Although targets for renewable energy exist in Sweden, developing wind energy has proven to be challenging for developers. This is due in part to the demands made by authorities for monetary amounts to be set aside to take care of wind turbine dismantling and site restoration costs at the end of their lifecycle. There has been a large degree of uncertainty surrounding the amounts being demanded and the level to which sites must be restored, partially due to a lack of guidelines. Coupled with ambiguity, there has been a tendency by authorities and developers to use figures from previous high court decisions and previous permit applications to project decommissioning costs for current applications.This thesis evaluates seven different wind farm decommissioning scenarios using a model developed to estimate future costs, with the turbine model and the quantity of turbines being the parameters that vary. The model uses data from numerous sources, including real case decommissioning projects and figures from an existing model that had already been used to forecast costs in Sweden. One of the assumptions of the model developed is that scrap metals in wind turbines will have a residual value when decommissioning occurs; this was not allowed for in a recent decision made by a county administrative board following an environmental high court decision. An argument is made to justify that a minimum scrap value for wind turbines should be considered, based on the findings of the model. A further case is made to allow for the security bonds to be paid over an extended period of time, considering the initial value of wind farms.The results of the model show that the turbine model has an impact on the decommissioning costs and the potential residual value that can be obtained. In addition, the quantity of the wind turbines has a considerable effect on the decommissioning costs. These results suggest that each wind development project should be treated on a case-by-case basis using a calculation-based approach when determining the cost for a security bond. Recommendations for future research include considering wind farm location in the model.

  • 337. Mickelsson, Anton
    Energikartläggning och beräkningsstrategier för energiflöden i byggnader: En fallstudie av Vallongatan 12016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Energy audit and calculation strategies for energy flows in buildings: a case study of Vallongatan 1

     

    This thesis involves an energy audit of a building with offices and laboratories in Uppsala, Sweden. The calculations are performed in Microsoft Excel and were later used as the basis for developing calculation strategies for similar, future, energy audits.

     

    The building was erected in the early 1990s and the heating requirement of just above 700 MWh is covered by district heating from the city network. The total gross floor area is about 8400 m2 and is served by an air conditioning system consisting of seven ventilation units with rotary heat exchangers, heating and cooling coils, as well as water radiators throughout the building.

     

    No significant improvement measures have been implemented since the construction, and the building therefore has a potential to improve its energy performance. The report addresses a number of measures that could be taken, as well as an evaluation of each one. The most economically viable of these would be to clean the rotary heat exchangers, which is deemed to have a potential to save about 70 MWh or 48 700 SEK annually. In comparison to the estimated cost of between 35 000 and 42 000 SEK this is likely to become profitable as early as the first year.

     

    The calculation templates that were developed cover three different building standards, these are categorized as low, improved and advanced standard. Here, the desired areas and types of activities are typed in easily for either individual rooms or entire offices or buildings. The templates provide estimates regarding power and energy needs for heating and comfort cooling, recommended air flows, heat development and dissipation as well as carbon dioxide concentration in the room air.

  • 338.
    Mohammadi, Ali
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Sustainable building portfolioinvestment practices: Evaluation of the GRESB international weightingframework2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    GRESB is an industry-driven organization, which helps real estateinvestors assess the sustainability performance of real estate portfoliosaround the world. This important assessment is done based on thedeveloped GRESB framework and through a yearly survey, which consists of59 questions. The GRESB survey is categorized in seven groups and covers42 different criteria.In this research paper, the GRESB framework is analyzed qualitatively andquantitatively. The qualitative analysis includes investigating whichsustainability aspects are covered by each question from both GRESB pointof view and Conventional point of view. The whole framework is mapped onthe basis of defined sustainability categories. As the second step ofqualitative analysis, a deeper investigation is done in order to observethe intentions behind every question of the GRESB survey. As anaccomplishment to this step, the outcomes of the questions are outlined.On the other hand, considering the current equally-weighted criteria andto address the need for a more adaptive sustainability framework, aquantitative analysis of some selected parameters which are highlydependent on the location of a building was performed and a locationbased approach is proposed. In this regard, three building types(residential, office and school) were selected to accomplish thesimulations in three different locations (Iran, Australia and SierraLeone) in order to compare them and observe the differences.Evidently, the proposed approach based on the specific location, couldlead to more outcome-oriented, fair, and more accurate portfolioassessments that takes into account each building’s local opportunitiesand limitations.

