As more solar and wind power comes on line, it becomes increasingly difficult, and expensive, to ensure stability of the grid. Intermediate energy storage is therefore rapidly becoming an essential tool to keep power fluctuations on the grid within manageable limits. Moreover, as feed-in tariffs are decreasing, the business case for a home energy storage system that increases self-consumption becomes more solid every day. Intermediate energy storage increases self-consumption of harvested solar and/or wind power. The natural next step is 100% self consumption and independence from the grid.