Hybrid solar system boosts natural gas powerplant efficiency by 20 percent


April 17, 2013

Close-up look of PNNL’s concentrating solar power system

Close-up look of PNNL’s concentrating solar power system

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Solar power holds the promise of clean, limitless energy, but it currently suffers from high costs and an inherent disadvantage of not working when the sun isn't shining. The Department of Energy's Pacific Northwest National Laboratory is taking a best-of-both-worlds approach by developing a hybrid solar/gas system that increases the efficiency and reduces the carbon footprint of natural gas power plants.

The PNNL system uses a parabolic mirror to focus sunlight on a four by two-foot (1.2 x 0.6-m) chemical reactor lined with narrow channels 8.1 mm (0.318 in) wide. The sunlight heats natural gas in the channels next to a catalyst that breaks down the gas molecules into a mixture of hydrogen and carbon dioxide called synthesis gas or syngas. Connected to the reactor is a heat exchanger that collects waste heat from the reaction and recycles it back to the reactor to boost the process until 60 percent of the sunlight is converted to chemical energy. Tests indicate that the system allows a natural gas plant to operate at about 20 percent greater efficiency.

"Our system will enable power plants to use less natural gas to produce the same amount of electricity they already make," says PNNL engineer Bob Wegeng, who is leading the project. "At the same time, the system lowers a power plant's greenhouse gas emissions at a cost that's competitive with traditional fossil fuel power."

It's no surprise that the system works best in areas with lots of sunshine and according to PNNL, it's adaptable to different sizes of natural gas power plant sizes with a 500 MW plant needing about 3,000 solar dishes. In addition, the syngas can also be used to produce synthetic fuels for vehicles.

PNNL plans to test the system at its campus in Richland, Washington as part of a program to increase the system’s efficiency and bring down the cost to a projected six US cents per kilowatt-hour by 2020 to make it competitive with conventional fossil-fuel plants. Also, methods aimed at mass producing the system will be developed at the Microproducts Breakthrough Institute, a research and development facility in Corvallis, Oregon, while industrial partner SolarThermoChemical LLC plans to manufacture and sell the system after development.

Source: PNNL

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

I seem to be missing something how does using a solar and catalyst to burn the carbon out of the methane without applying the chemical energy to generate heat to convert to mechanical energy to convert to electricity. Is it just a better way to generate hydrogen for a fuel cell? I think using catalytic burners and Stirling Cycle engines would use the methane more efficiently.


I wonder who pays for the 3,000 solar dishes. No I don't. While we tilt at windmills (sorry) France leads the world in cheap clean electricity production at under a nickel (Euro) per Kwh. They generate so much electricity that they don't use it all and make $3 Billion a year selling it to other countries. And, (drum roll) they use American technology to do it. We are stupid to re-elect politicians who continue to make us pay high prices for energy while they waste our money buying votes to keep themselves in office. More ethanol please!


Uh now there's a real fact checker. France "leads" and has "cheap clean" What a pile. Go to France and check how the discussion about the fuel cycle with reprocessing and plutonium and also waste management is going. Don't wanna know about problems our kids will have? Oh. I see.

And while you are "real" at it, go and check the Department of Homeland Security's pile of white papers on unintended uses of nuclear fuel cycle byproducts by people with bad intentions. You probably don't wanna hear it.

More ethanol? You never heard of any problems in the global food supply caused by us burning what could be food in our over-sized fatcars? I guess not.

The unpleasant truth about energy is that if we want to use lots, we should at least have the decency to come up with a real smart way of supplying ourselves with that energy, without doing it at someone elses expense.

There are ways. There's plenty of energy, everywhere. We just have to figure out how to use it. Stop being so pathetically scared, please. Parroting what you are told on Fox News ain't gonna help.


Actually, Im optimistic on this one...if you can take solar energy to eventually run vehicles, thats a win. How ironic (short-sighted?) it is that America uses a combustible fossil fuel like natural gas to make electricity instead of powering vehicles. Stragtegically, natural gas and oil (gasoline/diesel) should power vehicles while nuclear and coal should be used to generate electricicity.

James Barbour

realfactchecker You better check your facts, France is now considering phasing out nuclear and racing Germany toward a future powered by Solar (of all flavors)...

Also France imported German solar generated energy last year during periods when the temperature got really cold which affected the water supplies to the nuclear power plants in France!


Storing nuclear "waste" is just stupid. The high energy stuff is fuel, the gamma emitters is fuel (wrap it in tungsten and power Stirling engines.) subject the remaining material to neutron bombardment until all you have left is short half-life decay to stable like tritium or iodine 131. It is the "Greens" that make nuclear energy unsafe.


Spent nuclear fuel should be reprocessed. Its not waste its a valuable asset. That said Carter made it all but impossible to reprocess the fuel and Clinton destroyed our entire faster breeder reactor program that was a decade ahead of everyone else. Faster breeder reactors seem to be the best source of energy. The liquid sodium reactors that clinton destroyed were incredibly safe.

Michael Mantion

This seems profoundly stupid. If you already have solar concentrators and gas, why waste the gas burning it all the time instead of using basic solar thermal with gas as backup when it's cloudy?

Joe Acerbic

"... an inherent disadvantage of not working when the sun isn't shining..."

Geez. What century are you living in? Some old ethnic joke?

Free yourself from your planetary-centric world-view!

The Sun ALWAYS shines!!

If you leave the planetary surface, you can collect solar power 100% of the time, and with much better efficiency.

We've known how to do this, how to transmit it to the surface of the Earth, and how to do it economically for over 35 years!

Charles Barnard

re; Charles Barnard

Have you looked at the cost of putting stuff into orbit? $1000 per pound is a bargain.


I'm sorry but "At the same time, the system lowers a power plant's greenhouse gas emissions at a cost that's competitive with traditional fossil fuel power." is a claim based on location and not worth a jot in the world environment context.

All thats happening is the methane and CO2 fraction is being stripped back to hydrogen and CO, which is then burned as fuel.

The only 'environmental' difference is less CO2 is released at the plant, and the gross is now released at the generator.

"Geographing" emissions might fool idiots, journalists, investors and politicians; but it won't fool the laws of thermodynamics or the biosphere.

Drake Kyzine

Uhm, Guys?

Syngas is a single step away from being Methanol, via the Fischer-Tropsch Process.

A Cobalt catalyst, a pressure vessel, and you've got Methanol you can run your car on, from Natural Gas.

Hmm. That changes the picture a bit, doesn't it?

William Carr
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