High Quality Content by WIKIPEDIA articles! Large-scale use of wind power raises many questions in integration into the existing electric power grid. Wind power is an intermittent energy source which must be used when available. If a large fraction of a system`s energy is to come from wind power, provisions must be made to supply load during days with low wind. These provisions might take the form of spinning reserve already allocated in the system, start-up of stand-by power plants, or interconnections to other areas that can take up the load.