The peak of oil is coming fast, says all experience. Worldwide discoveries fell off a cliff in 1985 and have been well below consumption ever since. Both British and Norwegian production in the North Sea has peaked. Mexico's Cantarell field has peaked. Even Kuwait's biggest field has peaked. Saudi Arabia's Ghawar field, biggest in the world, is rumored to be pumping 80% water and can't be far behind. What's going to happen?
The executives of oil companies and rulers of the oil oligarchies may have very narrow expertise and large blind spots, but they are not stupid. They know their own business very well. We can expect them to take actions which increase their return on investment and keep them relevant for as long as they can.
Saudi Arabia is a big case in point. It produces about half its output from just one oil field. Its remaining fields are either small, yield heavy/sour oil, or both. These heavy-oil fields include Safaniya. The lack of demand for this heavy oil (which is not easily processed in conventional facilities) has caused the Saudis to look at refining it themselves and selling product instead of crude.
This would be a very profitable move, but also more than that. It would allow the Saudis to extract billions more barrels of oil from their light/sweet fields like Ghawar.
One of the problems with the refining of heavy, sour oil is that it is involved and expensive. I gather that the coking, hydrocracking, hydrodesulfurization and other processes expend a considerable amount of the crude. Perhaps the best method is to gasify the oil, scrub it of contaminants, and synthesize only the desired hydrocarbons via Fischer-Tropsch or other processes. The resulting fuels can be made to order: ultra-low sulfur, low aromatics, tailored vapor pressure, high octane/cetane, even synthetic methanol and ethanol. These would command top dollar.
Both hydrogen production (for cracking and desulfurization) and gasification processes convert part of the input into carbon dioxide, which is not a feedstock for fuels and must be removed. Other processes also generate carbon dioxide; all the gas-fired desalination plants, powerplants and future gas-to-liquids plants will make plenty. In most of the world this is just a waste product, but in Saudi Arabia, carbon dioxide would be a valuable substance. The injection of water to maintain pressure is a danger to the oil fields; water isolates the immiscible oil in pores in the rock and prevents it from flowing to the wells. But what if the injected liquid wasn't an immiscible fluid, but a solvent?
Supercritical carbon dioxide is a solvent for many things; it is being used as a clean replacement for chlorinated dry-cleaning fluids. It also mixes with at least some types of crude oil and makes them more fluid. CO2 from a synfuels plant in N. Dakota is being piped to an oil field in Weyburn, SK. The injection of carbon dioxide has already raised the production of the field to more than 2/3 of its former peak (production graph), and is projected to greatly increase its ultimate recovery. Applying the same techniques to a field like Ghawar could increase its total production by tens of billions of barrels. At future prices, that could amount to trillions (that's trillion with a T, 1012) of dollars of product.
The same techniques could be applied to old fields in the USA; Pennsylvania and the band from Texas through Kansas have plenty of oil in the ground that's unrecoverable with previous techniques. Pumping captured CO2 (available from any coal-fired powerplant converted to IGCC, and there are plenty of powerplants in Ohio) into the ground could bring up a lot of that, and both cut net carbon emissions and soften the production declines that are coming. Unfortunately, I don't see this happening here. The vision doesn't exist; the electric utilities aren't interested in oil and will stonewall anything that looks like carbon emission limits, the oil companies see no money in reviving fields they no longer own and may already have paid to cap, and there's nobody like a T. Boone Pickens ready to put them together for his own profit.
In the end, the most effective palliative to oil depletion may wind up disused except by accident; the Weyburn Option may mostly be exercised by one of the least sophisticated and innovative societies on earth. The trillions they reap from it will not be used to push us forward, but to bring the whole world back to the 7th century AD.
I'm normally an optimist, but that's one all-too-likely future that seems mighty ugly.
The USA generates about 20% of its electricity from natural gas; 699.6 billion kWh [1] were produced from gas in 2004. This consumed 6,020,335 million ft^3 of gas [2] (roughly 6.2 quads) of our total consumption. The net efficiency was roughly 39%; the other 61% of the energy turned into heat. Only 31% of this gas-fired generation was in combined heat and power plants; the heat from the other 69% was discarded.
The 60.5 million households using natural gas for heating in 2001 used a total of 3.32 quadrillion BTU of gas for heating [3], or roughly 55 million BTU each. The 8.5 million households heating with fuel oil [3] used 0.58 quads, or 68 million BTU each. The 6.6 million households heating with LPG used 0.28 quads, or 42 million BTU each. Together, these 75.6 million households used a total of 4.18 quads of heating fuel in 2001, averaging 55 million BTU each.
