Could Natural Gas Replace Petrolium as a Motor Fuel?
August 3rd, 2008
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The “Pickens Plan” proposes to cut US oil imports by providing alternate means of generating electricity (namely wind power) and thus reducing or eliminating the use of natural gas to generate electricity. Beyond the obvious issue with providing such an enormous amount of wind energy, as well as storage to provide reliable energy from an inherently intermittent source, it’s important to consider whether the natural gas used for power generation even could replace petroleum or at least imported petroleum. The United States currently imports more than 60% of the petroleum used domestically.
In order for it to do so, it would need to address the use of petroleum as a motor fuel, by far the largest end use and the most difficult to address by other means. While natural gas could be used in some applications it would be difficult or impossible to use it effectively in applications like aviation. It could certainly replace the use of oil for applications like heating.
But would it be enough? Lets run the numbers.
Could natural gas be used as a motor fuel?
Internal combustion engines can burn natural gas and compressed natural gas has been used as a motor fuel for some time. Gasoline engines can be modified to burn natural gas, but the range from onboard tanks of natural gas tends to be less than that from gasoline. Diesel engines cannot run on natural gas alone although they may be able to run on natural gas combined with diesel.
However, it is important to note that compressed natural gas requires different tanks than gasoline, as natural gas is not a liquid except at enormous pressure or extremely low temperatures. This presents a problem for a transition to natural gas, as cars would require two entirely separate tanks and fuel systems in order to burn both natural gas and gasoline. Bi-fuel vehicles have been produced and are used in some parts of Europe, so it is possible that this could be used as a transitional step. However, this would increase both the expense of the system and limit available storage space, as CNG tanks tend to be larger than gasoline tanks.
Beyond this, current gas stations do not provide CNG service. This results in a catch-22 for any transition. There is little incentive for gas stations to add CNG service until a large number of cars have CNG tanks yet there is little incentive to install the large and bulky tanks when gas stations do not offer CNG.
It is possible that a transition could be made through fleet vehicles, which already occasionally use CNG or through filling at the homes of vehicle owners, since natural gas service is already available to numerous residences.
On the plus side natural gas is a clean burning fuel, although the primary component of natural gas is methane, a greenhouse gas more potent than CO2 by more than twenty times. The constant transfer of natural gas to vehicles is likely to present significant opportunity for leaking, thus possibly negating any potential reduction in emissions due to the high ratio of hydrogen to carbon in natural gas.
Is there enough natural gas available from natural gas power generation?
Natural gas currently provides about 19% of the power generation in the
The following figures come from the US department of energy:
Total US Crude Oil Consumption: 20,687,000 barrels/day
Total US Crude Oil Imports: 12,390,000 barrels/day
Energy Density: 1 Barrel = 42
Total Oil Energy Equivalent: About 120 Trillion BTU/day
Or approximately 3.6 quadrillion BTU/Month
Imported Oil Energy Equivalent: About 71 Trillion BTU/day
Or approximately 2.13 quadrillion BTU/Month
Therefore, to replace the energy from imported petroleum will require 2.13 quadrillion BTU of energy per month from an alternate source, assuming that the replacement energy source can be used in engines with equal thermal efficiency. Of course, there will be some variability depending on the month and the demand at a given time.
According to the DOE, the
One cubic foot of natural gas = About 1000 BTU
Thus, the total energy from natural gas used to generate electricity in one month is about 500 trillion BTU.
Thus only about ¼ of the total
But it gets worse. Although most of the natural gas used in the United Sates is domestic, over 300,000 cubic feet of natural gas are imported monthly, although a large portion are from
Conclusion:
This the Pickens Plan is not only questionable due to the feasibility of replacing a large portion of the US power generation capacity with wind, but it also would only result in modest reduction of petroleum use and at an enormous cost, including the conversion of a large portion of vehicles in the US to use natural gas.
Furthermore, retiring natural gas power plants may not be a wise decision if alternate means of generating electricity does become available. Natural gas power plants are far less environmentally damaging than coal fired plants and have less impact on human health. Many of the natural gas plants are relatively new, thus retiring of coal plants would be a higher priority from an environmental and health standpoint. Coal currently generates more than 50% of the electricity in the
This entry was posted on Sunday, August 3rd, 2008 at 4:34 pm and is filed under Bad Science, Enviornment, Politics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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August 3rd, 2008 at 4:43 pm
Thanks for the article! I was looking at Honda’s Natural Gas Car yesterday (http://automobiles.honda.com/civic-gx/), and I was curious what the limitations were on the tech.
