Southern California Gas Co. hired the Scripps Institution of Oceanography to find a way to capture the carbon dioxide from gas combustion and use it to feed algae, which could then produce other products, the institution and the utility said Monday.
Natural gas combustion produces less carbon dioxide, and therefore contributes less to global warming than oil and coal, but it still has a carbon footprint, said a SoCal Gas executive. Under a two-year, $500,000 contract, Scripps will design a system to take carbon dioxide from a natural gas-burning power plant or factory and shunt it into a pond for algae production. The algae itself could then produce several other useful products, or become an animal feed itself.
"What we want to study is how much CO2 could we capture from a power plant and turn it into algal biomass," said Dominick Mendola, one of the two lead researchers at Scripps.
Under the contract, Mendola and his co-lead researcher, Greg Mitchell, will review the literature on carbon capture and algae growing, and visit places where carbon capture is already under way. They will then design a demonstration project for SoCal Gas. The utility will issue a new agreement before it goes forward with a demonstration project.
The project could be one of the keys for SoCal Gas, the largest natural gas utility in America, and its sister company, San Diego Gas & Electric Co., in meeting California's anti-greenhouse gas regulations.
"We're among those that have a real stake in this being successful," said Jeff Reed, director of emerging technologies for SoCal Gas.
Reed's hope is that the system Mendola and Mitchell will design can be a "100 percent closed carbon system." Though 100 percent may be a bit optimistic, given the likelihood of leaks, it certainly could contain a great deal of the carbon dioxide that comes with natural gas combustion.
Broadly speaking, one such system would take carbon dioxide from a power plant and bubble it into a pond where algae was growing. Like all plants, algae uses carbon dioxide, water, sunlight, and other nutrients to grow.
The algae could be used as animal feed ---- Mendola said algae is very high protein ---- but it could also be used to produce more natural gas. Thanks to years of research, scientists havegenetically modified algae to produce a variety of products, including feedstock for plastic, oil, or pharmaceuticals, and more methane. That methane could be cleaned and pumped back into the pipeline, creating a closed system.
"We think it's very interesting for the dual potential benefits in the carbon capture and the energy (and) feedstock arena," Reed said.
San Diego has long been a center for algae and biofuel research. In addition to the Scripps Institution of Oceanography, the region hosts the Scripps Research Institute, Sapphire Energy andSynthetic Genomics Inc., all of whom have major algae biofuel operations.
But while scientists have succeeded in producing these useful bioproducts on a small scale, large-scale algae production remains elusive. Algae needs large quantities of water to grow, exposure to sunlight, and plenty of land. The growth ponds can easily become contaminated by other species of algae and other microbes, and they can require a lot of land.
Reed recognized these challenges, but he believes those technical problems can be overcome.
"We're very excited at The Gas Company for renewable methane," he said.