The Ivanpah Solar Electric Generating System, located near the California-Nevada border, burst into flames when some of the thousands of mirrors that focus sunlight on water towers became misalinged and started an electrical cable fire. 

The plant was built with a $1.6-billion taxpayer-guaranteed loan and is run by a consortium of companies that include BrightSource Energy, NRG Energy, and Google.

Associated Press:

Firefighters had to climb some 300 feet up a boiler tower at the Ivanpah Solar Electric Generating System in California after fire was reported on an upper level around 9:30 a.m., fire officials said.

The plant works by using mirrors to focus sunlight on boilers at the top of three 459-foot towers, creating steam that drive turbines to produce electricity.

But some misaligned mirrors instead focused sunbeams on a different level of Unit 3, causing electrical cables to catch fire, San Bernardino County, California fire Capt. Mike McClintock said.

avid Knox, spokesman for plant operator NRG Energy, said it was too early to comment on the cause, which was under investigation.

The fire was located about two-thirds of the way up the tower, said Jeff Buchanan of Nevada's Clark County Fire Department, which also responded to the blaze.

Plant personnel had the fire out by the time firefighters reached the spot, and it was officially declared out in about 20 minutes.

Photos showed melted and scorched steam ducts and water pipes.

Knox said the tower was offline while crews assess the damage. He could not immediately say when it would restart.

The plant can produce enough power for 140,000 California homes, but a second tower is shut down for maintenance, leaving only one running.

It was not immediately clear what impact that would have on California's electricity supply.

Ivanpah has been plagued with troubles since the beginning.  It has failed to meet production targets, generating only about 75% of the power that was promised.  It also regularly incinerates birds and blinds pilots as the mirrors reflect sunlight.

Bird Smoked at Ivanpah - Probably dies. from Norman Rogers on Vimeo.

And the energy it does produce is incredibly expensive – $200 per megawatt-hour, which is nearly six times the cost of electricity from natural gas-fired power plants. 

A boondoggle, to be sure.  There's also a question of whether such industrial-sized plants can operate safely and reliably.

Solar panels on your roof are harmless and may cut your electricity bill.  But 300,000 mirrors focusing the awesome power of the sun on water tanks are expensive to build and operate and may end up costing electricity consumers more than fossil fuel plants.  As we now see, it doesn't take much to shut them down and drastically affect power generation.

Ivanpah is called a "demonstration project."  About the only thing it's demonstrating is that its benefits have been overpromised and its perils underreported.