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  • 1.
    Flygare, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Jonasson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Castellucci, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Correlation as a method to assess electricity users' contributions to grid peak loads: A case study2024In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 288, article id 129805Article in journal (Refereed)
    Abstract [en]

    Flexibility has increasingly gained attention within the field of electrification and energy transition where a common objective is to reduce the electricity consumption peaks. However, flexibility can increase the risk of grid congestion depending on where and when and it is used, thus an overall system perspective needs to be considered to ensure an effective energy transition. This paper presents a framework to assess electricity users' contributions to grid load peaks by splitting electricity consumption data into subsets based on time and temperature. The data in each subset is separately correlated with the grid load using three correlation measures to assess how the user's consumption changes at the same time as typical grid peak loads occur. The framework is implemented on four different types of business activities at Uppsala municipality in Sweden, which is a large public entity, to explore their behaviors and assess their grid peak load contributions. The results of this study conclude that all four activities generally contribute to the grid peak loads, but that differences exist. These differences are not visible without splitting the data, and not doing so can lead to unrepresentative conclusions. The presented framework can identify activities that contribute the most to unfavorable grid peaks, providing a tool for decision-makers to enable an accelerated energy transition.

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  • 2.
    Hjalmarsson, Johannes
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Lindberg, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering, Civil Engineering and Built Environment.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Carlsson, Fredrik
    Vattenfall R&D.
    Enhancing the value of large-scale energy storage systems in congested distribution grids using service stacking2023In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538Article in journal (Other academic)
    Abstract [en]

    Energy storage systems (ESS) are suitable for many grid applications, where some have large seasonal variations. By combining additional services, i.e., service stacking, companies with energy storage assets may generate additional revenue as well as provide services to the power system. This paper aims to highlight and estimate the technical and economic potential of stacking services using energy storage systems in congested a distribution grid. A scheduling optimization tool was implemented for a large-scale battery ESS providing a selection of deemed relevant services over two years. The results show that there is a great potential to enhance the value of the ESS significantly depending on the service portfolio layout. A capacity life loss model was also implemented to analyse the degradation of the ESS, and the cycle aging was estimated for the chosen portfolios. The results showed that a fully stacked portfolio does not necessarily result in increased cycle aging, but that it depended on the services in the portfolio. The cycle aging was affected the most by stacking flexibility with energy arbitrage, while frequency regulation services only resulted in a few additional cycles during each year of operation. 

  • 3.
    Hjalmarsson, Johannes
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Carlsson, Fredrik
    Vattenfall R&D.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Evaluation of centralized and distributed energy storage systems in congested distribution grids with service stacked portfolios2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118Article in journal (Refereed)
    Abstract [en]

    The clean energy transition is expected to continue at a fast pace in the upcoming years and will imply connection of large amounts of distributed energy resources to existing distribution grids. These have the opportunity to support the power system both locally but also regionally and possibly on a system level too, which could be achieved by bundling services i.e., service stacking. The aim of this article is to compare effects on distribution grids when implementing service stacked portfolios for centralized and distributed storage capacities in congested distribution grids. The complex nature of the scheduling optimization problem motivated using a non-linear solver and for this study a meta-heuristic approach was chosen. A large number of energy storage units were connected to the IEEE European Low Voltage test feeder and load flow calculations were executed using the open-source distribution grid simulator OpenDSS. The results indicate that service stacking could be implemented successfully for both centralized and distributed storage capacities, but the possibility to target local and regional power quality measures varies for the two cases. Finally, multi-service provision using energy storage systems should be considered in more extensive simulation and real-world studies to fully capture the effects on grid dynamics and scheduling possibilities. 

  • 4.
    Hjalmarsson, Johannes
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Carlsson, Fredrik
    Vattenfall R&D.
    Optimal scheduling of energy storage system in distribution grids using service stacking2023In: 27th International Conference on Electricity Distribution (CIRED 2023), Institution of Engineering and Technology, 2023, p. 3077-3081Conference paper (Refereed)
    Abstract [en]

    Energy storage systems are widely used for power system applications. By implementing service stacking, enhanced performance of storage systems can potentially be obtained. A scheduling tool based on linear programming was implemented to schedule a grid connected energy storage for two portfolios in separate periods. The results show that it is possible to provide additional services which generate value to the power system. By implementing a capacity loss life model the increased cycle aging is estimated. 

  • 5.
    Hjalmarsson, Johannes
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Carlsson, Fredrik
    Vattenfall R&D.
    Scheduling optimization of stacked grid services using energy storage system at large sport facilities in a congested distribution grid2023In: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538Article in journal (Refereed)
    Abstract [en]

    Congestion management in distribution grids is a growing challenge for network operators due to a combination of fast growing cities and electrification of transport and industry sectors. Energy storage systems connected downstream of bottlenecks have the potential to relieve parts of the peak demand, and typically does not motivate investments financially as a third-party actor alone. By stacking services it is possible for storage units to become financially viable while also enabling opportunities for providing additional local services and participation in markets for ancillary services. In this study, a large customer connected to the congested distribution grid in Uppsala, Sweden, was considered and the systematic potential of a battery connected to the facility was evaluated. A set of portfolios including the services tariff optimization, flexibility-as-a-service, and frequency containment reserve was evaluated by finding the optimal scheduling strategy using a metaheuristic optimization approach together with a capacity loss life model. The analysis was done for two separate years to illustrate the impact of yearly market fluctuations on the service allocation. Additionally, a sensitivity analysis was also performed for the rated energy capacity of the battery. The simulation results indicate that stacking services yields the most valuable portfolio with respect to both technical and economic value where the battery managed to capture several revenue streams at the cost of a small increase in cycle aging, compared to when using the BESS for tariff optimization only. From a system perspective, stacking services enables the BESS to support the power system and the local distribution grid during a large majority of the year. 

