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Post by Barry Brook on Apr 30, 2012 22:04:26 GMT 9.5
A new guest post by Chris Uhlik has been published on BraveNewClimate. Link here: bravenewclimate.com/synthetic-hydrocarbons-futureIt concerns the transition from fossil to non-fossil hydrocarbon liquid fuels for transportation and related industries. This BNC Discussion Forum thread is for the comments related to this BNC post.
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Post by singletonengineer on Apr 30, 2012 22:22:03 GMT 9.5
Thanks, Chris and Barry.
This is a discussion which is past due. Although not elaborated on, the comment re the irrelevance of carbon sequestration is worth several reads - it is counter intuitive.
This short post could/should become a game changer.
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Post by Cyril R on May 1, 2012 1:48:45 GMT 9.5
If we can use Gen IV reactors, we can make a whole lotta liquid fuels: Of course it would be better to try to electrify everything we can first, since it is so much more efficient and cleaner. But there will be considerable liquid fuel demand left when all is said and done (think aircraft and long range shipping), and using coal to liquidsk, or ecosystem destroying biofuels, isn't an enticing prospect.
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Post by anonposter on May 1, 2012 2:00:11 GMT 9.5
Using overhead wires to power trucks isn't an idea I really like, on any route where you could justify freight electrification you should be running a railway line and if you want trucks to be electric stick them on the back of a train. The main problem with electric road vehicles is that you can't use pantographs (what is normally used on trains and trams) because there are two wires (since you need to return the current, a train or tram can use its steel wheels to send it to ground) and instead have to use trolley poles which are prone to dewiring (on well maintained systems it's uncommon, but better to avoid). I would instead replace most long distance trucking with electrified rail (whether inter-modal or rolling highway) and use synthetic fuels (along with probably some BEVs and hybrids) for the last kilometre stuff. EDIT: Cyril R: Large ships should have a nuclear reactor on them, then they'd have no need for any hydrocarbons, synthetic or otherwise, though aircraft are the one area where I don't think we can replace hydrocarbons (at least not without using something worse).
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Post by seth on May 1, 2012 3:56:34 GMT 9.5
Zero carbon ammonia is similar to propane in operation, but has half the BTU's per gal. An extensive ammonia distribution network already exists. It has issues all relatively minor compared to global warming.
You can Google the University of Texas's Electrogen machine – a low cost device that produces Hydrogen from electricity and water at $2.80/kg from 5c/kWH Electricity with their Ammonia machine. It uses the Hydrogen and adds Nitrogen to produce a carbon free liquid ammonia fuel at $ 0.80/gal on site. One cent a kwh electricity form the Denatured Molten Salt Reactor would reduce that number considerably.
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Post by darryl siemer on May 1, 2012 5:22:00 GMT 9.5
There are a couple of little boo boos in your post, Chris. First, US Portland cement consumption currently averages about 100 million tons per year which corresponds to ~1.05e12 gram moles of limestone-carbon/year, not 5.45 e12 moles/year. The total amount of CO2 released in producing that much cement would be about twice that much (~2e12 gram moles) because current cement manufacturing processes invariably utilize low grade carbonaceous fuels – mostly coal. Second, the numbers in your drawing/figure suggest that about 72% of “our” petroleum is used as motor (transportation) fuel, not 46%.
Barry featured my opinions about future synfuels in a post ("Nuclear Ammonia") last October; i.e., I feel that most of it should be ammonia & the remainder gasoline made with hydrogen and carbon dioxide derived from the nuclear-powered manufacture of cement.
