The EROI on supplying fuel
Posted by Heading Out on November 28, 2007 - 11:00am
Topic: Demand/Consumption
Tags: fuel supply, human carrying capacity, Mayan drought, transportation [list all tags]
There have been a couple of comments this past week that lead me from the question of my last post – “what if it doesn’t get better?” into the sequel “how is it going to get worse?” Because if the presupposition is that there will be some cataclysmic event that will carry us into the next phase of our evolving reality, I am not sure that this will happen. And yet, without this impetus, and a focus for public and political attention, it becomes more difficult to get action, or recognition, of the urgency of the problem.
I can perhaps simplify a picture of this evolution by a simple example. You are a farmer in the less populated parts of the country, and you drive over to your local gas station, after noticing that you have less than three gallons of gas in your tank. You get there to find that the station has closed, and there is a note on the door that says that the nearest station is now 50 miles away. If you can make it to the station, and if your car gets 20 miles per gallon, you will now use a third of your tank of gas, each time you fill up, just in filling up your 15-gallon tank. (Until you also start filling gas cans).
As the price of delivery of fuel to remote stations increases, the first step that the operators take is to increase prices. As Leanan has posted, in Drumbeat, this increase in price causes problems, consider, for example, the Shetland Isles .
THE AVERAGE cost of a litre of unleaded petrol in the northern isles has rocketed to £1.15, while a litre of diesel costs £1.18. . . . . . . . He wants to persuade the government to cut fuel duty in peripheral areas, following the lead of other EU states such as Portugal, Greece and France.
As the story notes, governments in Europe are recognizing that there already exists a problem in supplying fuel to the more distant parts of their economies.
Similar increases in cost can also drive up local prices in places such as Bridgeport, CA
The Shell station in Bridgeport, a tourist town of 850 residents during the summertime peak, is charging $4.09 a gallon for regular. The outlet posted prices above the $4 mark at least four other times this year.Rosemary Glazier, who works in Bridgeport as Mono County's assistant finance director, is so irritated by the prices that she refuses to fill up at the local stations.
"It makes the whole town look bad," Glazier said of the $4-plus prices. Instead, she drives all the way to Gardnerville in Nevada, 62 miles north of Bridgeport, where gas is substantially cheaper.
Note that she is now driving a round trip of 124 miles (consuming what percentage of the gas in her tank one wonders) in order to fill (?) up. But at least, at present, she has the option to do either. The declining demand that comes from the increased price will reduce the profits of the dealers and station operators, in turn threatening their livelihoods. Consider the current case in Maine in the related fields of heating oil supply.
"The higher the price, the less the small oil companies are making," Porter said Wednesday. "It does impact you because it’s getting tougher for people to order larger quantities, and it costs me money to make smaller deliveries. My travel costs have almost doubled."
Porter said that customers who ordered 150-gallon deliveries last year have been ordering 100 gallons at a time this season. That results in his having to make a delivery stop every two weeks instead of every four weeks as in previous years. . . . . . . . As a way of cutting back on expenses, Porter has canceled all his advertising and is relying on word of mouth to market his product. He said he has been in contact with others in the oil business around the state, and their situation is just as bleak.
And so, as demand drops, and profitability disappears, so the neighborhood gas station will likely close, and one will have to drive further in order to fill one’s tank, and thus the energy cost of filling a tank will get higher.
This is not a problem that will impact the majority of Americans, the gas stations along the highways and in the cities and larger communities will not be as oppressed, and will likely retain profitability, rather it is the remoter parts of the land, where the food is grown, where this might first appear as a problem. This is not the problem that relates to refinery issues , but more to the simple economics of a small business. And it is difficult in the U.S., where there are not the tax burdens on fuel, to see the same sort of relief that is in existence in Europe.
