net nl | Subterranean heat storage

EcovatIn the media

From Tesla’s Powerwall to Enexis’ Buurtbatterij: energy storage is hot. But there are other means than storage in batteries also. For instance Ecovat’s subterranean heat storage system.

Less CO2 emissions

Managing director Aris de Groot: “Solar and wind energy create instability in the electricity grid. Our system stores surpluses of sustainably generated energy underground, ready for use later on. Consequently, households have sufficient clean energy at their disposal all the year round, which enables them to reduce the use of fossil fuels – and therefore their carbon emissions – to zero.”


“Ecovat uses local (residual) heat and power-to-heat. When wind turbines generate more energy than required for a while, the surplus power can be used for heating the water in an underground storage tank. The buffer water can reach temperatures of up to 95 degrees Celsius.”

Close to home

“Although the sustainably generated electricity may come from afar, e.g. from the sea, the tank should be placed underground in close proximity to the houses that require heating. Otherwise too much power loss will occur. The surrounding area is hardly affected. Nature above the ground can be kept intact or you can build a car park on it.”

Everything balanced

“The most important advantage of heat storage is that no renewable energy is lost. Wind turbines and solar panels can continue to generate energy during times of overproduction. But that is not all. Energy generated in summer often is quite a bit cheaper than when generated in winter. By storing it, not only the grid, but also the price is balanced better.”

Cooperation network administrators

“For a network administrator this innovation is interesting, because it can lower the strain on the grid. That is why the cooperation with network administrators is so important. They have a good idea of when supply and demand will peak, and whether or not there is enough margin on the grid. We can play along with this, using our system.”

net nlThis article appeared in the spring edition of net NL, the quarterly magazine issued by Netbeheer Nederland. The complete magazine can be viewed here.