  • 339.
    Mohr, Steve
    et al.
    The University of Newcastle, School of Engineering.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Mudd, Gavin
    University of New South Wales, Institute of Environmental Studies.
    Evans, Geoffrey
    The University of Newcastle, School of Engineering.
    Projection of long-term paths for Australian coal production: comparisons of four models2011Inngår i: International Journal of Coal Geology, ISSN 0166-5162, E-ISSN 1872-7840, Vol. 86, nr 4, s. 329-341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Coal exports are an important source of revenue for Australia and for this reason Australian coal production and resources have been examined in detail and two recoverable resource estimates determined namely Standard and High. The Standard case calculated the likely recoverable coal resources in Australia to be 317 Gt, whereas the High scenario determined the maximal amount of recoverable coal resources at 367 Gt. Different modelling approaches (Logistic, Gompertz, Static and Dynamic supply and demand models) were used to project fossil fuel production and the projections of the relative approaches were compared. Good agreement was found between the Logistic, Static and Dynamic supply and demand models with production peaking in 2119 +/- 6 at between 1.9 and 3.3 Gt/y. Contrasting these projections the Gompertz curves peak in 2084 +/- 5 at 1-1.1 Gt/y. It was argued that the Logistic, Static and Dynamic models are more likely to produce accurate projections than the Gompertz curve. The production forecast is based on existing technology and constraints and a qualitative discussion is presented on possible influences on future production, namely: export capacity, climate change, overburden management, environmental and social impacts and export market issues.

  • 340.
    Molin, Andreas
    et al.
    Linköpings universitet.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Moshfegh, Bahram
    Linköpings universitet.
    Increasing photovoltaic power supply self-consumption by on-site batteries for a large flat-roof industrial premise2013Inngår i: Proceedings of the 28th European Photovoltaic Solar Energy Conference (EU PVSEC), Paris, France, September 30 - October 4, 2013., 2013Konferansepaper (Fagfellevurdert)
  • 341. Molin, Andreas
    et al.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Stridh, Bengt
    Karlsson, Björn
    Konsekvenser av avräkningsperiodens längd vid nettodebitering av solel2010Rapport (Fagfellevurdert)
  • 342.
    Molinari, Marco
    et al.
    KTH, Stockholm, Sweden.
    Broström, Tor
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Exergy analysis of different solutions for humidity control in heritage buildings2011Inngår i: World Renewable Energy Congress – Sweden, 8–13 May, 2011, Linköping, Sweden: Volume 8 (Low-Energy Architecture), Linköping: Linköping University Electronic Press, Linköpings universitet , 2011, s. 2041-2048Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Energy use in the building stock represents a major contribution to the total energy use in developed countries. Increasing limitations to the energy demand of the new buildings have been imposed by the building codes in the last decades, which resulted in improved building envelopes.

    Yet, in many cases it is not either technically or economically feasible to improve the existing building shells. A typical example is represented by historical buildings, such churches and old buildings, which often may not be improved for aesthetical or economic reasons. Often poorly insulated, such buildings would require a high energy demand to keep them at the preferable hygro-thermal conditions. As a consequence they are often left unheated, which also affects the usability of these buildings. However, the risk of moisture damage often requires them to be slightly heated to a certain temperature.

    As the energy demand is linked to the possibility of improving the building shell, for instance by adding insulation or making it more airtight, the exergy approach gives interesting insights on the problem. Exergy analysis emphasizes the thermodynamic valuable part of the energy demand in the building and straightforwardly defines the minimum energy demand for a certain process. The energy demand being equal, it is still possible to lower the exergy demand and consumption. A lower exergy demand paves the way to the exploitation of renewable sources, such as solar power.