One solution would be to accelerate the transition of vehicles to using higher percentages of ethanol, since that would at least provide a local source of fuel and reduce the need for the ethanol pipeline. But, as we are seeing, the immediate glamour of ethanol is fading, and in this regard I disagree with Richard Heinberg on the relative conflict between food and fuel, at this stage. The data from this and earlier years suggests that when the price of the crops start to go up, then the food demand can afford to pay a higher price than the fuel demand can, and so food, albeit at a slightly higher price, wins. As a result the economic incentive to run a bio-fuels refinery disappears, and without greater incentives, some of the refineries either close, or never get built. Of course, with a mandate for a certain percentage fuel, this does, in time lift the price of the remaining ethanol until an uneasy balance develops between the two, but I suspect it will be one that leaves our poor farmer still at that gas station trying to decide whether he can get to next town before he runs out of gas.
Many societies don’t have the luxury of the internal combustion engine to provide their supplies. R.B. Gill in his book on the Great Mayan Drought quotes Robert Drennan and Ross Hassig on the amount of food that a person can productively carry, over that which is consumed to provide the energy for the travel.
He estimated that a single human porter or tlameme as they were known in Nahuatl, could carry a load of about 25 kg (55 lb) of maize. He calculated, however, that the per day overburden of a porter, taking into account the nutritional needs of the porter and his family, was about 30% of the value of the load, based on a round trip for the porter. This places an absolute limit on the transportation of corn of 3.3 days or 100 km (60 miles). In other words, if a porter carried a load of corn 100 km, he would have used it all to feed himself and his family. The effective limit for a commercial distribution system, of course, would have been considerably less, say 50% of the absolute limit, or 50 km. During the Aztec dominance in the Mexican highlands, basic foodstuffs, other than gourmet items, were normally drawn from within a restricted radius of one day’s journey or approximately 30 km.
He goes on to quote Johann von Thunen on German economics, with a horse
He determined that the absolute trasportation limit for cereials carried by a horse and wagon was about 80 km. At that point, the horses and drivers would have eaten all the grain during the round trip.
It makes you appreciate the benefits of the coming of power., and the tremendous benefit in terms of food portability that it brings. But as that fuel availability diminishes, it also underscores the need to find alternative sources, since I am not sure that there is that much food grown within 30 km of any major U.S. city to feed its population.
"You are a farmer in the less populated parts of the country, and you drive over to your local gas station, after noticing that you have less than three gallons of gas in your tank. You get there to find that the station has closed, and there is a note on the door that says that the nearest station is now 50 miles away."
The region I farm in, the Mid South (Memphis)
will not have this problem.
Or the farmer won't. The farmer will convert to diesel or NatGas/Propane if gas is short.
There will be no shortage of diesel on the farm.
If there is, there will be a shortage of food in the city.
>The farmer will convert to diesel or NatGas/Propane if gas is short.
Right on the spot? Is he a transformer or something?
In Nepal, right now, there are diesel shortages on the farm.
Nepal is dependent on India, dependent on ....
The US produces a large part of all three sources (diesel, LP,
gasoline.
Make no mistake (sounding like a political hack here),
the US farmer will be hurt. But Suburbs and cities will
be hurting hardest and firstest.
;)
Yes.
Lift an LP tank into the back of the Pick Up, reattach
fuel line,
adjust the carburetor...
United States Patent 4413607
Link to this page:
http://www.freepatentsonline.com/4413607.html
Abstract:
A system for an existing combustion engine is provided for enabling the engine to be operated on liquefied propane, alone, through a conventional gasoline carburetor, to operate on either gasoline or liquefied propane through a conventional gasoline carburetor, to operate on liquefied propane, alone, through an inlet casting to be utilized in lieu of a conventional gasoline carburetor, or to operate on liquefied propane, alone, at a substantially constant engine speed. Further, the system is also operative in conjunction with a diesel engine whereby a small amount of gasified liquid propane may be introduced into the induction system of a diesel engine as a supplemental fuel charge therefor during high power demand periods of operation. The system includes a regulator-vaporizer assembly for reducing the pressure of and thus transferring liquid propane into gasified liquid propane, heating the propane gas and ducting the propane gas to an induction passage mixer, the latter including various adjustment features whereby the proper mixture of induction air and propane is afforded.
