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Potential For Solar-Assisted EOR in California Oilfield Still Unfulfilled

A four-year project at a Chevron Corp. enhanced oil recovery (EOR) wellsite in California's central valley has come and gone with no plans to replicate it. Solar, in theory, could replace a lot of natural gas.

An examination of what happened with the solar EOR experiment takes on new interest as California lawmakers this month debate the details of a comprehensive energy bill (SB 350) designed to support Gov. Jerry Brown's climate change response (see Daily GPIApril 30) including cutting the use of petroleum products in transportation in half by 2030 as the industry grapples with calls for it to radically reduce greenhouse gas (GHG) emissions.

For now, a Chevron spokesperson said the solar EOR test was the company's only solar oilfield project, and there are none in the planning stages currently. Energy industry representatives closely following the negotiations on SB 350 told NGI that if the measure is passed, there could be renewed interest in solar and other alternative energy applications in the EOR sector.

Six years ago, Chevron Technology Ventures and Oakland, CA-based solar developer BrightSource Energy partnered on a demonstration project for solar thermal technology in a California oilfield to produce steam used in EOR (see Daily GPIAug. 26, 2009). It started in 2011 and operated through last year.

Chevron, which at the time was an investor in BrightSource, began the pilot program applying its "power tower" technology that deploys thousands of small mirrors called heliostats to reflect sunlight onto a boiler atop a tower to produce high-temperature steam. The steam was injected to help produce more of the traditionally thick crude oil in California's central San Joaquin Valley at a 100-acre site in the Coalinga oilfield, one of the state's oldest.

On a smaller scale, the Coalinga demonstration used the same technology as BrightSource deploys at the world's largest solar thermal project at Ivanpah in the Southern California high desert.

Former state energy official and BrightSource senior executive Joe Desmond told NGI that while the company is primarily focused on the renewable electricity and thermal storage market applications for its technology, it nevertheless "still looks for [global] opportunities to apply solar steam to other applications, such as industrial steam or EOR."

During the EOR project, solar-generated steam supplemented natural gas-fired steam generators at Coalinga, providing about 5% of the steam needed to produce the 8,700 b/d heavy crude (9-14-degree gravity), a California-based Chevron spokesperson told NGI. "As configured, the installation produced 60% quality steam at 500 degrees F and 700 psi," she said.

The solar-thermal EOR project was designed to produce 240 million pounds annually of steam, or the equivalent of 50,000 MWh annually.

While noting that Chevron does not divulge the costs of its demonstration technology projects, the spokesperson said "the economics were not attractive compared to the current [gas-fired] process," although the demonstration achieved what she called "results greater than design production goals during the first year."

Coalinga, with its 7,600 sun-tracking mirrors focusing solar power on a boiler atop a tower in the oilfield, was Chevron's only thermal solar demonstration directly supporting oil production, the energy giant's spokesperson said. For its part, BrightSource describes the four years of operation as a "successful pilot project" showing that solar thermal technology can be "used effectively" for EOR applications.

Desmond said the difference in the two companies' conclusions stems from the fact that from a potential commercialization standpoint, the demonstration didn't pencil out for Chevron's plans to replicate elsewhere, while from a research project's objectives, the test met its expectations. "It validated the technology's ability to consistently deliver the necessary steam and temperatures at or above what was expected," he said.

The relative economics of the solar EOR applications in California, however, could change based on what happens "with the state's efforts to look at decarbonizing the upstream activities connected to oil production," Desmond said, referring to SB 350 and Brown's climate change agenda.

In addition to California, EOR is burgeoning in parts of the Permian Basin and in various areas around the globe; Chevron at one time considered applying a solar-steam project in the Middle East, but so far it has not moved ahead with any project, the spokesperson said. In the oil/gas industry's push back in recent years regarding the controversial California low carbon fuel standard (LCFS), the large volumes of natural gas used to produce the oil have inflated the carbon footprint for the state's oil production under LCFS.

Some critics in the state have advocated "other forms" of EOR, and within the industry, majors like Chevron at times have pointed to the potential use of solar energy to produce the steam used in EOR rather than natural gas as a means of meaning LCFS (see Daily GPIFeb. 20, 2013).

As a comparison to the 100 acres needed for the Chevron solar EOR installation, the utility-scale power generation at BrightSource's Ivanpah site near the California-Nevada border uses more than 3,500 acres that are covered with mirrors for three power tower segments adding up to 392 MW of gross capacity. Ivanpah has more than 300,000 mirrors, compared to Coalinga's 7,600.

Longer term, EOR worldwide could be a market for solar-assisted steam generation. Projections in July by Transparency Market Research, for example, projected that a 2012 global EOR market of $38.1 billion will reach $516.7 billion by the end of 2023, and in 2012 North America dominated the global market accounting for 38.9% of the EOR sector.

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