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Post by Chris Uhlik on May 1, 2012 6:15:49 GMT 9.5
There are a couple of little boo boos in your post, Chris. First, ... Second, the numbers in your drawing/figure suggest that about 72% of “our” petroleum is used as motor (transportation) fuel, not 46%. Right! I should have said only 46% ends up as gasoline for light vehicles. I guess my point there is that short range (less than 200 miles) battery EV technology will not offset as much fossil carbon as most people think because gasoline is really a small share of atmospheric carbon. On the point about Limestone / Cement, I think I took care of the coal component by counting overall coal production. And yes, I wouldn't be surprised if my CO2 from Limestone is off by a factor of 2 or more. If you know more about the chemistry of cement production, perhaps you can educate us --- I'd like to correct my calculation. Thanks, Chris
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Post by Chris Uhlik on May 1, 2012 6:25:52 GMT 9.5
Using overhead wires to power trucks isn't an idea I really like, on any route where you could justify freight electrification you should be running a railway line and if you want trucks to be electric stick them on the back of a train. [...] I would instead replace most long distance trucking with electrified rail (whether inter-modal or rolling highway) and use synthetic fuels (along with probably some BEVs and hybrids) for the last kilometre stuff. I like that solution where it is applicable, but new rights of way and new rail lines are expensive / difficult / sometimes impossible. On the other hand, adding one lane of overhead electrical power to the US Interstate Highway system (and the major train routes) is something that could be accomplished in just a year or two with a relatively modest budget. And, it would be completely backward compatible with the current system (as is piggyback train transport where available now). If the government made the investment to electrify the highways, new tractors would be deployed wherever operating costs were substantially lower. Personally, I think this is some of the lowest-hanging fruit for decarbonization / alleviating fossil petroleum demand. Electrifying the Interstate Highway system could reduce oil demand more than drilling in Anwar would increase oil supply. EDIT: Cyril R: Large ships should have a nuclear reactor on them, then they'd have no need for any hydrocarbons, synthetic or otherwise, though aircraft are the one area where I don't think we can replace hydrocarbons (at least not without using something worse). That was item 7, nuclear powered container shipping. I suppose large ore carriers (and oil tankers?) should also be nuclear powered.
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Post by Chris Uhlik on May 1, 2012 6:31:52 GMT 9.5
Zero carbon ammonia is similar to propane in operation, but has half the BTU's per gal. An extensive ammonia distribution network already exists. It has issues all relatively minor compared to global warming. Yes, carbon-free liquid fuels are another important route to lowering fossil carbon demand. I guess I should have said there are 3 ways to (simultaneously) proceed: Chris
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Post by anonposter on May 1, 2012 9:18:31 GMT 9.5
I like that solution where it is applicable, but new rights of way and new rail lines are expensive / difficult / sometimes impossible. Over long distances with mostly empty land it shouldn't be too much of a problem (and the routes that have the most trucking now probably also have railway lines, I know Melbourne–Sydney (the Hume has a lot of trucks on it and talk of allowing larger trucks) does). On the other hand, adding one lane of overhead electrical power to the US Interstate Highway system (and the major train routes) is something that could be accomplished in just a year or two with a relatively modest budget. Though you'll end up restricting trucks to travelling in that lane the whole trip and you'll have need a lot more trucks than you trains (thus higher operating costs due to increase wear and tear on the overhead (added to trolley poles putting more wear on the overhead and such overhead being more expensive) and it'll also carry a lot less freight). If you're going to take a lane away from cars you may as well just remove the inner lanes and stick double track in the median. Overhead wires for road vehicles only really seems to make sense in mountainous areas where the superior hill climbing ability of trolleybuses over trams would be needed. That was item 7, nuclear powered container shipping. I suppose large ore carriers (and oil tankers?) should also be nuclear powered. Yes, though oil would probably be better off being manufactured nearer to where it is used with high temperature GenIV reactors (or maybe even renewables, synfuel production is less intolerant of intermittent sources). Yes, carbon-free liquid fuels are another important route to lowering fossil carbon demand. I personally wouldn't care if they carbon or not, just so long as whether the production process was carbon neutral (so that if you took all the carbon from the atmosphere or sea it would be OK). I guess I should have said there are 3 ways to (simultaneously) proceed: Of course how economics of the non-carbon fuels compared with the synthetic hydrocarbons will be the big issue here. From what I've heard it sounds like we could get carbon neutral synthetic hydrocarbons at an acceptable price (and hydrocarbon fuels do have their advantages). I also don't really like the idea of 50 L of toxic cryogenic substances (which will become gaseous if spilled) in every car (I could propose worse things though). BTW: List only seems to allow bullet points.
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Post by David B. Benson on May 1, 2012 14:28:05 GMT 9.5
Railroads can become congested. For example, there are currently 3 routes from Spokane to the Puget Sound area. The best one, with along tunnel, is 100% utilized right now. The next best, with a shorter tunnel, is only about 30% utilized as grades exceed 2.8%. The third best is a water grade route but goes down to Vancouver, WA, and then back north; the long way around. It is already about 70% utilized, at least as far as Vancouver/Longview.