    Often the main task is to keep the RH humidity within a certain range. Aim of this paper is to perform a theoretical exergy analysis of three different solutions for lowering the RH in the building. The basic approach keeps the temperature of the indoor space at a constant level. A second approach-the so-called conservation heating- consists in letting the temperature vary according to the maximum allowed indoor relative humidity. In the third case the target is reached by means of a dehumidification process. Advantages and disadvantages of the different approaches are shown under the energy and exergy points of view.

    The present research is done within the framework of the “Spara och bevara” project, which targets cost-efficient solutions for the conservation and the use of heritage buildings in Sweden and the IEA Annex49 and ESF COSTexergy projects, which aim at energy-efficient buildings and communities through the application of the low-exergy approach.

  • 343.
    Monie, Svante
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Energilagring för distribuerad produktion av solcellsel: Energilagringstekniker som kan öka nätets acceptansnivå för distribuerad produktion2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a future situation with a large implementation of photo voltaic (PV) in the local distribution grid one expects voltage and current related problems to occur due to the large portion of excess electricity from the PV fed into the grid. In this study it was concluded, based on experiences from Germany and Italy, that energy storages are assumed to be beneficial in order to address these problems. The location of storages needs to be distributed among the low voltage grid (400 V) to be able to reduce excess produced electricity from PV as well as deliver peak reducing power (“peak shaving”). This suggests that large scale techniques are not suitable for this purpose since they will be dependent on transmission bottle necks. The energy storages would be most efficient if set up as a combination of a local storage, at the end consumer, and an aggregated storage distributed within the low voltage grid. Techniques suggested are advanced gel-based lead silicon batteries for rapid power response and fuel cell systems with separate electrolysis unit for bulk storage. Thus the systems can divide the needed amount of energy to store in a more efficient way. This suggests that a business model could be a leasing or rental based system where the end consumer subscribes for the technique and services. The major benefits from the energy storage was found to be reduced power flows in the grid (both load- and production wise) as well as reduced volatility in the system. Furthermore, the energy storage would be able to serve as back-up or black start source (also referred to as “cold start” in case of power outages), as well as offering filtering services for reduction of noise and harmonics. Since the major benefits are of systemic nature the most likely actor to gain from energy storages would be distribution system operators (DSO). Therefore the Swedish regulations needs to be adjusted so DSO’s are allowed to, firstly, include the costs for energy storages and, secondly, deliver energy from energy storages without being considered as producers.

  • 344.
    Monie, Svante
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nilsson, Annica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Åberg, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Thermal Energy Storages in Residential Areas: – a potential to increase renewable power generation?2018Inngår i: 2018 ACEEE Summer Study on Energy Efficiency in Buildings: Making Efficiency Easy and Enticing / [ed] Fred Grossberg, Washington D.C., 2018, Vol. 20, s. 11-1-11-12, artikkel-id 0194_0286_000156Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With an increased ambition of implementing renewable electricity production in our energy systems follows the need of handling the inherent variability from some of these production sources (e.g. wind and solar). This could be via curtailments, infrastructural reinforcements of the power grid, and/or increased utilization of power system reserves. The aim of this study was to investigate if power surplus and deficit due to mismatch between intermittent power generation and power demand could be reduced with electric heat pumps (used for power-to-heat purposes), combined heat and power (CHP) production (for power balancing), and seasonal thermal energy storage (STES) (as buffering capacity). A residential area consisting of buildings refurbished for improved energy performance, roof top solar photovoltaic (PV) systems, a local heat distribution system, a small-scale CHP plant, central heat pumps, and a STES, was simulated. The heat pumps were given priority to use surplus power from roof top PV generation or surplus from the grid (e.g. wind power). The CHP plant produced power during power deficits. Surplus heat from the CHP plant as well as from the heat pumps was stored in the STES. The results showed a reduction of the surplus power from the local PV systems towards the upstream power grid. Also, the possibility to offer regulative service towards upstream power grid by using CHP was demonstrated. The conclusion is that power-to-heat and CHP can significantly reduce the mismatch between variable power generation and power demand.

