A residential community-level virtual power plant to balance variable renewable power generation in Sweden

• Published in: Energy conversion and management 2021-01, Vol.228, p.113597, Article 113597
• Main Authors: Monie, Svante, Nilsson, Annica M., Widén, Joakim, Åberg, Magnus
• Format: Article
• Language: English
• Subjects: Balancing; Cogeneration; Combined heat and power; District heating; Electric power generation; Electric power systems; Electricity; Engineering Science with specialization in Civil Engineering and Built Environment; Flexibility; Heat distribution; Heat exchangers; Heat pumps; Heating systems; Optimization; Peak load; Power balancing; Power consumption; Power plants; Power to heat; Residential areas; Residential communities; Solar power; Teknisk fysik med inriktning mot byggteknik och byggd miljö; Thermal energy storage; Thermal storage; Variable renewable electricity; Virtual power plant; Virtual power plants
• ISSN: 0196-8904; 1879-2227; 1879-2227
• DOI: 10.1016/j.enconman.2020.113597

Power systems with large shares of variable renewable electricity generation, i.e., wind and solar power, require high flexibility in both power generation and demand. Heat pumps and combined heat and power units within district heating systems, and thermal storages have previously been studied for their potential to increase the flexibility of the energy system. When using these technologies for power balancing, they must be operated in a non-standard way with switched merit-order. This study hypothesizes that a residential area could form a local operated entity, i.e., a virtual power plant, that provides power-balancing services to a national power system. The hypothesis is tested with a case-study in Sweden where a combined heat and power unit, heat pumps, a local heat distribution system, and a thermal storage constitute the local entity. A simulation of the energy balances in the system, with optimization of storage size, was performed. The results show that all power surpluses in the system are consumed by the heat pumps. 43% of the annual and 21% of the electricity peak load are covered by the combined heat and power unit. It is concluded that an inter-seasonal thermal storage is crucial for the system's flexibility. Also, large electricity surpluses, if converted to heat and stored, limit the ability of the virtual power plant to utilize the combined heat and power unit for power balancing at a later stage. Despite this, a local virtual power plant can provide increased flexibility by offering power-balancing services to the power system. Attributions: Environment by Felipe Flórez, Solar panels by Adam Terpening, Solar Power by sahua d, Wind Farm by Ron Scott, Power line by Hayden Kerrisk from the Noun Project, https://icon-library.net/icon/hydropower-icon-4.html. [Display omitted] •Thermal storage decouples production from demand and improves temporal flexibility.•Operational strategy of storage affects losses, size and power balancing services.•Sector-coupling of power and thermal energy system improves power balancing.•Heat pumps and thermal storage can aid in decarbonization of the heating sector.•Reduced need for back-up to and required capacity in combined heat and power unit