So without reopening the Snoqualmie Pass tunnel there is little prospect for replacing the vast flow of road freight by utilizing trains. The railroad in question, BNSF, has stated they have no intention of adding track, drilling another tunnel on the best route, or reopening the tunnel on a 2.8+% grade route unless the State of Washington wants to pay for it.
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Post by harrywr2 on May 1, 2012 15:08:33 GMT 9.5
I'll nitpick the cement numbers as well. They are not a function of GDP. US Consumption of cement is about 5% of the global total which would roughly track global 'per capita' cement consumption. Even using 'per capita' is fraught with exceptions. The Chinese are consuming cement at more then double the US 'per capita' rate. www.japanprobe.com/2008/06/19/cement-use-by-country/
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Post by Robert on May 2, 2012 9:06:58 GMT 9.5
What about sunlight-to-liquid fuels? A project at Sandia aims for 10% overall efficiency of using sunlight to split CO2 and H2O into CO and H2 which are then reacted in a standard way to produce liquid fuels. I think they have a test reactor with 1% efficiency already. This must be intrinsically more efficient - produce more liquid fuel per square meter -than growing grass. For that matter you could use energy from a nuclear power station to drive the same process.
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Post by JeremyG on May 2, 2012 12:07:47 GMT 9.5
Depending on your timescale, you can put limestone->cement in the carbon-neutral category, as the cement will weather back to carbonates a lot faster than biosequestration makes oil, coal and gas. Closed-cycle nuclear process heat and electricity (or perhaps solar furnace if the cost/scale weren't so horrendous), + S-I process, + reverse water-gas shift reaction, + Fischer-Tropsch, at least as far as dimethyl ether, + CO2 capture on atomic-powered limestone kilning, seems like the way to go for applications that can't do without carbon-based fuel. The limestone->cement and aviation carbon release and consumption are conveniently similar in magnitude. As others have noted, some mix of electrification, fission propulsion, ammonia, and maybe boron, should cover the rest of transport in the absence of the big 3 fossil fuels.
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Post by anonposter on May 2, 2012 12:34:48 GMT 9.5
Depending on your timescale, you can put limestone->cement in the carbon-neutral category, as the cement will weather back to carbonates a lot faster than biosequestration makes oil, coal and gas. Quite a lot of our buildings will probably still be standing in 100 years (and even more so with infrastructure like bridges).
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Post by LancedDendrite on May 2, 2012 14:59:04 GMT 9.5
Railroads can become congested. For example, there are currently 3 routes from Spokane to the Puget Sound area. The best one, with along tunnel, is 100% utilized right now. The next best, with a shorter tunnel, is only about 30% utilized as grades exceed 2.8%. Well, if you electrify that 'second-best' route you can use electric locomotives which have much higher peak power outputs and power-weight ratios. In general, I would state that the following things are what deliver approximately the best cost-benefit for decarbonising in descending order: - Replace coal power with nuclear power
- Increased investment in electrified public transport (trains, hybrid buses, trams/streetcars) to encourage migration away from regular car use
- Peak electricity demand reduction, domestic heat pumps and electrified cooking - all to reduce natural gas demand and peak electricity usage
- Electrified freight rail with better train frequencies to encourage migration away from long-distance road haulage
- Electric cars and long-range road transport
- Electrified metal refining and production and recycling
- Nuclear cargo and bulk ore shipping
- Synthetic petrochemicals for remaining transport fuels (aviation primarily) and plastics
- Long-range (up to 800 km between major cities) High Speed Rail in order to reduce domestic aviation demand (in larger countries outside of Europe mainly)
I'm pretty much restating what others have said, but it helps to show what is sensible and how it all fits in. Excellent blog post by the way, Mr. Uhlik.