  • 345.
    Montenegro Borbolla, Ivan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Using refurbished turbines to provide affordable wind energy: A case study in Africa2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    When a wind farm is repowered, decommissioned turbines are discarded. This creates a stock of wind turbines that can be acquired for a fraction of the original cost, and refurbished. Taking advantage of the reduced price and the ruggedness of first generation wind turbines, new markets for sale of wind energy can be explored.

    This thesis first analyses the repowering background of Germany, Denmark, and other European countries, where transition to repowered or “second generation” wind farms is taking place.

    Then, a number of feasibility studies are reviewed to create a study framework, which will allow in-depth study of suitable energy markets. Using this framework, the suitability of four countries is analysed in detail: Djibouti, Madagascar, Mozambique, and Tanzania.

    Two countries are selected to perform a total of 6 site studies: Djibouti and Tanzania. Using WindPro 2.9, six model wind farms are simulated. A financial model is built, based on an NREL study, to analyse the economic viability of wind farms.

    Using the financial model, the levelized cost of energy is obtained, and used to evaluate the competitiveness of the model wind farms. A sensitivity study is carried out to identify the major influences on the LCOE. Using the cost data, the cost competitiveness of the proposed wind farms is discussed, including competitiveness in the target markets, and a cost comparison with commercial wind farms with new turbines is performed. Five out of six proposed wind farms are competitive in price in the target markets, and all achieve an average installation cost per kW of one third of conventional wind farms, while producing energy in the low range of commercial projects, and even lower for sites with excellent wind resources. 

  • 346. Moshfegh, B.
    et al.
    Rohdin, P.
    Milic, V.
    Donarelli, Anna
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    Eriksson, Petra
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    Broström, Tor
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    A method to assess the potential for and consequences of energy retrofits in Swedish historic districts2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 302-310Konferansepaper (Fagfellevurdert)
  • 347.
    Mosiej, Józef
    et al.
    Warsaw University of Life Sciences.
    Karczmarczyk, Agnieszka
    Warsaw University of Life Sciences.
    Wyporska, Katarzyna
    Warsaw University of Life Sciences.
    Rodzkin, Aleh
    International Sakharov Environmental University, Minsk, Belarus.
    17. Biomass Production in Energy Forests: Short Rotation Plantations2012Inngår i: Rural Development and Land Use / [ed] Lars Rydén and Ingrid Karlsson, Uppsala: Baltic University Press , 2012, 1, s. 196-202Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 348. Mourão, J.
    et al.
    Campos, V.
    Balancing cultural and environmental values in buildings refurbishment: Assessing integrity and energy2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 539-548Konferansepaper (Fagfellevurdert)
  • 349.
    Mummery, Robert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    What are the uncertainties and potential impacts of "Brexit"/the EU referendum result on the UK wind energy sector?2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study examines the potential effects of Brexit on the wind power industry within the UK. It became apparent that in order to reach the objective that the approach of the research needed to be broadened as it was found that Brexit has potential effects in many areas of the UK's electricity industry, including the import and export of electricity and the associated fuels used in the generation of electricity.

    It was found that in the event of a hard Brexit, one with no deal, that the UK's physical connections by undersea cables with the EU may be disrupted. There is a raft of legislation within the Internal Energy Market (IEM) governing this issue that will need a complete rewrite should the UK be forced to leave the IEM.

