ABSTRACT
Wind and photovoltaic (PV) power systems have made a successful transition from small stand-alone sites to large grid-connected systems. The utility interconnection brings a new dimension to the renewable power economy by pooling the temporal excess or the shortfall in the renewable power with the connecting grid that generates base-load power using conventional fuels. This improves the overall economy and load availability of the renewable plant site — the two important factors of any power system. The grid supplies power to the site loads when needed or absorbs the excess power from the site when available. A kilowatthour meter is used to measure the power delivered to the grid, and another is used to measure the power drawn from the grid. The two meters are generally priced differently on a daily basis or on a yearly basis that allows energy swapping and billing the net annual difference.