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August 3rd, 2008 at 5:03 pm
I don’t think there is any problem with NG(methane) as a fuel. Where I live tons of people use propane for their cars and trucks, and almost half the gass stations have propane.
Are there any significant diffirences between methane and propane as a fuel?
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August 3rd, 2008 at 5:43 pm
metatron said:
Well primarily that propane can be liquefied at reasonable pressure so that is how it is generally stored, which makes it a lot easier to store and also transfer to the vehicle. Propane comes both from natural gas sources and from petroleum refining. So it doesn’t really solve the problem that you start off with which is that it comes from natural gas which there is not enough of or petroleum which is what we’re trying to get rid of.
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August 3rd, 2008 at 5:55 pm
metatron said:
When methane is the gaseous fuel, the energy density on a volumetric basis is approximately 25% that of gasoline, propane is about 75%.
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August 3rd, 2008 at 7:55 pm
The Pickens plan is the biggest sham I’ve seen in a long time. Even if we could convert to 20% wind, it would take a long damn time. Even if we went 20% nuclear it would take at least a few years and probably a decade. That’s enough time to get drilling going in Alaska and offshore and to get synthetic fuel plants going to the point that it will make for mostly domestic production.
Long term the best policy is probably going to be more electric transport, but still we’d need a source for that electricity because the one we have now is worse than all the cars on the road to begin with. That’s the problem though is that the real solution is increased oil in the near term to get us out of this horrible situation with Islamic countries and long-term more nuclear energy to get baseload energy independence. No politician will agree to that. They want to pretend that wind/solar is how to go and pander to that myth just like they have for the past 30 years.
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August 3rd, 2008 at 10:28 pm
Synthetic fuel and expanded oil production domestically is the way to go for now because even if we move to plug-in hybrids and electrics consider the fact that it will take a few years to retool for that and then today’s cars will be on the road for a few more years ontop of that. Plus, consider that those with the least money will be the last to upgrade to new cars it’s a problem not to have reasonably priced and secure fuel for those needs. It will take many years to rewire all the railroads and to get all the cars replaced and trucks and heavy construction will need hydrocarbons for some time. Then consider the fact that aviation really has no alternative. The natural choice is to increase hydrocarbon production now.
It would not actually be as hard as it is made out to be. The oil companies have no incentive to do so without some kind of legislation to make it happen. The fact is that the oil refineries we have now already do things like cracking and hydrogenation and methanol production. We can convert these existing facilities to have greater synthetic fuel capabilities with relative ease by adding fluid bed reactors and more steam reforming. SASOL has good experience with this on a large level. It is energy intensive but I’d suggest a couple AP1000’s could provide the steam to drive the reactions pretty easily.
Petroleum is thought of as bad and almost sinful because it causes pollution. Bull****. Power plants are the elephant in the room (as it has been noted so many times). Also, if you’re so goddamned concerned about emissions from vehicles, then how about you stop destroying the economy and the income of the lower class and instead you go put out a goddamned coal seam fire!
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August 3rd, 2008 at 11:27 pm
Data points: The Meijer gas station a few miles away from me has a natural gas dispensing pump. I don’t know the current price, but a year ago the dial was set to what claimed to be $1.99 per galEq. (Gallon-equivalent of gasoline). I would guess that other Meijer gas stations have them as well, which should make long distance travel on methane possible if more expensive than it needs to be. For home heating, DTE Energy charges my household about 80 cents per 100 standard cubic feet, which works out as around $1 per galEq.
So, it’s already useful to have methane fuel capability. The problem is the cost of the vehicle modification. Refuelling every 50 miles might be worth a substantially reduced cost per mile, at least to me. Also, I would expect somewhat improved efficiencies due to the fact that the fuel is already a gas, eliminating atomization difficulties which occur with gasoline.
Filling propane cylinders as for cooking costs $20 for 17 pounds, which is about $7 per galEq. I have heard that large (100lb?) propane containers can be filled for considerably less, but I have no hard numbers here.
