The Coalinga oil field in California has been pumping out crude since 1887, and the remaining oil has gotten heavier and heavier and harder and harder to extract—but it will soon get a boost from the sun. Specifically, the old field will use steam generated by concentrated sunlight to help melt the remaining heavy oils and make them liquid enough to be pumped to the surface.

"It's operating and providing the bulk of the steam generated to support enhanced oil recovery," explains Jerry Lomax, vice president of emerging energy at Chevron, the energy company that funded the project. The idea is to "turn photons into solar steam and then… get that into an oil field injector."

Chevron partnered with BrightSource Energy, a company that designs and builds concentrating solar power plants, to build a version of that technology in the Coalinga oil field. They have built more than 7,000 mirrors on mechanized devices—known as heliostats—to track the sun on 65 acres and concentrate sunlight from this broad area to a point atop a 327-foot-tall tower. Inside that tower, water turns to steam at a pressure of 700 pounds per square inch and an average temperature of 500 degrees Fahrenheit. That steam flows to a heat exchanger, where it turns water from the oil field to steam so that it can be pumped back underground to loosen the remaining oil. All told, the power tower system pumps out 350 barrels of steam an hour, which will be used to supplement water boiled to steam by burning natural gas if testing goes well.

"It's an extra 5 percent for them," Lomax says, "and they save that much natural gas." As it stands, Chevron pumps nearly 8,000 barrels of "oil equivalent" per day out of the Coalinga field.

Over the course of 2012, Chevron will determine how reliable the solar steam is, as well as what kind of steam volumes it can expect under various conditions. By next year, once hookups are in place, the solar steam will start supplementing that from burning natural gas. "Solar steam will always be an augmentation of an alternate traditional fuel source, such as natural gas, so we have 24-hour coverage," Lomax says. On the sunniest days, the system can produce steam almost 12 hours of the day, but Chevron will investigate whether it is feasible to run an oil field exclusively on solar steam as part of this demonstration project.

Heavy oils are a big part of new oil being produced around the world, whether oil from the tar sands of Canada or thicker crude from Indonesia. Chevron has brought up 150,000 barrels of heavy oil in California alone and roughly 500,000 barrels per day around the world. Solar steam—should it prove successful in California's San Joaquin Valley—might make sense to get more oil out of the ground in places like the partition zone between Saudi Arabia and Kuwait or Indonesia. "All three locations have sites with ample sunlight and ample amounts of flat acreage near oil fields where you could include a solar field of this scale," Lomax says, and the company is also studying whether solar steam might make sense for complexes that refine oil or produce petrochemicals, both of which employ a lot of heat.

Of course, oil fields are not the friendliest or cleanest places for mirrors that must remain highly polished to be effective. Thus far, the oil company has only broken one of the heliostats by running into it with machinery and has been pitting human crews against automated cleaning machines. "The machine uses slightly less water than a manual crew," Lomax says.

10 Comments

1. 1. sethdiyal 12:11 PM 4/9/12

   Another Big Oil infomercial copied done by Big Oil's favorite stenographer at SCIAM.
   
   Obviously the oil is going to burned anyway so whats the point using solar at ten times the cost of gas to heat water?
   
   Answer - propaganda in the Big Oil's media outlets painting atmospheric ogre Chevron as being so sweet and environmental benign.

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2. 2. Ralf123 01:41 PM 4/9/12

   Yay, now we can convert even solar energy into CO2!
   I keep having this feeling that 4-6C of warming by the end of the century is lowballed.

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3. 3. Carlyle 04:26 PM 4/9/12

   One day there will be small nuclear power plants, possibly even portable, that will utilize the waste heat from power generation to liquefy heavy oil & tar sands much more cleanly & economically than present methods.

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4. 4. Ralf123 in reply to Carlyle 05:45 PM 4/9/12

   Great, we can even get CO2 from nuclear energy!

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5. 5. Carlyle in reply to Ralf123 06:09 PM 4/9/12

   The world needs all the fertiliser it can get:)
   Using nuclear power for these processes cuts Co2 but do not let that clear your view.

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6. 6. Ralf123 in reply to Carlyle 07:03 PM 4/9/12

   Using tar sands and shale oil will not be sustainable. It is way too costly, from any angle that you use - dollars, EROEI, raw energy input, water use, CO2 emission etc.
   Betting on it is stupid.

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7. 7. RCWhitmyer 09:59 PM 4/9/12

   SciAm does not censor the news, and lets you choose what's bogus and what is not.

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8. 8. JamesDavis 07:22 AM 4/10/12

   Sounds like the oil companies are getting desperate and oil is getting down to its last drop; they are sucking the old cow dry. It is pretty bad when they have to stoop so low that they make themselves an oxymoron. Or maybe I should take the oxy part off of moron.

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9. 9. DaniEder 07:59 PM 4/10/12

   @JamesDavis - perhaps you missed the part of the article which said the Coalinga field is 125 years old. It's taken quite a long time to get to the last hard to get oil. Most of the world has much younger fields, so they are not yet at the heavy residual oil point.
   
   Using solar like they are doing here will just extend the life of the fields a bit more, and give us more time to make the transition to other energy sources.

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10. 10. Postman1 in reply to RCWhitmyer 10:28 PM 4/10/12

    Now that was funny! You were being sarcastic, weren't you?
    

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