Take a day. And we're off. 8D
Very few cars & trucks still on the road have carburetors. They went out in the mid to late 1970s.
And I believe propane requires a new carburetor and not just adjustments to an existing one.
Propane through a modern, computer controlled car or truck, with not work without MAJOR factory level re-engineering.
Alan
I know that there are people that reprogram their automobile ROMs. I think that altering timing, pressure, and amount of fuel injection is not going to be a problem.
It's the fuel system plumbing that's going to be a problem for home rebuilders.
Why not just swap out the engine and fuel tank when your old system breaks down at 200K miles? Use a new system from GM or Chrysler or Toyota that is already designed for their model for that year? Just have them make a million cars and two million engines and fuel tanks.
Generally, by the time a vehicle's engine has worn out in normal use, so has much of the rest of the vehicle. It makes more sense to recycle it and build a whole new one, with all the improvements of the intervening time.
"And I believe propane requires a new carburetor and not just adjustments to an existing one."
That's correct. It's usually referred to as a "dry gas" carburetor. Popular with 4X4 off-roaders as it allows for the truck to operate at all sorts of extreme angles without starving it of gas like a normal carb/float system would. Also doesn't spew gas all over the place if you accidently flip it.
"Propane through a modern, computer controlled car or truck, with not work without MAJOR factory level re-engineering."
Ehhh. Well the original (gasoline) fuel injection assembly would most likely be useless. I can't say for sure though as I'm not sure of their flow capability, or whether they'd freeze from the pressure release, and the pressure regulation system would surely be useless. However, beyond that, a place like ZDyne can take a car's computer and re-write the coding to change the fuel injection duration (the fuel injector is just an on-off solenoid that raises and lowers a pintle either allowing fuel to flow, or disallowing fuel to flow...so on any cycle the length of time the pintle stays open is what matters). By changing the fuel injection mapping you can control the mixture. Or, (likely easier) you could disable the original fuel injection system (perhaps just using switches to turn off the injectors themselves, meaning you could turn them back on) and put a dry gas carburetor in behind the throttle body - the rest of the system should act the same (delivering spark at the correct time, etc).
So while likely technically feasible...in practice, a bit rediculous and I doubt some poor farmer is going to want to pony up $2,000 bucks or something for some kit to switch to propane on a whim.
That is what companies like Impco do for their dual-fuel systems. The gasoline injector systems do not have the pressure-handling capability to work with liquid propane, the thermal issues of the boiling liquid plus the reduced lubricating capacity would make injector compatibility an issue, and the system as a whole would be subject to vapor lock. The dual-fuel system Impco made some years back just hijacked the ECU inputs from the oxygen sensor to make it think everything was hunky dory, while using the signals from the mass-air sensor to control mixture in the optimum (lean of stoichiometric) range for propane (I'm not sure what they do to meet today's emissions regs).
Lean-burning a gaseous fuel like Hythane with a reasonably compatible flame speed might be fairly easy to do, but it would still require a second fuel system and a highly modified or secondary ECU to meet emissions. In other words, not a job for casual tinkerers working with off-the-shelf parts.
will there be "a shortage of food" if there is no NH3? if there is NH3, however, then you don't even need to convert to diesel or NG/propane.
by the way, NH3 can directly synthesized from heat/electricity rather than hydrocarbons or even H2.
NH3 directly from heat and electricity, with no hydrogen input?
So we're now putting Einstein's equation, E=mc2, to some practical use finally?
He was probably implying that one should use the eletricity to gather hydrogen, from water.
not necessary. in short, there are solid-state ammonia synthesis and thermal-chemical ammonia synthesis. neither needs to make H2 as a middle step. more can be found here.