Commercial buildings are similar. In 1999, commercial space used 1.76 quads of natural gas and .17 quads of fuel oil [4] for heating. Together, the fuel used for heating residential and commercial real estate came to 6.1 quads. This is nearly the same amount of energy as all the natural gas used for electric generation, and most of it is consumed during the half-year of the heating season.
Home-heating oil is almost the same as diesel fuel, and both LPG and natural gas are high-octane motor fuels; every home and business which has heating fuel delivered in tanks or pipes could run a generator to provide its electricity too. The generator converts part of the fuel's energy to electricity and the rest to heat. Creating the heat where heat is needed is better than making it where it has to be discarded.
Cogenerating electricity with heat creates large efficiencies and could have eliminated the prospect of a natural gas shortage this winter... if we had done it. How much? Here's an example:
Suppose the typical house uses 55 million BTU of gas for space heat over the heating season (average 367,000 BTU/day over 150 days) and consumes 15 kWh/day of electricity over the same interval (2250 kWh total). If the electricity was generated in a 39%-efficient gas-fired plant, it would require 19.7 million BTU of gas. The total for heat and electricity would be 74.7 million BTU of gas. If 63 million BTU of gas was burned in a generator at 12.2% electric efficiency and 95% overall efficiency, it would make 7.68 million BTU of electricity (2250 kWh) and 52.2 million BTU of space heat (what a 95%-efficient furnace would deliver from 55 million BTU of gas). This would both heat and power the house on about 15% less fuel. This could easily make the difference between a crisis and a yawn.
12.2% is a rather low efficiency for a generator; small diesel engines can reach 30% without undue difficulty. Suppose that the houses heated by natural gas and LPG use generators getting 25% electric efficiency (95% overall), and the ones heating with oil get 28%/95% out of theirs. These houses would burn some extra fuel but generate large excesses of electricity. This electricity could run electric vehicles (displacing motor fuel and making it available for home-heating oil), heat pumps (cutting total fuel demand further), or go for other purposes.
A cogenerator running at 30% electric efficiency and 95% overall efficiency would burn about 46% more fuel than a furnace for the same amount of heat, but it would have an electric output of 46% of its heat output. If this electricity ran a heat pump with a typical 3:1 coefficient of performance (3 BTU of heat out for each BTU of electricity in), the total heat available from the fuel would be 238% as much as the original demand (100% from the cogenerator and 138% from the heat pump). The net heating efficiency would be 155% (65% cogenerator, 30%*3 = 90% heat pump), squeezing 63% more heat out of each unit of fuel. Again, this is enough to turn a fuel crisis into a yawn.
It's gotten warm in Michigan this past week, but people are either looking at their heating bills from the previous cold snap or are waiting in uneasy anticipation thereof. The US chemical and fertilizer industries are dying because of sky-high natural gas prices. Cogeneration could have made things a lot better. Our current situation is entirely due to our own refusal to be ready for the future that's coming at us - ready or not.
Footnotes:
[1] http://www.eia.doe.gov/emeu/aer/txt/ptb0802a.html
[2] http://www.eia.doe.gov/emeu/aer/txt/ptb0805a.html
[3] ftp://ftp.eia.doe.gov/pub/consumption/residential/2001ce_tables/enduse_consump2001.pdf
[4] http://www.eia.doe.gov/emeu/cbecs/text/c1.txt
The nitwits at Blogger have decided to stick word verification on the post-creation page.
I've complained to tech support, but it hasn't gone away. Worse, the Captcha image isn't reliably updated, so I get harassed for entering the "wrong" text.
I've been a Blogger user for almost two years, but they keep finding new ways to alienate me. If they are trying to drive users away from their service, gratuitous nuisances like this are a good way to do it.
How is that wrong? Let me count the ways:The way I understand it, it is impossible to argue against global warming per se. The world is getting warmer, and that is provable. Just as the world got colder for the Little Ice Age.
The pseudoscience comes in with discussions about *why* the world is getting warmer, and what will happen in a warmer world, and what we should do about it. That's where you see most of the handwaving and the fudging the numbers.
Let's see. Temperatures have been on the rise since the early 1900s, but greenhouse gases have been on the rise since the 1950s or so. Hmm. Is there a link?
