EPV Energy’s subsidiary Vaasan Voima has made a major investment decision concerning the development and increased flexibility of its thermal energy storage processes in Vaskiluoto. The investment will raise the temperature of the TES facility from the current 95 degrees Celsius to above boiling point by utilising the static pressure created by the column of water. The raise in temperature will increase the total capacity of the TES facility by more than 50% to 17 gigawatt-hours. The investment also includes a new 60 MW electric boiler suitable for steam production, an upgrade of the process network serving the system with higher temperatures, and a buffer tank.
The Finnish Ministry of Economic Affairs and Employment has granted the project NextGenerationEU funding of EUR 5,815,240. The total investment in the project is more than EUR 20 million, including the electric boiler which falls outside the funding.
Janne Österback, Managing Director of Vaasan Voima, couldn’t be more pleased about the investment decision. According to him, the expansion of the TES facility will raise heat production in Vaskiluoto to a whole new level.
“The temperature increase will allow non-combustion energy to be stored and delivered to customers throughout the winter, even in the coldest months. The capacity increase will significantly improve our production flexibility and enable us to store larger amounts of renewable energy than ever,” Österback explains.
This TES facility expansion was one of 13 projects that were awarded NextGenerationEU funding by the Ministry of Economic Affairs and Employment. Vaasan Voima’s share was the largest of all the energy infrastructure and electrification projects included.
“The fact that we were awarded such a large amount of investment aid emphasises the importance of this development trend for society and the significance of the project’s uniqueness and innovation. The investment will enable us to use broad sector coupling and increase our zero-emission production of district heating,” Österback continues.
Sector coupling brings more flexibility to heat production
Increasing the temperature and capacity of the thermal energy storage facility will create new opportunities to optimise the existing energy production. It will enable emission reductions and diversify the company’s ability to operate in the fast-changing energy market. The 60 MW electric boiler, that is part of the investments, is the fourth one added to the Vaskiluoto power plant.
The investment project will double the charging and discharging capacity of the TES facility, achieving an impressive 220 megawatts. Österback explains that this change in the process will enable the separation of heat production and the supply of district heating, creating more security and opportunities for both the producer and the customer.
“In the future, our heating customer Vaasan Sähkö will be able to better optimise their needs, while we at Vaasan Voima will also be able to optimise our production more flexibly as the situation demands. The supply of non-combustion-based district heating will be better secured in the future, regardless of potential disruptions in the electricity market. In terms of strategy, this will enable both EPV and Vaasan Sähkö to further reduce their emissions in energy production,” he says.
Expanded TES facility to be completed next year
The TES facility expansion project will be launched this autumn, with an estimated total project timeframe of about one year. The plans make use of already existing structures as far as possible. The trial operation of the upgraded TES facility is scheduled to start towards the end of 2025.
“The project will not affect the use of the TES facility and it will cause no interruptions to the production of heat,” Österback says.
The project as a whole, including the new buildings and equipment required, will be located on the Vaskiluoto power plant site.
From an oil storage area to an energy reserve
The increase in the facility’s thermal storage capacity is a continuation of the development work carried out in Vaskiluoto in previous years. The TES facility was originally introduced in 2020 and since then, Vaasan Voima has carried out significant development work to the facility and the use of renewable energy as part of its district heat production.
Development of production solutions in Vaskiluoto:
2020: The old oil storage facilities in Vaskiluoto are converted for thermal storage. Storage capacity 7 GWh.
2021: The first sector coupling solution using a 40 MW electric boiler.
2023: The TES facility’s expansion cavern is put into storage use, increasing the company’s thermal storage capacity to 11 GWh. Sector coupling capacity is quadrupled with the addition of a 120 MW electric boiler.
2024: A pressure reduction station for the main boiler is introduced, enabling more efficient production of heat using combustion technology. It also allows the company to participate more flexibly in the opportunities existing in a volatile electricity market.
2025: The capacity of the Vaskiluoto TES facility will be increased to 17 GWh by increasing its temperature. A fourth electric boiler will be installed in Vaskiluoto, bringing the total capacity of the electric boilers to 220 MW. The investment will raise sector coupling and thermal energy storage technology to a whole new level.
Over the last few years, EPV Energy’s main focus in developing its sector coupling and thermal energy storage has been to improve its operational flexibility. The latest investment will significantly increase this flexibility, while at the same time enabling the company to increase the relative share of renewable energy in its heat production. Carbon-neutral generation and flexibility are at the heart of EPV’s New Electricity Revolution strategy, and we will continue to invest in these.