Your link is broken - is this what you were referring to?
The linked method still requires hydrogen from electrolysis, but operates at relatively low temperatures, eliminating much of the additional energy overhead.
FWIW, the energy required for electrolysis isn't all that much. The energy required is quite close to the lower heating value of hydrogen, or about 300kJ/mol.
One mole of NH3 requires 1.5 moles of H2, or roughly 500kJ, and weighs 17g. To make the 80M tons of nitrogen fertilizer used per year, then, would require 80M x 1Mg/ton / 17g/mol x 500kJ = 650TWh, or about 4% of world electricity consumption.
So the energy requirements of fertilizer just aren't a big deal.
sorry for the broken link, here it is.
the point is that NH3 is also a clean (carbon-free) liquid fuel that can be readily used in various types of combustion engines. it has been done before (during the 1930s), extensively studied by the US army (involved people from UC Berkeley, GM and many other engine, vehicle and aviation companies) between 1960s and 70s and is being done right now by a small but steadily growing group of people.
The main problem with using ammonia for a fuel, particularly if done on a wide-scale basis, is that the combustion of ammonia produces various oxides of nitrogen (the exact type depending on specific combustion conditions). Nitrogen oxides (generally referred to as 'NOx') are a serious air pollutant, a major contributor to photochemical smog, and are now highly regulated, particularly in areas with poor air quality such as the Los Angeles
basin. The US auto industry has had to spend billions of dollars changing the designs of its internal combustion engines to reduce the amount of NOx formed as a natural part of high-temperature transient combustion conditions.
As a retired environmental engineer, there is no way that I can conceive of that the federal EPA and state environmental agencies would ever allow the widespread use of ammonia as a fuel. In fact, one of the concerns about using animal wastes as supplemental fuel is that it contains lots of ammonia and other nitrogenous compounds and thus produces high levels of NOx when burned.
Yes, I am aware that some rocket fuels contain nitrogen compounds, but the DOD and NASA have always had a sort of 'special dispensation' when it comes to certain evironmental regulations.
such concern may be unsubstantiated. rather to the contrary, if you read the various studies carried out in the 1960s and 70s by folks in UC Berkeley and GM, etc., ammonia combustion should produce far less NOx than produced by the combustion of hydrocarbons mainly because the peak temperature is lower in the ammonia fueled engines. another point is that the "state-of-art" method used by some high-end car makers in reducing NOx emission is to use urea - basically ammonia - to absorb the NOx. combustion of ammonia is never known to produce any NxO.
If your combustion temperature is lower, then you energy efficiency is lower, because that is the way the way engines work (thermodynamics). High engine efficiencies require high operating temperatures.
Without saying outright that NH3 is bogus, your respondants here are pointing out that there are a LOT of issues you have to address before this form of energy storage becomes credible.
are high peak temperature and efficiency of thermal-mechanical energy conversion so simply related? no matter how high the peak temperature goes, if the combustion is not ignited at the right moment due to self ignition or avoidance of knocking - as most of the gasoline engines do - the efficiency can remain very low.
no matter one doubts it or not, the fact remains that ammonia fueled cars, trucks, buses operated in Europe during WWII and that the fastest airplane ever existed was fueled by ammonia. to scientifically minded readers, there is a considerable body of work from the extensive investigations into the ammonia fuel applications performed between 1960s to 1980s funded by US army. one only needs to find and read them.
"Are high peak temperature and efficiency of thermal-mechanical energy conversion so simply related?"
Yes.
High temperature does not, of course, guarantee effficiency, only the converse: high efficiency is not possible without it. This is a basic law of thermodynamics: Look up the Carnot cycle and you should find a coherent explanation. The key point is that efficiency is constrained by the difference between burning temperature and exhaust gas temperature, and the greater the difference, the greater the possible efficiency. That said, this is indeed the reason engine manufacturers have always sought high compression ratios (and why high-octane gasoline, which burns hotter without exploding to make a knock is preferable to low-octane gasoline), and why diesel engines are inherently more efficient than gasoline engines.