Before we got in the habit of burning coal and oil, the atmosphere's CO2 level varied like this:
The highest pre-industrial CO2 concentration determined from ice-core data was 298.7 ppm a bit over 320,000 years ago.
Recent history is very, very different:
We're now up to ~380 ppm and rising at about 2 ppm/year (data). There is no honest way to deny this. Carbon dioxide is a major greenhouse gas and is one of the determinants of the troposphere/stratosphere boundary (which is where convective transport of heat ends and radiative transport takes over); there's no informed, principled denial of that either. The deeper the convective layer (which is too "optically deep" at IR wavelengths for heat to escape by radiation), the hotter the surface; this follows by straightforward thermodynamics. There are complications such as chaotic weather patterns, non-uniform and time-variable atmospheric and oceanic heat transport and more, but they do nothing to contradict the broader principles.
At Real Climate, there's a thread about skepticism which is very much on-point. It starts with some pertinent observations by Bertrand Russell. The money quote (all errors theirs):
There are matters about which those who have investigated them are agreed. There are other matters about which experts are not agreed. Even when experts all agree, they may well be mistaken. .... Nevertheless, the opinion of experts, when it is unanimous, must be accepted by non-experts as more likely to be right than the opposite opinion. The scepticism that I advocate amounts only to this: (1) that when the experts are agreed, the opposite opinion cannot be held to be certain; (2) that when they are not agreed, no opinion can be regarded as certain by a non-expert; and (3) that when they all hold that no sufficient grounds for a positive opinion exist, the ordinary man would do well to suspend his judgment.
The facts in this case are:
I am not a climate scientist. The soi-disant skeptics (deniers) can say anything they want to or about me, and it proves nothing; what they need to do is come up with a model that is
Discussion here is pointless; I'll be reading there.
There's an estimated 1.3 billion tons of unused (waste) biomass produced in the USA every year. <Dr. Evil voice> 1.3 billion tons. </Dr. Evil voice> Sounds like a lot, doesn't it? Should be a great energy supply, right?
Maybe, maybe not. It depends how it is used.
The buzz today is all about cellulosic ethanol. Ethanol is touted because it is miscible with gasoline and can be used by some vehicles in concentrations up to 85% (E-85). There is a large agribusiness lobby behind ethanol, which claims it as the route to energy independence. Is it?
Iogen is a biotech company which makes enzymes for the hydrolysis of cellulose to sugars; these sugars are then available for yeasts to ferment into ethanol. Iogen claims a net yield of 330 liters (87 gallons) of ethanol per dry ton of biomass. This is an energy efficiency of roughly 48%; the balance of the energy is in lignin which is not converted to sugars (and typically burned to distill the ethanol) or used by the yeast for their own metabolism.
A gallon of ethanol has energy equivalent to roughly 2/3 of a gallon of gasoline, so Iogen's process turns a ton of biomass (roughly 15.2 million BTU) to the equivalent of about 58 gallons of gasoline (about 7.3 million BTU). 1.3 billion tons of biomass would yield 75 billion gallons-equivalent, about 54% of US gasoline consumption or about 38% of total US motor fuel consumption last year. Due to other uses of petroleum, it represents an even smaller fraction of total demand.
This is clearly not going to get us to independence; even with complete use of the entire 1.3 billion tons, losing about a quarter of petroleum supply would put us right back where we are now. But are there other ways to use this biomass surplus which would get us there?
Maybe.
Someone I won't name has been bugging me to write about direct-carbon fuel cells (DCFC's). These things are lab test articles and not ready for production, but they are remarkable nevertheless. The efficiency of any energy conversion machine is limited by the increase in entropy during its operation; entropy can only be carried away as waste heat, and so limits the possible conversion of chemical energy to electricity. DCFC's convert oxygen and carbon directly to carbon dioxide, which has approximately the same entropy as the reactants. Their theoretical efficiency is accordingly very high, and researchers claim 80% at practical current densities (100 mA/cm2).
It's easier to convert biomass to carbon than to ethanol; the production of charcoal is older than recorded history. Simple processes can convert biomass to 28-30% of its dry weight of charcoal, of which perhaps 25% of the original mass is carbon. 1.3 billion tons could produce 325 million tons of carbon, plus pyrolysis products. How far could we get with that?