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Post by max on May 2, 2012 16:17:22 GMT 9.5
An excellent choice would be synthetic methanol. It can be used as a transportation fuel and as the basis for more complex hydrocarbons (plastics), which will still be in demand in a post fossil fuel economy. First generation methanol would be derived from biomass, second generation methanol from hydrogen reacted with flue gas and biomass CO2, while third generation methanol production would directly capture the required CO2 from the air. I recommend the book "The Methanol Economy" by George Olah to anyone who is interested in replacements for fossil oil and gas. Switching to methanol would require relatively modest changes to our current infrastructure, since it is mostly compatible with current refueling equipment, unlike hydrogen. The most efficient use of methanol as an energy carrier would be in a direct methanol fuel cell, driving an electric motor. However, at the moment, these fuel cells are even more expensive than hydrogen fuel cells because they require the use of a platinum-rhutenium catalyst to draw hydrogen atoms directly from the methanol. Well, maybe Planetary Resources will drive down the price of platinum group metals far enough in the future to allow them to replace ICEs on a large scale!
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Post by max on May 2, 2012 16:26:06 GMT 9.5
I see that nuclear cargo shipping is mentioned quite frequently. I disagree that it will play a major role in a zero-carbon future for political as well as environmental reasons. Imagine the public outcry if a nuclear freighter got in the hands of Somali pirates (or al-Qaida) or sank after being smashed by a towering freak wave on the open ocean.
My bet is that oceanic shipping will increasingly switch to LNG in the coming decades (which can later be synthesized) and we'll see a return of the sail as auxiliary propulsion system.
For the East Asia - Europe trade, transcontinental freight rail may also take up an increasing share of the market (from virtually zero right now), if the Chinese plans regarding rail network expansion in Central Asia are realized. Depends on the price of electricity and the price of synfuels though ... in general ships are more energy efficient than trains.
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Post by anonposter on May 2, 2012 16:32:08 GMT 9.5
Methanol would work though you'd have much the same problems as ethanol does with regard to engine and pipeline compatibility (solvable, but you won't be running your classic car on it (unless it's a Model T Ford)). Methanol would work pretty well with fuel cells though on-board reforming would make things easier.
Also I'd try to avoid biomass where possible, we should be growing crops to feed people, not SUVs (yes, I happen to think we're better off digging up oil than trying to grow it).
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Post by anonposter on May 2, 2012 16:46:44 GMT 9.5
I see that nuclear cargo shipping is mentioned quite frequently. I disagree that it will play a major role in a zero-carbon future for political as well as environmental reasons. Once the anti-nuclear movement is defeated sufficiently for us to solve the biggest part of global warming you'll see opposition to nuclear powered ships disappear (and there are already nuclear powered civilian ships used where fossil fuels can't do the job (i.e. serious icebreaking)). Some countries currently won't allow nuclear powered ships in their ports but increasingly as global warming becomes more of a concern it'll be fossil fuel powered ships which end up banned (and until all the irrational bans are repealed there'll still be plenty of routes where both ends allow nuclear powered ships). Imagine the public outcry if a nuclear freighter got in the hands of Somali pirates (or al-Qaida) or sank after being smashed by a towering freak wave on the open ocean. Less environmental impact than fossil fuel powered ships, I hardly see any reason for such public outcry (nuclear submarines have sank before and it hasn't ended the world (diesel fuel is much more likely to spill and cause problems). My bet is that oceanic shipping will increasingly switch to LNG in the coming decades (which can later be synthesized) LNG would require big tanks due to its low volume along with limited the range and speed of the ship (nuclear powered freighters would be able to go faster and still get the same economics). and we'll see a return of the sail as auxiliary propulsion system. I'd be surprised if sails actually do make a big comeback (some experiments and a little greenwashing, yes, but being fitted to every container ship, no). For the East Asia - Europe trade, transcontinental freight rail may also take up an increasing share of the market (from virtually zero right now), if the Chinese plans regarding rail network expansion in Central Asia are realized. You'd probably run much of it along the trans-Siberian (though then you get a break of gauge at each end but if you're using containers that shouldn't be too much of an issue). Depends on the price of electricity and the price of synfuels though ... in general ships are more energy efficient than trains. Actually ships and trains are about the same (though trains are a bit faster). Though rail does need a lot of fixed infrastructure.
