Northern locales though have a much greater energy need for heating in the winter. So the "battery" solutions can often just be cheap heat batteries because there is not so much a thing as "waste heat" - that heat can be used directly without worrying as much about efficiency losses in conversion.

There are already a bunch of examples of Northern locales using these heat batteries - just heat up a big block of something when energy is cheap and solar/wind are overproducing, then use a network of insulated pipes to distribute that heated water.