Coal was going for 60 cents/galEq (7 cents/lb) in Ohio a month ago. The person I talked to said that they expect to have to raise their prices 40% because of the increased cost of petroleum fuel used in mining the coal. This would bring the price up to 84 cents/galEq, or if used in a gasifier, effectively $1.26/galEq. I’d have to go about 75 miles to buy coal; but I figure I could carry enough for on the order of 2000 miles without undue inconvenience. (And it doesn’t need liquid-tight storage.)
The main issue with all of these fuels is getting my Engine Control Module to not freak out when it discovers that it has to reduce the injector pulse width to zero in order to get oxygen in the exhaust.
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August 4th, 2008 at 12:08 am
I’m not sure where you live but in the United States I’ve never seen a natural gas dispensing pump. If you think it would be no big deal becasue some gas stations carry CNG where you are, just try driving a diesel car. A large portion of gas stations have diesel but it’s still hard to always be sure you have a diesel station on your route. Now consider how much worse that would be with CNG and then the fact that you have to fill up every 50 miles.
Also the fact that it might be cheaper than gasoline would completely go away if a large portion of vehicles used CNG.
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August 4th, 2008 at 1:03 am
Natural gas is used a feedstock in the manufacture and delivery of essential consumer products and related services. The industry manufactures chemicals that serve as “building blocks” in making everything from plastics to clothing to medicine to computers and other products. They also contribute essential materials for making plastics, fertilizer, medicines, and many more key consumer products. It is also used to produce methanol and such substances as formaldehyde, acetic acid, and MTBE (methyl tertiary butyl ether) and as a propellant in sprays
All of these thing will become more expensive, as will more traditional uses such as heating if it is used as a transportation fuel.
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August 4th, 2008 at 2:32 am
Where I live, in Italy, there are two different networks for natural gas. Natural gas has been used in cars for more than 70 years since it was discovered in the Po valley. The biggest network sells liquefied propane and you can find it nearly everywhere. it is really easy and cheap to hack your car as the engine can run on LPG (500-1000€) and the tank is quite small (usually it fits in your spare wheel space). However it is cheaper only by 20-30% respect to normal gasoline and so if you are buying a new car it is not cheaper that a new diesel model.
The second network sells pure, gaseous CH4, and the methane station are a really different thing than petrol stations. They need completely different equipment, they are usually connected to the gas network and you can not refuel by yourself for security reasons. Where there is no gas network there are no gas station (and this is true for the south part of Italy, where there is no need of a gas network because there is little need of winter heating). Gaseous CH4 is a lot cheaper than gasoline (50% less) and also cheaper than diesel (20-30% less). But the tank are really huge and the range is not much (300-400 Km). You can buy a new car running on methane or refit your old car. It cost 1500-2000 € more but you get a refund from the State.
Having owned two methane cars I can say that it works (with some minor problems) but the price is closely linked to gasoline price, you often have to switch to run on regular gasoline, but you are forced to get a bigger car: there are some small car models but with really small tanks.
I am now thinking to get a smaller new car running on diesel (the costs are the same) and so should do the Americans, maybe
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August 4th, 2008 at 2:56 am
Fabio said:
You can get propane/lpg pretty readily in the United States. Natural gas is avaliable but not in many gas stations. There is a national gas network here as well and it is used for heating and so on.
I just don’t see the point in thinking it will somehow replace gasoline. It’s already shown that there’s not enough to make a big difference. Even if you save some money it’s still not going to make a national energy plan.
I don’t know you’d save with propane anyway. Propane is not necessarily less expensive. I know they have conversion kits for cars, but I do not see the point.
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August 4th, 2008 at 4:30 am
Burya Rubenstein said:
That’s interesting. I wonder if anyone ever uses the natural gas pumps? I think Meijer is only in the US midwest, so it would be of little help to those outside that area but I don’t know if other stations carry it?
It does not change the fact that it would not be useful as a national alternative to imported oil as the pickens plan wants us to believe. Also, I think propane is more common but as you say it sounds more expensive anyway. I do not know what the advantage would be of propane anyway.
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August 4th, 2008 at 11:43 am
If my memory serve me correctly, Pickens said in a recent interview that he wouldn’t be pushing this scheme if wind power and the required distribution system wasn’t subsidized by the tax payer and the rate payer.