A mole of carbon burns to yield 93960 calories of energy; that's 7830 calories/gram, or 32.8 kJ/g. A ton of biomass at 16 GJ converted to charcoal yields about 8.2 GJ of carbon as charcoal (51%) and the balance (49%) as chemical energy and heat in the pyrolysis gases. The carbonization of 1.3 billion (metric) tons of biomass would produce 1.02e19 joules (9.7 quadrillion BTU) of energy in addition to the charcoal. This is 1.6 times as much as all the natural gas burned for electricity in 2004; if it could be converted to electricity at 45% efficiency, it would make 4.4 quads of electricity, or an average power of 145 GW. That's more than 30% of total US electric consumption in 2004. Alternative possibilities include conversion of the pyrolysis gas to syngas followed by F-T synthesis to produce liquid fuels and other products. As a SWAG, perhaps 15% of the pyrolyzed mass might be converted to hydrocarbons; that would come to 146 million tons, roughly 42 billion gallons (1 billion barrels) of liquid at the density of diesel fuel. A half-ton of hydrocarbon per capita should meet US needs for plastics and other chemicals.
1.3 billion tons of biomass converted to carbon at 25% efficiency yields 325 million tons (325 teragrams) of carbon. At 7830 calories/gram, this represents 2.54e18 calories (1.06e19 J, 10.1 quadrillion BTU) of energy. At an efficiency of 80%, DCFC's could convert this to roughly 8 quads of electricity. This is an average power of 267 GW. But what's that compared to motor fuel demand?
US gasoline consumption in 2004 was up to 139 billion gallons; at 126,000 BTU/gallon, this comes to 17.5 quads of raw energy. But gasoline vehicles are inefficient; at 16% efficiency, only 2.8 quads of this gets to the wheels. Diesel vehicles are better. The 60 billion gallons of distillate oil consumed in 2004 contained 8.7 quads at 145,000 BTU/gallon; converted to work at 35% efficiency, it would deliver 3.0 quads to the wheels. The total of 5.8 quads is about 73% of the energy available from the carbon, allowing a surplus for other uses.
The one liability is that the DCFC cycle cannot use energy from sources other than biomass; if productivity runs low, there's the potential for a crisis. This is why I still like the thermal zinc process (driven by solar or any other heat source). Its direct path is not as efficient as the DCFC system (93960 calories of carbon yields 84670 calories of zinc, which produces 52500 calories of electricity - about 56% throughput to the DCFC's 80%) but it produces more net energy (via the carbon monoxide, the output from a mole of carbon includes another 68330 calories of chemical energy), more useful byproducts, and zinc can also be regenerated using electricity from any source. Zinc also allows nearly complete carbon capture even when the energy is used in mobile applications.
So, what CAN you do with 1.3 billion tons? The answer, I think, is "enough."
Further reading: Direct Carbon Conversion Workshop presentations.
Green Car Congress has scored not one, but two big news items today. Summing up:
First in sequence, Southern California Edison has joined the plug-in hybrid development consortium; they are now alongside Pacific Gas and Electric. (I'm not Californian; does that include all the investor-owned utilities in the state yet?) The consortium, which includes battery makers and other companies, is devoted to creating vehicles which can travel their first 25-50 miles as pure electric vehicles before having to switch to conventional hybrid mode. This is predicted to produce a typical 100-200 MPG of liquid fuel, depending on the driving cycle and charging schedule. Compared to the CAFE standard of 27.5 MPG, a 150-MPG vehicle would use only 18% of the fuel.
What's odd (and remarked upon in the comments) is that this vehicle consortium does not include a single major auto manufacturer. I'll bet that there is much resistance in Detroit to having a bunch of foreigners and Californians (who no doubt seem like the same thing to crusty old Midwestern engineers) tell them what to put under the hood.
But the second item shows that the dam may be imminent danger of bursting. Honda has announced hybrid Civic price cuts and the possible withdrawal of non-hybrid Civics from some markets. With the hybrid price premium set to fall to $1700, there are fewer and fewer reasons to buy the conventional drivetrain. Eventually, Honda may no longer build them.
Getting rid of the non-hybrid Civic is a very big shift. A company which is willing to do this is probably open-minded enough to make other bold moves. Could Honda beat Toyota as the first member of the plug-in hybrid consortium and the first company to offer a plug as a factory option? I wouldn't bet against it.
With Toyota the leader in hybrid sales and set to overtake GM as the world's biggest auto manufacturer and Honda not far behind in either respect, my prediction of auto production being 90% hybrids by the year 2020 may be pessimistic. If world crude prices continue to rise at the $14/bbl/year of the last few years, any auto company which doesn't follow in a hurry is likely to dry up and blow away.