    Consideration was given to the effect of Brexit on the three main traditional methods used to generate electricity in the UK, coal, gas and nuclear power and how wind powered energy could be used to fill any shortfall directly or indirectly caused by Brexit. The UK Government has pledged to eradicate the use of coal in generating electricity by 2025 so the study considered only the short term effect of this. For gas, the UK is a net importer, albeit mainly from outside the EU, so the implications of Brexit on gas fired generation of electricity were discussed and found to be negligible. For nuclear powered electricity generation the implications were found to be more serious. The UK would have to resign its membership of Euratom, the European Atomic Agency Community. The potential implications of this include, limited access to nuclear fuel, and reduced participation into nuclear research carried out by the EU. The scope of Euratom also includes a large variety of areas including the safeguarding of nuclear materials in storage and in transit along with radiation protection. Plans by two Japanese companies to build new nuclear power stations in the UK have been shelved with Brexit adding to the uncertainty of their viability. It was found that the combined implications of the above could result in a shortfall in the medium term provision of electricity within the UK. Finally it was discussed whether or not wind powered energy could fill this void and it was found that the UK Government could overcome the deficiency by encouraging investment in wind power by increasing the value of their Contract for Difference, CfD,  auctions.

  • 350.
    Munkhammar, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Distributed Photovoltaics, Household Electricity Use and Electric Vehicle Charging: Mathematical Modeling and Case Studies2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Technological improvements along with falling prices on photovoltaic (PV) panels and electric vehicles (EVs) suggest that they might become more common in the future. The introduction of distributed PV power production and EV charging has a considerable impact on the power system, in particular at the end-user in the electricity grid.

    In this PhD thesis PV power production, household electricity use and EV charging are investigated on different system levels. The methodologies used in this thesis are interdisciplinary but the main contributions are mathematical modeling, simulations and data analysis of these three components and their interactions. Models for estimating PV power production, household electricity use, EV charging and their combination are developed using data and stochastic modeling with Markov chains and probability distributions. Additionally, data on PV power production and EV charging from eight solar charging stations is analyzed.

    Results show that the clear-sky index for PV power production applications can be modeled via a bimodal Normal probability distribution, that household electricity use can be modeled via either Weibull or Log-normal probability distributions and that EV charging can be modeled by Bernoulli probability distributions. Complete models of PV power production, household electricity use and EV home-charging are developed with both Markov chain and probability distribution modeling. It is also shown that EV home-charging can be modeled as an extension to the Widén Markov chain model for generating synthetic household electricity use patterns. Analysis of measurements from solar charging stations show a wide variety of EV charging patterns. Additionally an alternative approach to modeling the clear-sky index is introduced and shown to give a generalized Ångström equation relating solar irradiation to the duration of bright sunshine.

    Analysis of the total power consumption/production patterns of PV power production, household electricity use and EV home-charging at the end-user in the grid highlights the dependency between the components, which quantifies the mismatch issue of distributed intermittent power production and consumption. At an aggregate level of households the level of mismatch is shown to be lower.

    Delarbeid
    1. Simulating dispersed photovoltaic power generation using a bimodal mixture model of the clear-sky index
    Åpne denne publikasjonen i ny fane eller vindu >>Simulating dispersed photovoltaic power generation using a bimodal mixture model of the clear-sky index
    2015 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Improved probability distribution models for power generation are useful e.g. forprobabilistic power flow simulations. This paper presents a distribution modelfor photovoltaic (PV) power generation based on the clear-sky index.With the use of minute-resolution data on globalhorizontal irradiation (GHI) we fit unimodal normal,bimodal normal and trimodal normal mixture distributionfamilies to the clear-sky index. Based on Kolmogorov-Smirnov (K-S) teststhe best fit distribution family consisting of a bimodal normal distribution isthen used for estimating an aggregate clear-sky index for multipledispersed locations that are assumed to be uncorrelated in terms of sky clearness.For five or more locations the aggregate clear-sky indexfollows a normal distribution due to the central limit theorem.Models for solar radiation on tilted planes and PV power generation areapplied to the clear-sky index to generate probability distributions for anarbitrary PV system.

