Tesla Motors battery to be used to store commercial solar energy

New York Times : One of the problems facing companies that install solar panels on commercial buildings is finding a way to satisfy the buildings’ power needs during high demand periods or when the Sun is not shining. One such company, SolarCity, has decided to use the automobile battery packs developed by Tesla Motors. The refrigerator-sized batteries are paired with a control system that alternately draws power from the solar panels, the batteries, or the external power grid, depending on current supply and demand. By having stored energy available at peak usage times, buildings could draw less energy from the grid, thereby reducing their overall electrical costs. Whether the system will end up being cost-effective will depend on local electricity costs and federal tax credit eligibility. SolarCity will begin installing the systems for businesses in three states and also for about 300 residential customers.