The San Diego Union Tribune recently reported that an existing natural gas power plant is being enhanced using solar power, funded in part by a $10 million grant from the Department of Energy.
The idea is that mirrors would be used to concentrate the heat of the sun either on a central tower or else using a reflective parabolic trough to heat a fluid. It is hoped that adding solar capacity to existing natural gas fired plants would add 11 to 21 gigawatts of electricity to the American grid.
This particular type of solar/natural gas hybrid involved just adding solar to a conventional plant. But the New York Times recently reported on another project, being conducted in Washington State, which uses solar power to enhance the energy capacity of natural gas.
“The new system captures solar energy in a chemical form, using the sun’s heat to break open the molecules of natural gas (four hydrogen atoms and one carbon atom) and water (two hydrogen atoms and one oxygen atom) and reshuffle them into something that burns better: carbon monoxide and pure hydrogen. The result also has carbon dioxide, which is inert.
‘The mixture, called synthesis gas, is a common building block in the chemical industry, but it requires energy to make it, usually from burning natural gas. In the Pacific Northwest design, that energy comes from the sun. Sunlight falls on a mirrored dish that looks a bit like an upturned umbrella, and focuses on a spot where the umbrella handle would be. It heats water and natural gas to 700 degrees Celsius, about 1,300 degrees Fahrenheit. A catalyst breaks the molecules up and the atoms are reassembled.”
The process would have the effect of making the resulting gas burn 25 percent more efficiently than natural gas alone. It has the added virtue that it would work even at night or during cloudy days. The plant would just burn untreated natural gas.
However it is cautioned that there is some engineering work to be done before this particular solar/natural hybrid system can be made to work. It might never be cost effective in the United States, where natural has is cheap. But the technology might prove useful in other countries, such as Japan, with a shortage of fossil fuels.
In any case, as Badr Jafar, Chief Executive, Crescent Enterprises suggested recently in the Huffington Post, natural gas is likely to be the fuel of choice for many decades to come. However if solar energy can be used to enhance its efficiency, solar/natural gas hybrids would extend that period for an even longer duration.