According to research by the Berkeley Lab, "The price of electricity sold to utilities under long term contracts from large-scale solar power projects has fallen by more than 70 percent since 2008, to just $50/MWh on average within a sample of contracts signed in 2013 or 2014 and concentrated among projects located in the southwestern United States."
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The performance of the PV plants backed by the Obama administration should give investors confidence that production targets can be met. Take the case of California Valley Solar Ranch, owned by NRG Energy and built using SunPower technology. On the broad, sunny Carrizo Plain in inland San Luis Obispo County, the 250-MW plant was expected to produce 662,000 MWh of electricity annually, on average, for buyer Pacific Gas & Electric. In fact, in its first full year of operation – the 12-month period through September 2014 – it generated 697,759 MWh, according to EIA data.
California Valley Solar Ranch cost $1.6 billion to build, with $1.2 billion coming through the U.S. Department of Energy's 2009 stimulus-enhanced guaranteed loan program. But that same plant today would certainly be less expensive, perhaps dramatically less expensive. For example, a nearly identical plant proposed to be built about 100 miles north of California Valley Solar Ranch – it would be 247 MW in size and produce 666,000 MWh annually, according to a power purchase agreement with Southern California Edison – will reportedly cost $600 million.
—Pete Danko, Breaking Energy