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Post by John ONeill on May 2, 2012 16:55:46 GMT 9.5
Aviation is supposed to be about two and a half times worse for global warming than equivalent ground level fossil fuel users, because it puts water vapour and nitrous oxide into the lower stratosphere. It is also already very much affected by oil price rises, with fuel costs making up about half of airline running costs, even without any fuel taxes or carbon taxes. The first molten salt reactor was designed for aircraft use, but was cancelled partly because, even with a mass of shielding nearly as heavy as the reactor, radiation levels for the aircrew were unacceptable. Radiation would also affect electronics and components such as tires. If small modular molten salt reactors become readily available and cheap in the next few decades, it is conceivable they could power drones to tow airliners across the oceans, linking up outside the continental shelf, staying high enough not to irradiate the ocean below, and using long enough tow lines to keep the towed aircraft safe. Current aircraft would only need to be retrofitted with a tow point near the front undercarriage, and probably an upgraded auxiliary power unit, and would only have to carry enough fuel for takeoff, climb, landing, and a safety reserve to reach an airport from any point on the route. The tug would only have to land every month or so, possibly at a remote military airport or maybe even as a seaplane. Cooling after an emergency shut down would be automatic- the thing would be in the ocean in about two minutes. Flights over populated land would be a bit controversial
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Post by anonposter on May 2, 2012 17:18:25 GMT 9.5
The first molten salt reactor was designed for aircraft use, but was cancelled partly because, even with a mass of shielding nearly as heavy as the reactor, radiation levels for the aircrew were unacceptable. Not true, they very much could get radiation levels for the aircrew down low enough, the problem was that they would have to use a shadow shield so that those around the plane would get higher doses, this means that any nuclear powered aircraft would have to be towed out to the runway with the reactor shut down, then all ground crew would need to be moved away from the plane before it takes off and it'd need to be able to its take-off and landing approaches over desert. The military could have tolerated such restrictions and maybe if ANP had been competently managed might have done exactly that but civil aviation couldn't tolerate that (and the military are probably better off with in-flight refuelling). Radiation would also affect electronics and components such as tires. The RAD750 could handle the radiation with no problem. If small modular molten salt reactors become readily available and cheap in the next few decades, it is conceivable they could power drones to tow airliners across the oceans, linking up outside the continental shelf, staying high enough not to irradiate the ocean below, and using long enough tow lines to keep the towed aircraft safe. Makes cleaner burning synthetic hydrocarbons sound like a damn good idea to me.
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Post by John ONeill on May 2, 2012 20:34:14 GMT 9.5
How would synthetic hydrocarbons burn any cleaner? reducing the engine temperatures might cut NOX but would probably reduce fuel efficiency, and if high altitude water vapour is a problem even burning pure hydrogen wouldn't help. ( I figured radiation hardening of electronics would have advanced a lot since the fifties) One simple way to cut aircraft greenhouse effects would be to reduce night flights. Vapour trails reflect sunlight by day, but trap heat at night.
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Post by anonposter on May 3, 2012 6:32:37 GMT 9.5
By not having as much sulphur and other crap in them (you could make the petrol, diesel or kerosene much purer than you could refining from natural sources).
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Post by LancedDendrite on May 3, 2012 10:41:39 GMT 9.5
I see that nuclear cargo shipping is mentioned quite frequently. I disagree that it will play a major role in a zero-carbon future for political as well as environmental reasons. Imagine the public outcry if a nuclear freighter got in the hands of Somali pirates (or al-Qaida) or sank after being smashed by a towering freak wave on the open ocean. The advantage of a nuclear-powered cargo ship is that fuel consumption is practically decoupled from the speed of the ship - if a nuclear-powered aircraft carrier like the Nimitz Class can do over 30 knots and existing intermodal container ships can go 21-25 knots, you could easily plug in a nuclear reactor with enough fuel to last the entire life of the ship (25-30 years) and enough power to propel it at 30 knots. Once you get to 30 knots you have a ship that could possibly run fast enough to avoid pirates in places like in the Red Sea. As for terrorism, if you have a reactor that is essentially sealed up for the life of the ship and mostly automated, it wouldn't be a good target at all. And those speeds will allow for more time-sensitive freight and makes each ship more productive. This where a Denatured Molten Salt Reactor would be perfect. You have enough fuel in the salt to last the life of the ship, depleted uranium salt tanks for emergency denaturing to eliminate concerns about proliferation and so on. Load it up with U-233 and U-235 when you commission the ship, take it out when you lay it up. Another extra advantage of nuclear propulsion is that you don't need smoke-stacks, so you can maximise the amount of deck area for containers. Ultimately the thing that brings this all down are the regulatory and personnel barriers - you would need crews with higher training than they have currently. Still, it's an area that has great promise.
