Oil field an unexpected source for solar energy
The Belridge oil field near Bakersfield, California, is one of the largest in the country. It has been producing oil for more than a century and last year produced around 76,000 barrels a day, according to operator Aera Energy.
Now the oil field is about to become even more remarkable. Its future production will be powered partly by a massive solar-energy project to make the extraction process more environmentally friendly, according to Aera and GlassPoint Solar, the firm that will create the solar project.
The Belridge field was discovered in 1911. Oil from the field flowed out of the ground because of natural pressure in the geologic reservoirs. Later, as the pressure declined, many companies said the field was exhausted. The field gained new life in the 1960s through a process known as enhanced oil recovery. But squeezing more crude oil from the Belridge requires large amounts of steam to loosen the heavy crude, which in turn requires energy.
Traditionally, Aera used natural gas to heat water to create steam. Now Aera and GlassPoint will use a large, 850-megawatt solar thermal array to evaporate the water that's pumped into the ground to liberate more oil. The companies say this will offset 4.87 billion cubic feet of natural gas per year and avoid the emission of 376,000 tons of carbon. The water used emerges from the process of oil extraction itself and will be recycled and pumped back into the ground.
The project was made possible by the recent extension of California's cap-and-trade system for carbon-dioxide emissions to 2030, said Christina Sistrunk, chief executive of Aera Energy, a company jointly controlled by Shell and ExxonMobil.
"We need some level of what I would call regulatory and legislative stability to be able to fund projects that really need a couple of decades worth of certainty to be economic," Sistrunk said. "The extension of that program really underpinned our ability to make this long-term commitment."
The solar thermal array will capture the sun's energy using curving mirrors that are enclosed in a greenhouse, then use that energy to heat water. A smaller, 26.5megawatt solar photovoltaic installation will help power oilfield operations. The project should start operations by 2020, the participating companies said.
This is the second such megascale solar- oil project for GlassPoint, which is building the massive, 1-gigawatt Miraah project in Oman, on the tip of the Arabian Peninsula. (A gigawatt refers to the capacity to instantaneously generate 1 billion watts of electricity; a megawatt refers to the capacity to generate 1 million watts.) The Belridge project will be California's largest solar project, the company said.