Evergreen Solar – The solar photovoltaic cells in your solar panels are the mechanisms which convert sunlight into energy. When you install solar panels on your house, the PV cells convert sunlight into direct current (DC) and an inverter connected to the system is what converts direct current into alternating current (AC) – which is the type of current needed to power your household appliances. This power runs through your electrical panel box, just like electricity you get from the grid, and you can potentially run your entire house on solar power than power taken from the grid.
Most residential solar energy systems are still connected to the grid. This is to allow for uninterrupted electricity in occasions when you don’t have enough solar energy to continue to power your house (e.g., on cloudy days or during the night).
If you generate enough energy from your solar panels such that you have “extra” energy left over, it will get fed back to the grid and you will get credit for this contribution of energy. Termed “net metering,” this transfer of electricity allows some customers to still maintain a $0 electric bill even when using the utility company’s energy from the grid. more> evergreensolar.com