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August 4th, 2008 at 12:28 pm
Harry said:
That’s the whole point. It’s about money and not in the sense of freeing America from imported oil, but in milking the tax payer for money on a system that could never stand on its own and is not actually productive enough to be supported by private investments and returns on the energy. It’s a shame to sell a big plan in the name of better energy policy when it’s just about collecting the generous subsidies!
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August 4th, 2008 at 3:06 pm
Natural gas is a Good Thing for the US. Not as a replacement for gasoline, but as a fuel for creating electricity. The economics of oil are that a small change in demand has a huge influence on price. A change of even 5% would be significant.
It is clean burning and readily available. The biggest problem with using natural gas for electricity generation is getting permits to build the plants and pipelines past the environmentalists. We use coal and diesel because environmentalists won’t allow us to use natural gas.
Gasoline is clearly the best solution currently for transportation.
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August 4th, 2008 at 7:31 pm
Chuck said:
The biggest issue with natural gas is pushing production wells down fast enough to meet demand. I don’t believe I have seen environmentalists freaking over gas too much, although there may be some local exceptions, as pipelines usually follow existing utility right-of-ways
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August 4th, 2008 at 8:35 pm
Natural gas (methane) as motor fuel is generally a bad idea. Not only is the volumetric energy density lousy, but also the mass based one if you include the tanks and so on. This alone would increase consumption in BTU per mile.
Add to that that methane is a fairly slow burning fuel compared to gasoline (and even slower compared to methanol or ethanol). The efficiency of an otto cycle engine depends on its compression ratio, which is fairly limited with gasoline, and marginally better with methane. But it also depends to a large extent on the burn speed. A slow burn speed means the mixture has to be ignited earlier to hit the peak pressure at about 15-20 degress ATDC. It also means some of the mixture is burning further down the power stroke, thereby not adding usable power. As a result the engine has a lower thermodynamic efficiency.
Vaporisation of liquid fuels is really not a problem, despite what all the snake-oil gas-saver ads say.
New engine developments, especially with alcohol fuels like methanol or ethanol, use direct fuel injection into the. The high latent heat of the alcohols cools down the air during the compression stroke. Thereby lowering the work used for compression and allowing much higher compression ratios. This of course has a direct effect on efficiency.
Methanol and Ethanol engines with thermodynamic efficiencies of over 43% have been demonstrated. This high efficiency operation is also achievable over a much wider load/rpm range than for gasoline or diesel. NG engines cannot take advantage of that and are here also much further limited in the achievable efficiency.
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August 4th, 2008 at 8:46 pm
This is the first result after 10 seconds on Google.
http://www.latimes.com/news/science/environment/la-me-power31-2008jul31,0,96741.story
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August 4th, 2008 at 8:58 pm
There’s nothing wrong with natural gas for a transport fuel any more than any other fuel. It works okay and for some applications like where there is a need to be more clean and low CO than other fuels things like propane and CNG might be the ticket. It has downsides too but it’s all relative.
The issue is that the Pickens plan which claims that CNG will somehow get the US off of forign oil is bull. Even if it were an ideal motor fuel it’s not like there is enough of it and it is already being imported. Also, it would have its own issues with raising the price of fertilizer or other products as mentioned.
Replacing gasoline with methane accomplishes nothing.
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August 4th, 2008 at 10:07 pm
Chuck said:
In general I see though that most environmentalists like gas more than other fuels. Naturally there will always be a few that will oppose anything without thinking, but in general when I search Google I see mostly support.
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August 4th, 2008 at 10:23 pm
I’d take a gas power plant over coal any day. Of course, I’m generally in favor of nuclear power to the greatest extent possible but where it’s necessary to have some extra plants for occasional peaking or possibly for times when nuclear reactors might need to do planned outages, then combined cycle natural gas is a decent choice. Really though I’d rather minimize it especially for base load. I’d prefer natural gas be primarily relegated to uses like as feedstock for chemical manufacture or for times when heating is required that is beyond the capacity of electric systems or heat pumps.
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August 4th, 2008 at 11:51 pm
Why would you want nuclear power? I know it’s good that it does not make carbon but still, the waste is the issue and as far as I see it it is just as bad and replaces one problem with another. Also, I know they say now it is safe and I think it probably is 99% of the time but the remaining, 1% or even less is not acceptable just because if a nuclear plant did blow up it would probably kill millions and make whole parts of the country uninhabitable for thousands of years. Plus, I think there has been a lot of talk about the fact that we’re go running out of uranium as is and that’s an issue too. Then what?
