Significant climate benefits from seasonal heat storage
The world’s largest seasonal heat storage facility is being designed for Kuusikonmäki in Vantaa to store heat from renewable energy sources. The seasonal heat storage facility is expected to be completed in 2026. It would make it possible for Vantaa Energy to phase out fossil fuels in energy production when thermal energy produced from renewable energy sources in the summer season can be stored and used in the cold winter periods. The seasonal heat storage will promote many of the EU’s climate targets and improve the security of district heat supply as it will provide heating capacity that is does not rely on power plants.
In seasonal heat storage, renewable energy from, e.g. solar, wind and waste heat sources is stored in water with a temperature of 140-150 degrees. The capacity of the seasonal heat storage facility of one million cubic metres is 90 gigawatt-hours, corresponding to the annual heat demand of an average Finnish town.
“The environmental benefits of seasonal heat storage are significant. As a result of the facility, Vantaa Energy will be able to phase out the use of fossil fuels by 2026 as the energy obtained from renewable energy sources in the summer season can be stored and used in the cold winter periods when the heat demand is higher. Heat energy stored in the facility will fully replace the use of natural gas in the winter season. Phasing out fossil fuels also means that after 2026 the heating in Vantaa will, in practice, be based on heat produced from domestic energy sources because phasing out fossil fuels also means abandoning imported fuels at the same time. That way, the seasonal heat storage will reduce dependency on imported fuels in Vantaa and, more extensively, in the whole of Finland. The seasonal heat storage facility will also make it possible to take into account various needs of the customers: waste heat created in other customer sites, for example, in shops, can be collected into the facility and transferred, for example, to personal customers during periods of high heat demand, e.g. for heating homes via the heating network,” explains Business Development Manager Matias Siponen.
The seasonal heat storage facility will reduce carbon dioxide emissions from heat production by 65,000 tonnes per year. The facility will improve the security of district heat supply because there will always be available heating capacity that is not dependent on power plants. The seasonal heat storage capacity will also help to achieve Vantaa Energy’s target of energy production without fossil fuels in 2026 and also the carbon neutrality target of the City of Vantaa in 2030. When the use of fossil fuels has ended by 2026, Vantaa Energy will continue its progress towards carbon negativity in 2030.
The seasonal heat storage will promote several of the EU’s other climate and energy targets: it will boost resource efficiency based on strong utilisation of waste heat, increase the share of renewable energy forms in energy production, and accelerate the integration of different energy systems. The plan of the seasonal heat storage can be duplicated, and therefore its technical solution could help energy systems to disengage from fossil fuels also elsewhere in Europe. The technical solution of the seasonal heat storage facility and the expertise related to its design may also be a significant export product to other countries.
The seasonal heat storage facility is designed and built with an alliance model where YIT is responsible for the construction, AFRY for the design and Vantaa Energy is the client. All of them also work in partnership across organisational boundaries.
Matias Siponen, Business Development Manager, Vantaa Energy Ltd
tel. +358 50 494 6115