Chevron Makes Use Of Solar Energy to Recover Oil

When you think of solar energy, it's likely that you imagine a clean and renewable power source; something that goes towards getting us off our global dependence on fossil fuels. And while it probably won't be a technology that gets us away from CO2 emissions altogether, every watt of solar energy produced is watt of energy that doesn't incur greenhouse-gasses.

So, what if solar energy is generated in order to extract oil from mature oil fields? Does this constitute a spectacular irony, or a clever application of renewable energy; one that may be justified in a world where oil is likely to remain fundamental to our economy for a considerable number of years to come?

As far as Chevron is concerned, it's a smart use of renewable energy, and to demonstrate this, they have just launched the world's largest solar-enhanced-oil-recovery project in Coalinga, California.

The Easy Oil Has Been Taken

The history of Coalinga in Fresno County, California, is quite interesting and effectively illustrates the life-cycle of an oil well. Firstly, were it not for fossil-fuels, the town wouldn't exist. It was originally called "Coaling Station A," dating from a time when coal mining was the main reason for its being, and where the Southern Pacific Railroad set up a station for coal distribution. The name Coalinga is simply a composite of "Coaling" and "A" - and the subsequent discovery of oil in the mid 1800's has supported a relatively prosperous community for well over 100 years.

In the early 1900's, oil fields in Coalinga often produced "gushers," oil wells that rage out of control, sending columns of oil into the sky. Coalinga's so called "Silvertip gusher" was the largest, and in 1909, it pushed out ten to twenty thousand barrels of oil a day - under its own pressure.

Peak production in the town occurred in 1912 - but 100 years on, the easy oil is gone, so now, you have to apply energy to extract what's left. Since the area produces heavy-crude, steam is injected into the ground to heat the oil deposits; the heat reduces oil viscosity allowing it to be extracted.  But putting energy into the ground to get energy out of ground is a fine balance, and most likely, this is why Chevron came to develop the solar solution - to keep aging wells economically viable for longer.

Solar Replaces Natural Gas

The process of injecting steam for oil recovery is not new (and to be clear, should not be confused with hydraulic fracturing). But up to now, the industry has typically used natural gas-powered generators to produce it. Chevron's solar solution replaces natural gas generators, thereby making it a clean-energy replacement for steam production.

While the Coalinga project will be run by Chevron Technology Ventures,  the system itself was developed by BrightSource Energy inc. It utilizes "concentrating solar-thermal power" (CSP) technology, which involves using numerous mirrors to concentrate sunlight onto a solar tower to produce steam.

In CSP electricity generation,  steam drives a turbine, whereas in this application, since electricity is not the desired product, the steam is injected directly into the ground to free up oil. The Coalinga site covers 100 acres and uses 7,600 10 feet by 7 feet mirrors, which track the sun on 6-feet tall poles. The mirrors focus sunlight onto a 327 feet tall solar steam generator - and natural gas, which would normally be used in the steam production process, is displaced.

Whatever you think about the sensibilities of using solar energy to get at fossil fuels, it's worth putting this development into context. The San Francisco Chronicle, reporting on this story, highlighted that 32 percent of California's industrial and commercial gas use is currently used for enhanced oil recovery - and in years to come, 60 percent of California's oil production will use enhanced recovery methods. So, if solar steam-generation can be scaled, there is the potential to save a tremendous amount of natural gas. Furthermore, the Chronicle reports it's already cheaper to use solar energy than natural gas for this application.

BrightSource says the global enhanced-oil-recovery industry could be worth around $16.3 billion by 2014, and their solar solution could be used in regions where natural gas is expensive, unavailable or both. Essentially, this technology could become an important way to improve access to harder-to-get-at oil.

Solar As Enabler Of Oil Dependence ?

Which begs the question: Does this development mean the solar industry might become an enabler in extending the world's addiction to oil? or does it merely offer a pragmatic (and at least cleaner) way to address the world's growing hunger for energy - in which oil is doubtless going to remain a part? Maybe it's both.

But it does bring up the question of peak-oil too, which as this New York Times piece from 2007 suggests, is not a fixed point in time. A Chevron engineer quoted in the NYT piece said, "..peak oil is a moving target....Oil is always a function of price and technology." Could this new use for cheaper solar technology shift out the point of peak-oil further still? If so, readers will decide whether that's a good, or a bad thing.

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