Lakes Solar: Many people who have Solar Electricity generation on their roofs make more than they need in the middle of the day and at the moment most people sell the excess back to the Electricity Supplier's grid. There is usually a big price difference between what the company sells you electricity, and how much they are willing to pay you for your excess electricity. Usually you are charged around 36cents for a KiloWattHr but they only pay you 6cents for energy you create.
If you store your excess electricity in a battery, you can use it later in the day when your base load exceeds the power being generated by the Solar Panels. This means all the power your panels produce is worth 36cents, a 600% increase in the worth of your excess solar power!! Fronius provide superb systems that cater for domestic totally isolated, "off the grid" setups, to full three phase maximum domestic generation, through to fully engineered industrial/commercial set ups.