Version 1.0. Treat it like a beta, because it is. With your help, it'll grow.
Categories:
Batteries Biofuels Coal-to-liquids Cogeneration Conservation Demand-side management Energy (general) Fuel cells Vehicles Waste (utilization) Wind
This is a collection of links and other info for reference on energy matters. Sources cited in Ergosphere postings will (or ought to be) listed here. Submissions by mail, please.
(no entries yet)
Corn stover collection project
Grass biofuel pellets
PowerPoint presentation on bio-ethanol (1.3 billion tons/year of waste biomass for fuel, p. 29)
Detailed presentation on biofuels (ethanol yield figures for woody biomass in table 2-3)
General:
(tba)
Tax incentives:
Simply Insulate: Tax info made easy. Major information for existing homes, data for new homes not present (the site claims that IRS regulations are not available yet).
Tax Incentives Assistance Project: Runs the gamut from new and existing residential to business to vehicles.
Department of Energy: the horse's mouth.
University of Delaware Vehicle-to-grid page.
(no entries yet)
Direct Carbon Fuel Cells:
John Cooper presentation
DCFC workshop presentations
Zinc-air fuel cells:
(no entries yet)
Vehicle efficiency table (source)
University of Delaware Vehicle-to-grid page.
Now there is a direct biochemical link between fructose consumption and adult-onset diabetes (h/t: Futurepundit).
Fructose sweetener is largely made by a few corporate megaliths like ADM, but it would have no market if it was not for quotas on imported sugar. Cane and beet growers have long lobbied for limits on imports to keep US prices high and their operations profitable. In response, US sugar consumers (like the candy business) have been leaving. The economic cost of subsidies for uncompetitive growers and loss of jobs is now joined by the cost of damage to human health. Isn't it about time they got sued?
I'm not a fan of class-action suits, but this is a clear-cut case where a very few powerful actors have jeopardized the welfare of tens of millions of people for their own profit. The Congress will not fix this; it was bought off long ago. If any branch of government can fix this, it will be the courts.
My electricity consumption is down 9% from last year. The only thing I've changed is to replace a power-hungry CRT with a higher-resolution LCD. If I'd known 9% of my electricity was going to the tube, I would probably have replaced it sooner!
I'm also experimenting with better ways to insulate windows. I'm not completely done with the first room (still working out design details), but things look very positive. It already takes more than 12 hours for the temperature to fall from 65 to 55; doing all the windows might increase this time considerably and seriously reduce the flow of cold air off the glass. Comfort level is up with only one and a half windows covered in one room.
I'll have to compare heat demand vs. degree-days later, but this could be substantial. The materials are inexpensive, and the construction methods are very basic. What would happen if everyone cut their heat requirements by 10% or more, just because they wanted to be more comfortable and spend less?
Think globally, take care of your own business.
Both Green Car Congress and The Energy Blog appear to have lost all material newer than December 10. Other energy-related blogs may also be affected. There are no obvious notices of outages on the typepad.com web site.
More on this as it develops.
UPDATE: Six Apart confirms the outage and that this sojourn back in time is intended to be temporary.
UPDATE 2: The problem has made Slashdot.
UPDATE 3: Things appear to be more or less back to normal.
I'm more of an analyzer than a linker, but here's another one I couldn't resist. Howard Tayler (Schlock Mercenary) appears to be making a subtle reference to a certain socio-political movement. The main part of it starts here.
A number of authors over at dKos have produced an energy policy prescription for the USA. Over a series of 20 individual sections, the authors try to address the various ills which are either plaguing us now, or will shortly.
That's the good news. The bad news is that various parts of it are inaccurate and erroneous or just vague. Overall it is much more confused than it should be.
Take this phrase: "Innovation is an American birthright." What's that supposed to mean? Do the authors imply that there's some minimum standard of innovation that the public has a right to expect, along with universal health insurance? They may have been reaching for a sound-bite, but I think they fell victim to the post-modernist notion that verbiage defines reality. Words like that have no relationship to anything concrete, and don't belong in a policy analysis that's intended to gain support beyond their own set of like-minded followers.
Or this one: "Energize America will reduce imported oil and gas by 20%." What's the purpose of this: supporting the currency, reducing emissions, foreign policy goals? Why 20%? Why not 15%, or 50%? Was this number chosen based on what is feasible, or is it just marketing? Without stating what good it does and whether and how it can be accomplished, there's no reason for people to get behind it.
