World’s Largest Thermal Energy Storage Could Heat a City For a Year

By: | April 16th, 2024

Image by Vaanta Energy

From Sunlight to Winter Heat: Finland’s Innovative Vision

Imagine a city that can heat itself for a year, powered by sunshine captured during the summer months. This futuristic vision is about to become a reality in Finland. Vantaa Energy is building the world’s largest thermal energy storage facility, a colossal underground cavern capable of holding a staggering 90 gigawatt-hours (GWh) of thermal energy.

Varanto: Harnessing Nature’s Energy for Year-Round Comfort

This innovation, called “Varanto,” harnesses the power of renewable energy sources. During summer, surplus heat from solar, industrial processes, or other sustainable sources will fill the caverns. These caverns are filled with water, utilizing the naturally insulating properties of the earth to trap the heat for months.

Come winter, when heating demands soar, the stored thermal energy will be released back into the district heating network. The Varanto project involves constructing three caverns, the world’s largest of their kind, over 330 feet underground. These caverns will be filled with hot water using excess renewable energy, including waste industrial heat, maintained at high pressure to prevent boiling. With a total thermal energy capacity of 90 GWh, equivalent to 1.2 million electric vehicles’ energy, the project can meet year-round heating needs.

A Sustainable Shift: Redefining Energy Use in Finland

The Varanto project is a game-changer for sustainable energy. It paves the way for a more balanced as well as reliable energy grid, reducing dependence on fossil fuels and minimizing carbon emissions.

The completion of Varanto in 2028 will be a landmark achievement in the field of thermal energy storage. This Finnish project showcases hope, revealing sustainable energy’s potential for cities around the world.

Nidhi Goyal

Nidhi is a gold medalist Post Graduate in Atmospheric and Oceanic Sciences.

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