FRESNO, Calif. (AP) -- There's a land rush of sorts going on across the nation's most productive farming region, but these buyers don't want to grow crops. They want to plant solar farms.
With California mandating that 33 percent of electricity be generated from renewables by the end of the decade, there are 227 proposed solar projects in the pipeline statewide. Coupled with wind and other renewables they would generate enough electricity to meet 100 percent of California's power needs on an average summer day, the California Independent System Operator says.
And new applications for projects keep arriving.
Developers are flocking to flat farmland near power transmission lines, but agriculture interests, environmental groups and even the state are concerned that there is no official accounting of how much of this important agricultural region's farmland is being taken out of production.
""We've been trying to get a handle on the extent of this for quite a while now," said Ed Thompson of American Farmland Trust, which monitors how much of the nation's farmland is absorbed by development.
The California Department of Conservation, which is supposed to track development on privately held farmland, has been unable to do so because of staff and funding reductions, officials say.
"I'd love to say we have all of that information, but we really don't," said Molly Penberth, manager of the land resource protection division. "We're going to play catch up getting that information, particularly in the San Joaquin Valley."
Planning department records in four of the valley's biggest farming counties show about 100 solar generation plants already proposed on roughly 40,000 acres, or about the equivalent of 470 Disneyland theme parks. Planners in Fresno County say their applications for solar outnumber the ones they received for housing developments during the boom days.
Solar developers have focused on the southern San Joaquin Valley over the past three years for the same reason as farmers: flat expanses of land and an abundance of sunshine. Land that has been tilled most often has fewer issues with endangered species than places such as the Mojave Desert, where an endangered tortoise slowed solar development on federal land.
Much of the solar development is proposed for Kern, Tulare, Fresno and Kings counties, which are home to more than 400 crops that pump $30 billion into the economy and help sustain U.S. food security.
In January, the farmland trust released a report projecting that by 2050 more than 570,000 acres across the region could be lost to development as the Central California population explodes. Farmland losses due to housing, solar development, a warming climate, cyclical drought and ongoing farm water rationing to protect endangered fish, plus the state's signature transportation project -- the High Speed Rail -- are all issues the trust is trying to monitor.
"These are things that don't make headlines, but come under the category that you don't know what you've got until it's gone," Thompson said.
No statewide plan or policy exists to direct projects to areas where land is marginal for farming and power transmission lines exist or can be easily routed, though groups as diverse as the Defenders of Wildlife and the independent state oversight agency Little Hoover Commission have issued studies calling for one.
Projects are approved by elected county boards of supervisors, or if larger than 50 MW, the California Energy Commission.
"There's no consistent approach" county to county in deciding what gets approved on farmland, said Kate Kelly, a planning consultant who is studying the environmental impact of valley projects for Defenders of Wildlife.
While one of the nation's leading solar trade groups has not taken an official position on conversion of farmland to solar, Katherine Gensler of the Solar Energy Industries Association says more thought must go into location.
The largest solar facility operating so far covers 500 acres 60 miles northwest of Bakersfield and produces enough electricity for 36,000 homes.
Just three weeks into 2013, five valley farmers have told the Department of Conservation that they want to cancel low agriculture tax rate contracts to develop solar on their property. None takes advantage of a year-old law making it easier to cancel on marginal land, Penberth said.
County boards of supervisors are attracted to the promise of clean energy construction jobs. Some of the projects are on prime land as small as 20 acres, some on habitat shared by threatened or endangered species such as the kit fox, Swainson's hawk and blunt nose lizard. The 9,000-acre Maricopa Sun project in western Kern County is on prime land that the county says lacks a reliable water supply.