Battery Energy Storage System Size Optimization for Energy Shifting and Constant Power Delivery - the Benefits of the System Integration with Solar Farms in Sweden

Abstract

This master's thesis, in collaboration with Comsys AB, examines the optimal size of a Battery Energy Storage System (BESS) for two services - energy shifting and constant power delivery across the four price areas SE1, SE2, SE3, and SE4 in Sweden. For energy shifting applications, the optimal storage capacities were found to be 20 MWh (2 MWh/MW) in SE1, SE2, and SE4. However, a 0.5 MWh/MW storage to power ratio in SE3 was optimal. The energy shifting scenario has a possible market size of 116 40-foot containers, amounting to a market size of $58 million. Under high solar energy penetration scenarios, profitability improved in northern regions. An optimal capacity of 40 MWh (4 MWh/MW) was found for constant power supply, necessitating 397 containers and translating to a market size of $244 million. The study concludes that a 2 MWh/MW ratio for energy shifting and 4 MWh/MW for constant power supply are optimal, suggesting increased solar energy penetration could enhance BESS's financial viability in northern Sweden.

Popular Abstract

This master’s thesis project was carried out in cooperation with Comsys AB to investigate the optimum size of a battery energy storage system (BESS) coupled with a 10 MW solar farm in Sweden. The current transition to renewable energy sources, such as solar, poses new challenges to the power grid. For example, how do we meet the morning and evening high energy demand when the sun shines during the day? This set of opposite patterns creates an imbalance that could have a negative effect on power quality and availability to customers. Battery energy storage system is regarded as one of the best solutions to this problem due to its ability to provide a range of critical services (Stecca et al., 2020). Two of these services were studied in this work, namely energy shifting and constant power supply. The BESS used for energy shifting allows for storing solar energy during low prices and discharging the energy during high price periods (Asian Development Bank, 2018). The low-price periods typically occur at night and around noon when people are at work (low-demand periods). On the other hand, high price periods occur at times when people get ready for work in the morning and when they come home in the evening (Nord Pool | Day-ahead prices). These spot price fluctuations allow shifting energy to the hours when it is the most financially profitable, thus making the system more attractive for investors. At the same time, it allows energy to be stored when there is not as much need for it and discharged when we need it. This helps the system to meet the peak demand and avoid the employment of fossil fuel technologies (Borkowski, Oramus and Brzezinka, 2023). The second studied service - constant power supply- is highly relevant for the future with high solar energy penetration and limited “firm power” supply (e.g., nuclear and fossil fuels). The purpose of BESS in this case is to provide this secure power by storing and discharging the energy in the battery to keep injecting power at a constant level (Tejero-Gómez, 2023). The results for the energy shifting service show that the ideal storage capacity was 20 MWh, thus resulting in the optimum ratio of 2 MWh/MW. For northern regions, the system was not profitable. The energy shifting service was also evaluated for a high solar energy penetration price profile and demonstrated interesting results. The ideal size storage capacity decreased to 15 MWh in northern regions and 5 MWh in southern regions. A significant finding was that northern regions showed increased profitability by 40%, demonstrating that in the future, the BESS system can become attractive for investors even in this part of Sweden. As for the constant power service, the simulations showed a storage capacity of 40 MWh (4 MWh/MW) to be optimal across the whole of Sweden.


References
Bank, A.D. (2018) Handbook on Battery Energy Storage System. Asian Development Bank. Available at: https://www.adb.org/publications/battery-energy-storage-system-handbook (Accessed: 10 April 2024).
Borkowski, D., Oramus, P. and Brzezinka, M. (2023) ‘Battery energy storage system for grid-connected photovoltaic farm – Energy management strategy and sizing optimization algorithm’, Journal of Energy Storage, 72, p. 108201. Available at: https://doi.org/10.1016/j.est.2023.108201.
Nord Pool | Day-ahead prices (no date). Available at: https://data.nordpoolgroup.com/auction/day-ahead/prices?deliveryDate=2024-05-24¤cy=EUR&aggregation=Hourly&deliveryAreas=SE1,SE2,SE3,SE4 (Accessed: 27 May 2024).
Santiago, I. et al. (2021) ‘Classification of Daily Irradiance Profiles and the Behaviour of Photovoltaic Plant Elements: The Effects of Cloud Enhancement’, Applied Sciences, 11(11), p. 5230. Available at: https://doi.org/10.3390/app11115230.
Stecca, M. et al. (2020) ‘A Comprehensive Review of the Integration of Battery Energy Storage Systems Into Distribution Networks’, IEEE Open Journal of the Industrial Electronics Society, 1, pp. 46–65. Available at: https://doi.org/10.1109/OJIES.2020.2981832.
Tejero-Gómez, J.A. (2023) ‘Analysis of Photovoltaic Plants with Battery Energy Storage Systems (PV-BESS) for Monthly Constant Power Operation’, Energies, 16(13), p. 4909. Available at: https://doi.org/10.3390/en16134909.

• author: Situli, Noah and Batkova, Andrea
• supervisor: Max Collins
• organization: Department of Energy Sciences
• course: MVKM05 20241
• year: 2024
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Battery Energy Storage System (BESS), Solar Farm, Energy Shifting, Constant Power Supply, Renewable Energy, Sweden, Energy Demand, Power Quality, Profitability, MATLAB, Size Optimization
• report number: ISRN LUTMDN/TMHP-24/5593-SE
• ISSN: 0282-1990
• language: English
• id: 9166809
• date added to LUP: 2024-07-03 10:20:09
• date last changed: 2024-07-03 10:20:09