    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-242439 (URN)
    Konferanse
    EU PVSEC - 31st European Photovoltaic Solar Energy Conference and Exhibition, 14-18 September, 2016, Hamburg, Germany
    Tilgjengelig fra: 2015-01-26 Laget: 2015-01-26 Sist oppdatert: 2018-02-20bibliografisk kontrollert
    2. On a Probability Distribution Convolution Approach to Clear-Sky Index and a Generalized Ångström Equation
    Åpne denne publikasjonen i ny fane eller vindu >>On a Probability Distribution Convolution Approach to Clear-Sky Index and a Generalized Ångström Equation
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    We show that by modeling solar beam irradiance approximately as a simple Bernoulli distribution and diffuse irradiance as a Gamma distribution, a generalized Ångström equation relating solar irradiation to sunshine hours follows directly as aconsequence of the convolution of beam and diffuseirradiance distributions into a distribution for the clear-sky index.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-242441 (URN)
    Tilgjengelig fra: 2015-01-26 Laget: 2015-01-26 Sist oppdatert: 2017-10-27bibliografisk kontrollert
    3. Characterizing probability density distributions for household electricity load profiles from high-resolution electricity use data
    Åpne denne publikasjonen i ny fane eller vindu >>Characterizing probability density distributions for household electricity load profiles from high-resolution electricity use data
    2014 (engelsk)Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 135, s. 382-390Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents a high-resolution bottom-up model of electricity use in an average household based on fit to probability distributions of a comprehensive high-resolution household electricity use data set for detached houses in Sweden. The distributions used in this paper are the Weibull distribution and the Log-Normal distribution. These fitted distributions are analyzed in terms of relative variation estimates of electricity use and standard deviation. It is concluded that the distributions have a reasonable overall goodness of fit both in terms of electricity use and standard deviation. A Kolmogorov-Smirnov test of goodness of fit is also provided. In addition to this, the model is extended to multiple households via convolution of individual electricity use profiles. With the use of the central limit theorem this is analytically extended to the general case of a large number of households. Finally a brief comparison with other models of probability distributions is made along with a discussion regarding the model and its applicability.

    Emneord
    Household electricity use, Stochastic modeling, Probability density distributions, Weibull distribution
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-240062 (URN)10.1016/j.apenergy.2014.08.093 (DOI)000345470100036 ()
    Tilgjengelig fra: 2015-01-05 Laget: 2015-01-05 Sist oppdatert: 2017-12-05bibliografisk kontrollert
    4. PHEV Home-Charging Model Based on Residential Activity Patterns
    Åpne denne publikasjonen i ny fane eller vindu >>PHEV Home-Charging Model Based on Residential Activity Patterns
    Vise andre…
    2013 (engelsk)Inngår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 28, nr 3, s. 2507-2515Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Plug-in hybrid electric vehicles (PHEVs) have received an increased interest lately since they provide an opportunity to reduce greenhouse gas emissions. Based on the PHEV introduction level in the car park, the charging behaviors in an area will induce changes in the load profiles of the power system. Hence, it becomes important to investigate what impact a given PHEV introduction level has on load profiles due to expected charging behavior of residents. This paper proposes a new model for generating PHEV home-charging patterns by combining PHEV usage with synthetic activity generation of residents' electricity-dependent activities. The synthetic activity data are simulated based on time-use data collected in time diaries, and define the basis for calculations of the PHEV home-charging behavior as well as the resident's electricity consumption. The proposed model is generic and can be used where similar residential time-use data are available. Based on the underlying activities, the model estimates the total load profile due to residential load as well as the variation in the load profile. The resulting load profiles can be used in load shaving studies in order to investigate what type of activities, PHEV usage or other, may be moved to hours with lower demand.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-195823 (URN)10.1109/TPWRS.2012.2230193 (DOI)000322989900046 ()
    Tilgjengelig fra: 2013-02-27 Laget: 2013-02-27 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    5. A Bernoulli Distribution Model for Plug-in Electric Vehicle Charging based on Time-use Data for Driving Patterns
    Åpne denne publikasjonen i ny fane eller vindu >>A Bernoulli Distribution Model for Plug-in Electric Vehicle Charging based on Time-use Data for Driving Patterns
    2014 (engelsk)Inngår i: Proceedings of IEEE International Electric Vehicle Conference (IEVC), 2014Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper presents a Bernoulli distribution model for plug-in electric vehicle (PEV)charging based on high resolution activity data for Swedish drivingpatterns. Based on the activity ``driving vehicle" from a time diary studya Monte Carlo simulation is made of PEV state of chargewhich is then condensed down to Bernoulli distributions representingcharging for each hour during weekday and weekend day. Thesedistributions are then used as a basis for simulations of PEVcharging patterns. Results regarding charging patterns for a numberof different PEV parameters are shown along with a comparison with resultsfrom a different stochastic model for PEV charging. A convergence test forMonte Carlo simulations of the distributions is also provided.In addition to this we show that multiple PEV charging patterns are representedby Binomial distributions via convolution ofBernoulli distributions. Also the distribution for aggregatecharging of many PEVs is shown to be normally distributed. Finally a fewremarks regarding the applicability of the model are given along witha discussion on potential extensions.

