A vast “thermos” that will store millions of gallons of hot water to help heat homes in Berlin this winter has been unveiled.
The huge insulated water tank located at the Reuter power station uses excess electricity from solar and wind power plants across Germany.
The head of Swedish utility company Vattenfall’s heat unit in Germany said that the facility can help smooth out the fluctuating energy provided by renewables while providing reliable heat to hundreds of thousands of households.
The 52 million dollar tower will be Europe’s biggest heat storage facility when it is completed at the end of this year, and even bigger one is already being planned in the Netherlands.
With a height of almost 150 feet and holding up to 14.8 million gallons of hot water, Vattenfall said the tower will help heat Berlin homes this winter even if Russian gas supplies dry up.
“It’s a huge thermos that helps us to store the heat when we don’t need it,” said Tanja Wielgoss, who heads the Sweden-based company’s heat unit in Germany. “And then we can release it when we need to use it.”
While district heating systems fuelled by coal, gas or waste have been around for more than a century, most are not designed to store significant amounts of heat.
By contrast, the new facility unveiled on Thursday will hold water brought to almost boiling temperature with excess electricity from plants across Germany.
“Sometimes you have an abundance of electricity in the grids that you cannot use anymore, and then you need to turn off the wind turbines,” said Wielgoss. “Where we are standing we can take in this electricity.”
The facility will have a thermal capacity of 200 Megawatts – enough to meet much of Berlin’s hot water needs during the summer and about 10% of what it requires in the winter.
The vast, insulated tank can keep water hot for up to 13 hours, helping bridge short periods when there is little wind or sun.
It will also be able to use other sources of heat – such as that extracted from wastewater, said Ms Wielgoss.
Berlin’s top climate official, Bettina Jarasch, said the faster such heat storage systems are built, the better.
“Due to its geographic location the Berlin region is even more dependent on Russian fossil fuels than other parts of Germany,” she said.
“That’s why we’re really in a hurry here. The war in Ukraine and the energy crisis teach us that we need to be faster.
“First of all to become climate neutral. And secondly, to become independent.”