  • 6.
    Wallberg, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Waters, Rafael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Castellucci, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Peak Shaving for Electric Vehicle Charging Infrastructure: A Case Study in a Parking Garage in Uppsala, Sweden2022In: World Electric Vehicle Journal, ISSN 2032-6653, E-ISSN 2032-6653, Vol. 13, no 8, article id 152Article in journal (Refereed)
    Abstract [en]

    The need for a more flexible usage of power is increasing due to the electrification of new sectors in society combined with larger amounts of integrated intermittent electricity production in the power system. Among other cities, Uppsala in Sweden is undergoing an accelerated transition of its vehicle fleet from fossil combustion engines to electrical vehicles. To meet the requirements of the transforming mobility infrastructure, Uppsala municipality has, in collaboration with Uppsala University, built a full-scale commercial electrical vehicle parking garage equipped with a battery storage and photovoltaic system. This paper presents the current hardware topology of the parking garage, a neural network for day-ahead predictions of the parking garage’s load profile, and a simulation model in MATLAB using rule-based peak shaving control. The created neural network was trained on data from 2021 and its performance was evaluated using data from 2022. The performance of the rule-based peak shaving control was evaluated using the predicted load demand and photovoltaic data collected for the parking garage. The aim of this paper is to test a prediction model and peak shaving strategy that could be implemented in practice on-site at the parking garage. The created neural network has a linear regression index of 0.61, which proved to yield a satisfying result when used in the rule-based peak shaving control with the parking garage’s 60 kW/137 kWh battery system. The peak shaving model was able to reduce the highest load demand peak of 117 kW by 38.6% using the forecast of a neural network.

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    fulltext
  • 7.
    Castellucci, Valeria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flygare, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Potential of Load Shifting in a Parking Garage with Electric Vehicle Chargers, Local Energy Production and Storage2022In: World Electric Vehicle Journal, ISSN 2032-6653, E-ISSN 2032-6653, Vol. 13, no 9, article id 166Article in journal (Refereed)
    Abstract [en]

    The electrification of the transport sector is of crucial importance for a successful transition to a fossil-free society. However, the electricity grid constitutes a bottleneck. This article provides a case study based on a real-world parking garage with a smart grid infrastructure, called Dansmästaren. The analysis shows how renewable energy sources, energy storage technologies, and smart charging of electric vehicles can smooth out the load curve of the parking garage and relieve the electric grid during peak hours. Dansmästaren is located in Uppsala, Sweden, and equipped with 60 charging points for electric vehicles, a PV system, and a battery storage system. The study utilizes an energy flow model to show the potential of a realistically dimensioned smart energy system, that can benefit the parking facility in itself and the local distribution grid in a city, Uppsala, with grid capacity challenges. The results suggest that the parking garage demand on the local grid can be significantly lowered by smarter control of its relatively small battery energy storage. Moreover, further smart control strategies can decrease demand up to 60% during high load hours while still guaranteeing fully charged vehicles at departure in near future scenarios. The study also shows that peak shaving strategies can lower the maximum peaks by up to 79%. A better understanding of the potential of public infrastructures for electric vehicle charging helps to increase knowledge on how they can contribute to more sustainable cities and a fossil-free society.

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    fulltext
  • 8.
    Flygare, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Wallberg, Alexander
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Hjalmarsson, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Fjellstedt, Christoffer
    Aalhuizen, Christoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Castellucci, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    The potential impact of a mobility house on a congested distribution grid – a case study in Uppsala, Sweden2022In: CIRED Porto Workshop 2022: E-mobility and power distribution systems, London: IEEE, 2022, article id 1442Conference paper (Refereed)
    Abstract [en]

    The distribution grid in Uppsala, Sweden, has during the last years experienced an increasing number of hours with congestion, and as the city and number of EVs are growing new solutions are needed to not worsen this problem. Uppsala Municipality is planning a series of so-called “mobility houses” which will act as a hub for transportation while, at the same time, supporting the transition to a fossil-free energy system. Dansmästaren – the first mobility house in Uppsala – was built in 2020 and this paper describes its parking garage's main energy system parts, giving a brief introduction and analysis of each and their potential effect on Dansmästaren's grid impact. Dansmästaren has the potential to control its load on the grid, but it is essential to collect more data and analyze when flexibility is of most importance. Future studies suggest analyzing Dansmästaren's systems in more detail and developing a more advanced energy management system.

1 - 8 of 8
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