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Post by anonposter on May 3, 2012 11:10:16 GMT 9.5
Maybe I should just link to some of Rod Adam's writing on nuclear ships. This where a Denatured Molten Salt Reactor would be perfect. You have enough fuel in the salt to last the life of the ship, depleted uranium salt tanks for emergency denaturing to eliminate concerns about proliferation and so on. Load it up with U-233 and U-235 when you commission the ship, take it out when you lay it up. Some have suggested that heterogeneous reactors may be better for marine propulsion due to being able to have the fuel in a water insoluble form. Another extra advantage of nuclear propulsion is that you don't need smoke-stacks, so you can maximise the amount of deck area for containers. Not just that, but for long distances the fuel can be a significant proportion of the ships displacement (and some trade routes require you to carry fuel for both ways, big shipping companies have a whole department dedicated to optimising where their ships are refuelled). Ultimately the thing that brings this all down are the regulatory and personnel barriers - you would need crews with higher training than they have currently. Still, it's an area that has great promise. An inherently safe reactor shouldn't require much more training than a diesel engine and once the anti-nuclear movement loses power I'm sure the regulatory problems will disappear.
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Post by John ONeill on May 3, 2012 19:51:36 GMT 9.5
'By not having as much sulphur and other crap in them (you could make the petrol, diesel or kerosene much purer than you could refining from natural sources).'
Sulphur is already below 600 parts per million, and anyway sulphur dioxide causes cooling. It's the carbon and hydrogen that constitute 99.9% percent of hydrocarbons, and the nitrogen you have to burn them in, that are heating the climate.
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Post by anonposter on May 4, 2012 8:49:59 GMT 9.5
Sulphur dioxide also causes acid rain (and appears to provide extra nucleation sites allowing contrail formation, though switching to lower sulphur fuel doesn't seem to help much if at all with contrails).
Dropping to lower altitude could reduce contrail formation but at the expense of increased fuel usage (though if the carbon for the fuel is from a carbon-neutral source that might be a net gain, NOx emissions have been steadily dropping as engine technology advances so we should expect that to continue).
Putting chlorosulfonic acid in the exhaust can also stop contrail formation but that's probably not something that'll be happening outside the military (even in the military they try to avoid it if they can).
If we had to to we could probably pull more CO2 out of the atmosphere than we need to make jet fuel and then just sequester the excess to offset the effect of the contrails.
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Post by jagdish on May 5, 2012 20:32:29 GMT 9.5
Nuclear power is already being used 1. In power production. This could be maximized to reduce CO2 due to burning of fossil fuel and to conserve them for a longer period. 2. In running of submarines and Russian ice-breakers. This could be extended to all bigger ships. 3. Mobile floating power stations by Russia. Extension could reduce NIMBY resistance and delays. Less of coal should be mined. Techniques like underground gasification could be used starting with deep mines and high ash coals, to produce gas input for synthetic fuels, if and when they become necessary or economically feasible. Storage of gas requires big volumes. A tip should be borrowed from another fuel gas, acetylene, which is stored as a solution in acetone. Suitable solvent for methane should be developed so that it can be stored and transported more safely at lower pressures. Uses of methane in solution could also be developed as solvents like acetone are best disposed off as part of fuel. With right decisions, present or slightly modified technology could go a long way. For nuclear energy, IFR or equivalents are required.
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Post by keithpickering on May 11, 2012 9:40:37 GMT 9.5
I'm seeing the numbers in this posting as far too pessimistic. For miscanthus, yields at three test plots in Illinois were between 2.2 and 3.5 kg/m², three to five times higher than the 0.7 used here. Accordingly, we could replace the entire US fossil gasoline use with about one Kansas, not five: 12.5% of US arable land, assuming 3 km/m². The US currently exports about half our grain crop, so this is entirely feasible. Also the most desirable areas for miscanthus production (the Deep South, due to its long growing season and high rainfall) are not well suited to production of grains; instead, displacement of cotton and tobacco would be the most likely outcome, mitigating the loss of food production. The other thing to consider is that the introduction of a new, high-profit cash crop would spur the re-planting of currently disused acreage.
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