Or this:
If you're like me and browse the EIA website regularly, you know that only a tiny fraction of US electricity (about 3%) is generated from oil. What does electricity from renewable sources have to do with oil imports? There's no obvious connection, and the authors decline to spell one out.Energize America will provide 20% of electricity from renewable sources
America's reliance on imported oil threatens our national security and economic stability. Foreign relations, homeland security and our economy are intertwined with energy policy. America imports 60% of the oil it consumes, and U.S. demand continues to grow in the face of shrinking supply and rapidly growing global demand.
They betray an ignorance (or even denial) of economics:
The Carbon Reduction Act will formalize trading in CO2 certificates, and impose a gradually tightening regime of CO2 emissions standards.Either this regime would cover all CO2 emissions (in which case it amounts to a carbon tax, where the tax is the market price of a certificate) or it exempts some uses (and leaves loopholes for greater emissions). Worse, the whole certificate idea fails to reward early adopters; it may be possible to make reductions much earlier, but until the cap has fallen far enough to make the certificates valuable there's no financial savings. There's also market risk; if a company makes an investment based on a certain cost of certificates and the cost is much higher or lower, they could suffer losses and have to cut back operations. The "cap" mechanism does nothing to control emissions from international trading partners, so any significant expense would have the effect of driving production (and employment) overseas. All things considered, this proposal is half-baked at best and should be replaced with a worldwide uniform tax on releases of fossil or long-term fixed (e.g. old-growth forests, peat bogs) carbon.
They can't get either their facts or arithmetic right:
In truth, the US uses about 9 million barrels (~380 million gallons) of gasoline per day, or $3.8 million/day at 1¢/gallon. Even at the claimed 320 mmgd figure revenue would be about $96 million/month, not $10 million.This act implements a compounded one-cent per gallon federal gasoline tax, with the tax increasing one cent a month for 10 years....
In the first month, the tax would be only one cent, barely noticeable, but with gasoline consumption at 320 million gallons per day, that single cent would generate almost $10 million a month for energy research.
What irks me is that these errors are present in a fourth draft of this piece. Sloppiness like this should make everyone question whether the authors should be allowed near any kind of real policy-making authority. My message to the Kossacks: if you want to be taken seriously, CLEAN UP YOUR ACT!
And if you want to read it while drinking something, stretch Saran wrap over your monitor and keyboard first.
SHEC Labs (h/t: GCC) is
touting a process to convert landfill gas (mainly methane and carbon
dioxide) to hydrogen using a two-step process:
CH4 + CO2 + 65.5 kcal/mol1 | → | 2 CO + 2 H2 | (1) | |
CO + H2O(gas) | → | CO2 + H2 + 11.6 kcal/mol2 | (2) |
SHEC claims that their process increases the useful energy of the fuel by 14% (based on the lower heating value, no doubt; if it is assumed that the water's heat of evaporation can be recovered, it's about 29%). But that's not the end. Step (2) loses energy. Why not just take the process halfway?
The final conversion to hydrogen is only necessary if hydrogen is the desired product or to sequester the carbon from the process; without that, it's just throwing energy away. Keeping more energy in the product gas would be useful for stretching natural gas, getting more out of what has become a very expensive fuel. With that in mind, I propose a modified process:
Thermochemical process: | CH4 + CO2 + 65.5 kcal/mol | → | 2 CO + 2 H2 | (1) | |
50% CO flows through, | (2a) | ||||
50% process to CO2: | CO + H2O(gas) | → | CO2 + H2 + 11.6 kcal/mol | (2b) | |
Recycle CO2 to step 1, H2 to output. | (3) | ||||
Net reaction: | CH4 + H2O | → | CO + 3 H2 | (4) |
The heat of combustion of CO is 68.56 kcal/mol, while the LHV of the hydrogen is 56.93 kcal/mol. This implies that a thermochemical process can convert 185.45 kcal (LHV) of methane into 239.35 kcal of gas mixture (plus leftover solar heat and steam), an increase of 29%. If the natural gas for a generating or heating plant was processed this way, the gas demand would be reduced by up to 22.5%.
Is it worthwhile to do this? Perhaps not; the cost of the hardware might not be justified compared to getting the same amount of energy from something else. Or maybe it's justified by its versatility; the concentrating mirrors could be used with anything at the collector, including solar Stirling engines. Whichever way the conclusion goes, it's worth thinking about.
Footnotes:
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