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The Marriage of Solar Energy and Natural Gas

Solar and natural gas combined for more efficient nat gas power generationLadies and gentlemen, we are gathered here today to witness the union of two nobody ever thought would join.  By the powers vested in me, I give you: Solar Energy and Natural Gas.

The Department of Energy’s Pacific Northwest National Laboratory has developed a method of combining solar energy into the natural gas production process to produce cleaner energy output with the same fossil fuel input.  Put simply, natural gas power plants will soon be able to produce more electricity while using the same amount of natural gas.

What’s more, the process reduces greenhouse gas emissions from natural gas power plants at a cost that is competitive with traditional fossil fuels, creating a win-win-win scenario.

Natural gas is the next oil or gold rush. As production skyrockets, Americans are demanding natural gas as a cheap, slightly cleaner alternative to other energy sources.  As demand rises, natural gas power plants are being constructed at an alarming rate to take advantage of low cost fuels.  With this new method, scientists have sweetened the taste of natural gas even further.

The product, dubbed “syngas” for synthesis gas, consists of hydrogen, carbon monoxide and at times carbon dioxide.  Concentrated solar energy is used to add heat to the thermo-chemical process that yields partially synthetic natural gas.  Although still containing harmful atmospheric contaminants that contribute to global warming, this process makes the overall production of natural gas more efficient without contributing to the carbon footprint.

“About four feet long and two feet wide, the device contains a chemical reactor and several heat exchangers. The reactor has narrow channels that are as wide as six dimes stacked on top of each other. Concentrated sunlight heats up the natural gas flowing through the reactor’s channels, which hold a catalyst that helps turn natural gas into syngas.”

The solar technology used in this application is not new. The system uses parabolic mirrors to concentrate the sun’s thermal energy onto a catalyst that transfers heat into the power plant.  A power plant in the pacific northwest will begin testing the technology this summer with expected promising results.

Power plants that use this technology could be considered hybrid fuel power plants, opening a door to a whole new type of energy generation. Who knows, as technology evolves, solar energy could make up a more significant portion of the energy (and non-existent emissions) of electricity generated from natural gas.

Cyrus Patten is a human services administrator and consultant in Burlington, Vermont.

Image credit Pacific Northwest National Laboratory, courtesy flickr

The post The marriage of Solar and Natural Gas appeared first on Global Warming is Real.

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Rick Engebretson's picture
Rick Engebretson on April 18, 2013

High temperature chemistry is as old as making pottery. It is worth wondering how different history might be if low cost reflective surfaces had been available as they are now.

Small scale, modular systems have transformed the physics of consumer electronics. Perhaps chemical engineers should spend less time scoffing and more time competing before they become yet another forgotten footnote.

Bob Meinetz's picture
Bob Meinetz on April 18, 2013

This 2011 study, financed by Infinia Corp. (a solar contractor) describes a process that increases natural gas production by 20% – when the sun is shining. In the sunny American Southwest that translates to about 20% of its rated capacity, meaning this development shows the potential of a 4% increase in energy production from gas.

Battelle, which runs Pacific Northwest, boasts: “one unique feature of Battelle’s contract with DOE allows research to be conducted for private industry”. Another example of why when it comes to research, government and private industry mix about as well as, er, oil and water.

John Miller's picture
John Miller on April 18, 2013

If the solar-thermal process produces hydrogen, carbon monoxide and some carbon dioxide it appears to be a novel variation of an existing commercial process commonly used to produce hydrogen from natural gas; methane steam reforming.  The net energy of the syngas fuel is increased slightly by the energy supplied from the solar concentration mirrors, which directionally increases the combustion energy value of the syngas fuel as envisioned.  The major challenge will be costs.  This syngas fuel will probably be very expensive based on a fully amortized cost of the solar-catalytic reactor/production equipment (or the $/Btu of syngas vs. natural gas).  