    HSV kategori
    Forskningsprogram
    Engelska
    Identifikatorer
    urn:nbn:se:uu:diva-242437 (URN)10.1109/IEVC.2014.7056224 (DOI)
    Konferanse
    IEEE International Electric Vehicle Conference (IEVC), 17-19 Dec. 2014, Florence, Italy
    Tilgjengelig fra: 2015-01-26 Laget: 2015-01-26 Sist oppdatert: 2016-05-27bibliografisk kontrollert
    6. Household electricity use, electric vehicle home-charging and distributed photovoltaic power production in the city of Westminster
    Åpne denne publikasjonen i ny fane eller vindu >>Household electricity use, electric vehicle home-charging and distributed photovoltaic power production in the city of Westminster
    Vise andre…
    2015 (engelsk)Inngår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 86, s. 439-448Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this paper we investigate household electricity use, electric vehicle (EV) home-charging and distributed photovoltaic (PV) power production in a case study for the city of Westminster, London. Since it is economically beneficial to maximize PV power self-consumption in the UK context the power consumption/production patterns with/without introducing EV home-charging on the household level is investigated. Additionally, since this might have an effect on the electricity use on an aggregate of households a large-scale introduction of EV charging and PV power production in the entire city of Westminster is also investigated. Household electricity consumption and EV home-charging are modeled with a Markov-chain model. PV power production is estimated from solar irradiation data from Meteonorm for the location of Westminster combined with a model for photovoltaic power production on tilted planes. The available rooftop area is estimated from the UK map geographic information database. EV home-charging increases the household electricity use mainly during evening with a maximum during winter whereas PV produces power during daytime with maximum during summer. On the household level this mismatch introduces variability in power consumption/production, which is shown to be less prominent for the large-scale scenario of the entire city of Westminster.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-236895 (URN)10.1016/j.enbuild.2014.10.006 (DOI)000347494900041 ()
    Tilgjengelig fra: 2014-11-25 Laget: 2014-11-25 Sist oppdatert: 2017-12-05bibliografisk kontrollert
    7. Quantifying self-consumption of on-site photovoltaic power generation in households with electric vehicle home charging
    Åpne denne publikasjonen i ny fane eller vindu >>Quantifying self-consumption of on-site photovoltaic power generation in households with electric vehicle home charging
    2013 (engelsk)Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 97, s. 208-216Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Photovoltaic (PV) power production and residential power demand are negativelycorrelated at high latitudes on both annual and diurnal basis. If PVpenetration levels increase, methods to deal with power overproduction in the localdistribution grids are needed to avoid costly grid reinforcements. Increased local consumption isone such option. The introduction of a home-chargedplug-in electric vehicle (PEV) has a significant impact on the household load and potentiallychanges the coincidence between household load and photovoltaic power production.This paper uses a stochastic model to investigate the effect on the coincidence between householdload and photovoltaic power production when including a PEV load. The investigationis based on two system levels: (I) individual householdlevel and (II) aggregate household level. The stochastic model produces theoretical high-resolutionload profiles for household load and home charged PEV load over time.The photovoltaic power production model is based on high-resolution irradiance data for Uppsala, Sweden.It is shown that the introduction of a PEV improves the self-consumption of the photovoltaicpower both on an individual and an aggregate level, but the increase is limited due to thelow coincidence between the photovoltaic power production pattern and the charging patterns of the PEV.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-195831 (URN)10.1016/j.solener.2013.08.015 (DOI)000326851400023 ()