I read on here how solar is not as good as it seems. That’s not good and I see the point. But what else is there? Maybe if that is the way it is then we should just except that we will be causing damage with coal and gas but it’s all we have. So we should try to cut back as much as we can but if you ask me it is better then what a nuclear power plant could do to everything. It is not worth the risk. Maybe with cleaner coal and more damns and wind power and if we conserve enough we can get by. Nuclear is a last option that we should, I hope, never use. It is danger as it is.
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August 5th, 2008 at 1:22 am
David Lee said:
Nuclear power supplies a sixth of the world’s electricity. Along with hydropower (which supplies slightly more than a sixth), it is the major source of “carbon-free” energy today. The technology suffered growing pains, seared into the public’s mind by the Chernobyl and Three Mile Island accidents, but plants have demonstrated remarkable reliability and efficiency recently. And indeed, more than 20,000 megawatts of nuclear capacity have come online globally since 2000, mostly in the Far East.
As scary as the “what-if” scenarios for a nuclear reactor failure are, the reality has — so far — proved much less so. The World Health Organization (WHO) carried out several studies after the 1986 Chernobyl disaster; one, conducted 19 years later, concluded that 75 deaths could be directly attributed to the accident. Other WHO findings: 28 deaths among first-responders in the year after the accident could be directly linked to acute radiation sickness; there was a large increase in highly treatable thyroid cancers among young people and no clearly demonstrated increases in leukemia or other non-thyroid solid cancers; and the lifetime risk of cancer deaths among those exposed to Chernobyl radiation was about 3 to 4 percent higher than average. (You can find the complete digest report here.)
Furthermore, natural uranium resources are plentiful, secure, and expandable. In fact, there is 600 times more uranium in the ground than gold and there is as much uranium as tin. There has been no major new uranium exploration for 20 years, but at current consumption levels, known uranium reserves are predicted to last for 85 years. Geological estimates from the Organization for Economic Cooperation and Development (OECD) show that at least six times more uranium is extractable – enough for 500 years’ supply at current demand. Modern reactors can use thorium as a fuel and convert it into uranium – and there is three times more thorium in the ground than uranium. In addition, with the development of the next generation of nuclear technologies such as fast neutron reactors with closed fuel cycles, this figure rises to tens of thousands of years.
It should be pointed out that nuclear waste is solid, robust, self-contained, relatively small in volume and gets less toxic with time. Compared with other widely dispersed toxic materials like mercury, lead and PCBs, which have been responsible for large scale health problems, nuclear waste is pretty good, as waste goes.
Claims that geological sequestration is a technically challenging problem is just untrue. More than 1.5 billion years ago a nuclear fission reaction took place off and on – for hundreds of thousands of years in an underground uranium deposit in Oklo, Gabon, Africa. These natural reactors generated fission products very similar to those produced by modern nuclear power plants that have lying in Mother Nature’s repository for about a billion years. This provides remarkable evidence of the effectiveness of this method for the disposition of radioactive waste.
Technically, there appear to be no show stoppers for a considerable expansion of Nuclear Power throughout the world. It is a low carbon energy source with abundant fuel supplies. The technology works and has much potential for growth. And grow it will. the only question really is how far behind the countries that don’t want reactors wish to fall before they realizes this.
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August 5th, 2008 at 10:42 am
DV82XL said:
Yes, nuclear power and hydroelectric power are by far the two largest and most viable sources of carbon-free and sulfur/heavy metal/smog/nitrous free energy (and by the way I support the use of hydro power to the maximum extent reasonably possible, as long as it is within reasonable local enviornmental margins). However between nuclear and hydroelectric, which one has a **worse** record of catastrophic failures resulting in mass casualties and loss of property???
By far and away it’s hydroelectric. There are numerous examples of events which have claimed hundreds or thousands of lives in one swoop. There have also been numerous close-calls and narrowly averted disasters. There are also many facilities which are considered an eminent danger of failure
Can you imagine if this were the state of nuclear energy facilities? People are all up in arms every time a nuclear plant has a transformer fire or any kind of incident, no matter how minor! Meanwhile there are dams which are experiencing structural issues or seeing flood gates become stuck or jammed and areas evacuated due to concerns during heavy rains.
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