Schalk Cloete's picture
Schalk Cloete on April 18, 2013

I also wonder whether the 25% increase in the heating value of the syngas product over the methane feedstock will be worth the substantial increase in process complexity. The process might be useful if the syngas is further shifted to pure hydrogen and CO2 is captured from the fairly concetrated product stream. New hydrogen turbines and fuel cells could make significant contributions to high efficiency and clean power production and transportation if abundant clean hydrogen can be made available. 

Otherwise it could be better to simply use the solar concentrator plant to supply some low-grade heat to the air stream entering the combined power cycle. The highly concentrated energy in natural gas can then be used more economically to further heat the gas to the temperatures required by the high-efficiency gas turbine. 

John Miller's picture
John Miller on April 18, 2013

Schalk, fully converting methane to hydrogen and recovering the carbon dioxide is exactly what some current commercial processes do for producing hydrogen used in the Refining and Petrochemical Industries.  Most methane reformers with ‘shift reactors’ (converts residual carbon monoxide to hydrogen and carbon dioxide) vent the carbon dioxide to the atmosphere.  I once managed such a plant where we installed process equipment to recover-purify-liquefy the carbon dioxide for sales to the Food and Chemical Industries.  The problem statement is still the same, methane steam reforming hydrogen probably costs 3+ times natural gas based on the heating value cost; $’s per million Btu’s (based on my past experience).  The same issue is true regardless whether it’s burned (ICE or gas turbine) or used for fueling a hydrogen fuel cell.

Unless some major breakthrough is made in the efficiency of converting methane to syngas or hydrogen, it’s probably much more economic to invest in solar PV and use the natural gas to fuel CCGT’s or use it as a basic heating fuel.

Rick Engebretson's picture
Rick Engebretson on April 18, 2013

The process could also be a proof of concept using methane as a model feedstock molecule to manufacture reagents suitable for consumer liquid fuels. The stated product profile looks like a carbohydrate (like cellulose) feedstock, not like natural gas (methane) that should have no oxygen.

In about 1990 this group at PNW was very nice and provided quite a large packet of printed designs showing efforts to convert Municipal Solid Waste into fuels. The chemistry then required large amounts of fuel for process energy, so there was little energy gain; just eliminate garbage. This now has shown that solar energy can be used in process chemistry, with a net gain in product energy and broad product utility.

Solar fuels has become part of the RE lexicon.

Schalk Cloete's picture
Schalk Cloete on April 19, 2013

Thanks John. Wow, I sometimes wish I already had such valuable practical experience myself. If possible, could you estimate from the top of your head the cost contributions of the reforming, the WGS and the H2 purification steps? Also, how much of the 3+ times price increase is caused by the enegy input in the reforming step?

We are about to start a new lab-scale project on a reactor concept which uses the principle of chemical looping reforming with integrated hydrogen membranes for cost-effective hydrogen generation with integrated CO2 capture. The reactor will basically combine the reforming, WGS and H2 purification steps all in one while requiring a relatively small reactor volume and relatively low temperatures due to the good mass transfer in the fluidized bed reactor. If the concept works, we will do some economic assessments and it would therefore be nice to know where the greatest potential for cost reduction lies.  

John Miller's picture
John Miller on April 19, 2013

Schalk, as I recall the methane steam reforming step consumes over half the total energy (tubular reactor direct radiant fired heat).  The fired heat is required for the endothermic reaction-high temperature severity of the catalytic reactor (1000oF+).  The WGS reactor uses the least amount of energy (about 10%).  The balance of the energy is due to the utilities required by the overall process: hydrogen product compressor, steam generation for the co-feedstock mixed with the methane feed, boiler makeup water for the cooling of the reforming reactor effluent, the hydrogen purification absorbent stripping steam and cooling costs (modern hydrogen generation plants use membrane systems today), and the utilities to pump the boiler makeup, cooling water, CO2 absorbent, waste water, etc.

If you want to discuss further, I suggest you contact me directly through theenergycollective messages. 

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