    Tilgjengelig fra: 2013-02-27 Laget: 2013-02-27 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    8. On a probability distribution model combining household power consumption, electric vehicle home-charging and photovoltaic power production
    Åpne denne publikasjonen i ny fane eller vindu >>On a probability distribution model combining household power consumption, electric vehicle home-charging and photovoltaic power production
    2015 (engelsk)Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 142, s. 135-143Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In this paper we develop a probability distribution model combining household power consumption, electric vehicle (EV) home-charging and photovoltaic (PV) power production. The model is set up using a convolution approach to merge three separate existing probability distribution models for household electricity use, EV home-charging and PV power production. This model is investigated on two system levels: household level and aggregate level of multiple households. Results for the household level show the power consumption/production mismatch as probability distributions for different time bins. This is further investigated with different levels of PV power production. The resulting yearly distribution of the aggregate scenario of multiple uncorrelated households with EV charging and PV power production is shown to not be normally distributed due to the mismatch of PV power production and household power consumption on a diurnal and annual basis.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-243157 (URN)10.1016/j.apenergy.2014.12.031 (DOI)000350935100013 ()
    Tilgjengelig fra: 2015-02-05 Laget: 2015-02-05 Sist oppdatert: 2017-12-05bibliografisk kontrollert
    9. Electric Vehicle Charging and Photovoltaic Power Production from Eight Solar Charging Stations in Sweden
    Åpne denne publikasjonen i ny fane eller vindu >>Electric Vehicle Charging and Photovoltaic Power Production from Eight Solar Charging Stations in Sweden
    2014 (engelsk)Inngår i: 4th Solar Integration Workshop: Proceedings of the 4th International Workshop on Integration of Solar Power into Power Systems, Darmstadt: Energynautics , 2014, s. 425-429Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper quantifies and analyzes data for electric vehicle (EV) charging and photovoltaic(PV) power production from eight charging stations in Sweden withadjacent PV power production provided by Solelia Greentech AB. This study aims toshow the grid interaction of EV charging and PV power production from these solar charging stationswhich are distributed in pairs at four different locations across Sweden. This study utilizesone minute resolution data on power consumption and production from between 281 and310 consecutive days depending on available solar charging station data. Each site, correspondingto two adjacent solar charging stations, has a specific setup regarding EV charging consumer availability.EV charging at two of the sites were available only for the local company/municipality employees and visitors to the company/municipalitywhile the other two sites were public. There was no economical charge for EV charging at any of the stations.Results show that EV charging magnitude and use patterns over timevaried considerably between the stations. Half of the stations had a net consumption of electricityand the other half of stations had a net production of electricity during the metering period.Self-consumption of PV power production was estimated to be between 0.2 and 10 percentdepending on station.

    sted, utgiver, år, opplag, sider
    Darmstadt: Energynautics, 2014
    Emneord
    Elbilsladdning, solelproduktion, dataanalys
    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-236889 (URN)978-3-9816549-0-5 (ISBN)
    Konferanse
    4th International Workshop on Integration of Solar into Power Systems, 10-11 November 2014, Berlin, Germany
    Tilgjengelig fra: 2014-11-25 Laget: 2014-11-25 Sist oppdatert: 2016-05-27bibliografisk kontrollert
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