Stefan Quandt, the billionaire behind BMW, is quietly investing in battery technology. According to Bloomberg, Quandt invested in Solarwatt, a company that lets customers store electricity they generate from their solar panels in a battery. Battery systems let customers store electricity generated during the day for when they need it. They essentially allow homes and business to be less dependent on the grid.

Tesla is also working on a similar technology. Earlier this year, Elon Musk – Tesla’s CEO – unveiled Tesla Energy and the Tesla Powerwall, a home battery pack which can store energy in a far more efficient and economic manner than the conventional battery. The Tesla Powerwall charges itself using solar power but can also draw power from the grid as well.

As more people disconnect from the grid, the electricity prices are likely to go up which would encourage remaining customers to follow the renewable energy movement.

There is still a lot of work to do in the U.S. as well, where many states provide no incentive for customers to store energy rather than return it to the grid.

At the opposite end of spectrum is Germany which has more installed solar panels than any other country and subsidies for returning unused solar power to the grid are dropping.

Helped by government subsidies, 4,500 residential battery storage systems were sold in Germany in the third quarter, more than double the year earlier period, according to Bloomberg New Energy Finance.