In April 2011, Governor Brown signed a bill requiring one-third of California's energy to be produced from renewable sources by December 31, 2020. This energy mandate has created a land rush, and developers and utilities are scrambling to acquire the 100,000 acres of land needed to accommodate the number of photovoltaic solar arrays necessary to satisfy the mandate. Much of the land most desirable for development of utility-scale photovoltaic solar facilities is agricultural land subject to Williamson Act contracts.

The Williamson Act allows landowners and cities or counties to enter into agreements restricting private land to agricultural, open space, or other compatible uses for a period of at least ten years. In exchange for the conservation of agricultural and open space lands, landowners receive a lower assessed value for their property taxes based on the land's restricted use, as opposed to its unrestricted fair market value. Currently, 16.6 million acres of land are encumbered by Williamson Act contracts.