It’s early morning as I speed down California’s Interstate 5 and head south to the Central Valley, a region known for political battles over energy. On one side of the freeway, transmission lines run along the spines of rolling hills. On the other side, the California Aqueduct snakes through fertile land to deliver water to hydroelectric power plants, farms and cities.
My destination is Chevron’s oldest oil field in California, located near the town of Coalinga, which has a population 18,000 and gets its name from having been a coal supply depot for trains that ran on coal-generated steam power. I’m visiting the oil field to check out a project that is demonstrating a way to use the sun’s energy to produce steam to increase oil production. Chevron pipes steam down the wells to pry loose oil that is stuck in rock fissures and this makes it easier to pump the oil back to the surface (see my photo slide below).
Where fossil fuels and solar power meet
BrightSource Energy, which counts Chevron as an investor, built the project and completed it last fall. The 29 MW project includes a field of 3,822 heliostats – each of which is made up of two, 10-foot by 7-foot mirrors – on 65 acres (the entire project takes up 100 acres). The mirrors track the sun’s movement to direct sunlight onto a series of panels containing water pipes at the top of a 327-foot tower.
The sun’s energy heats the water to generate steam that reaches 700 degrees Fahrenheit, says Ray Guidry, a construction supervisor from Chevron Technology Venture who shows me and other visitors around the solar mirrors and takes us up to the tower for a close look at the steam production system. The steam goes to a heat exchanger near the bottom of the tower to transfer that heat to another water-containing pipe to generate the steam that then fans out across the oil field.
Cleantech proponents may not see oil production as an ideal use of solar energy. They probably would much prefer the world to cut its reliance on oil and other sources of fossil fuels. But Chevron isn’t running the solar steam project to earn good will from its critics. The company sees solar steam as a potentially good alternative for oil fields that don’t have ready access to natural gas because of their locations or geopolitics.
Certainly, if natural gas prices go up significantly, then a solar steam project also could become a cost-effective choice. For now, natural gas is cheap and Chevron actually produces most of the natural gas it needs for its Coalinga operation from the Coalinga oil field.
No solar for you
With rain in the morning in the San Francisco Bay Area and big pillows of clouds over Coalinga when I arrive, it becomes clear that the day isn’t ideal for seeing the solar field in action. The wind is kicking up and is set to really blow after dark, so most of the mirrors are in a rest position that places them parallel to the ground. The spot atop the tower that would normally shine brightly from being a receiver of the concentrated sunlight is dark.
“The rule of thumb is if you can’t see your own shadow, then you can’t” put the solar mirrors to work, Guidry says as we stand amid a forest of heliostats.
Guidry wants to show us the mirror washing equipment. Some of the mirrors already are perpendicular to the ground and ready for a mop down. Fine dust coasts the mirrors, requiring them to be cleaned. A big truck rolls toward us as it tackles each mirror with a big roller brush.
Chevron has only been operating the solar field for about seven months, so the company is in the early days of collecting field data to see if the technology will perform as promised. How often the mirrors should be cleaned is one of the questions that the field data will help answer – the current estimate is once a month.
So far, the field is producing 10 percent more steam than what the company expects based on its daily performance model, Guidry says. BrightSource took on the project knowing it would incur losses, but it accepted the contract to showcase its technology anyway because the project was to be its first installation in the United States. But the company ended up losing more money than it anticipated in 2008, when it thought the losses would amount to $10.5 million. The figure actually reached $67.3 million by the end of 2011, the company said in a regulatory filing. The value of the contract was $27.8 million.
BrightSource is now focusing on a bigger project that will generate solar electricity in the desert near Las Vegas that is a third completed. The company expects to finish the project in 2013. BrightSource more recently made headlines for withdrawing its IPO plan.
A bright view
An elevator ride to the top of the tower gives us a breathtaking view of the solar field and, beyond that, the vast scrubbed land dotted with pumpjacks, the rocking horse-like structures that pump oil out of each well. Regardless of whether the project will work out as planned over the coming decades, the gleaming solar mirror field and tower are impressive and worth a stop if you pass through the area. Its construction certainly has drawn many curious residents nearby.
“We did a lot to make sure they know this is not an Area 51 thing,” says Morgan Crinklaw, a Chevron spokesman who accompanies us on the tour. “People would drive out here, tailgate, drink beer and watch this.”