They are building one in Finland that is 90 GWh with simple technology! That would be an absurd project with current electric batteries. It’s a lot of easier to

They are building one in Finland that is 90 GWh with simple technology! That would be an absurd project with current electric batteries. It’s a lot of easier to scale a big insulated pool of water or sand and heat it up with any waste heat and energy through the year. Only works for heating but many places need heating