IBM’s Jennifer Potter published a post about energy storage and the possible benefits for utilities:
Tesla’s Powerwall Home Battery seems poised to wean consumers off the big grid. A recent TechCrunch article claims that a single battery pack, valued at $3,000, will let a household run entirely on solar energy. On the other hand, Wired’s Rhett Allain challenges these claims by explaining the physics of energy storage. According to Allain, a single 10 kWh Powerwall could not meet the electricity demands of a typical household. Surveys conducted by the U.S. Energy Information Administration average typical household use at 30 kWh a day, therefore, a customer would need three Powerwalls to stay off the grid entirely.
Three powerwalls can be arranged, but this would only work for sunny states and countries. I don’t think that west- and nordic European countries have enough sunshine in the winter to even supply themselves with solar power.