Diablo Canyon Power Plant is on approximately of land located just west of Avila Beach, California. The power-producing portion of the plant occupies around . Together, the twin 1100 MWe reactors produce about 18,000 GW·h of electricity annually (8.6% of total California generation and 23% of carbon-free generation), supplying the electrical needs of more than 3 million people. Though it was built less than a mile from the Shoreline fault line, which was not known to exist at the time of construction, and is located less than three miles from the Hosgri fault, a 2016 NRC probabilistic risk assessment of the plant, taking into account seismic risk, estimated the frequency of core damage at one instance per 7.6 million reactor years.