Since I posted before, it has been posted that the amonia fueled-engines DO have high burn temperatures. This is good for efficiency, but brings us back to the problem of NOx in the exhaust gas. These gasses are poisonous and produce smog, and are an unavoidable consequence of high temperature burning. In defense of ammonia, let it be admitted that most of the nitrogen being turned into NOx will come from the atmosphere (which is 4/5 N2 to 1/5 O2) but the ammmonia itself will be adding a share, which hydrocarbons and alcohols do not.
Ammonia is highly, highly poisonous, so avoiding accidents is really important.
In modern industrial society ammonia is created using hydrocarbons to provide heat for the manufacture process. I don't think their is enough natural ammonia around to divert it from its vital role in food production and waste it as fuel.
... but only applies to heat engines. Electrochemical devices (batteries, fuel cells) have different constraints.
The problem with ammonia is that the nitrogen is a direct participant in the chemical reaction, so you're going to have atomic nitrogen up against oxygen radicals.
In NH3's defense, ammonia is also the preferred hydrogen source for NOx reduction catalysts. If you are fueling with ammonia, you won't have to worry about refilling an AdBlue tank.
Electrochemistry was mentioned as a possibility for production of ammonia--not, in this thread, for utilization. That would be an ammonia-powered fuel cell. If somebody invents one, that is a whole new subject.
So far, we have been talking about burning it in an internal combustion engine. The laws of thermodynamics apply. There is no way around this.
You said "high efficiency is not possible without it [high temperature]". I was just pointing out one of Nature's loopholes. And if the electrochemical ammonia production cell is reversible, it makes ammonia a far more useful fuel than it is with today's technology.
You will excuse me if I insist that I not be taken out of context.
"Are high peak temperature and efficiency of thermal-mechanical energy conversion so simply related?"
There is no ambiguity here: What do you think thermal-mechanical means, anyway?
And yes, maximum possible efficiency in an engine and difference between burn temperature and exhaust temperature are that simply related.
No, there are no loop-holes. Nature is not conned.
You deceive yourself to think otherwise.
When someone invents an ammonia fuel-cell, THEN we can talk about its pros and cons. If you are thinking of inventing one yourself, keep in mind that, your first constraint will be the electro-chemisty that makes a fuel-cell work. But from the standpoint of ease of storage and safety, ammonia lacks virtues.
Well, relative to hydrogen, ammonia is very easy to store. However, it shares many of the disadvantages of hydrogen including its low throughput efficiency if made from electricity.
Compared to hydrogen--you have agreement there! Hydrogen is so difficult to work with I often wonder why we are even discussing it. A very high-tech and unforgiving solution that I cannot believe will ever work.
Hydrogen comes up because the proponents of ammonia as fuel claim (rightly) that it stores more hydrogen per volume than liquid hydrogen and only requires cheap tankage. From this they conclude (wrongly) that it's a panacea.
it is a wrongly concluded statement that from this (storage advantage alone) they (the ammonia fuel advocates) concluded that it's a panacea (rather, it's considered a more practical, more immediate and more sustainable solution for both PO and ACC without the need to completely replace the existing infrastructure and equipment). any open minded reader can reach his or her own conclusion by looking into here.
Those reports have all the same flaws of the hydrogen advocacy: they ignore two critical facts:
We buy horribly expensive batteries for those applications where portability is key, but you'd never think of running your house lights on D cells. Neither are we going to build an ammonia-fuel infrastructure when Firefly Energy's lead-acid technology is good enough for the next 10 years and we can forego both the infrastructure costs and the conversion losses involved with chemical fuels of any kind.
Ironically, the Iowa State slideshow I linked shows why the near-term future will go to the PHEV. There's about 8 quads of energy in a typical corn crop (somewhat less than half of this in the cobs and stover). This pre-existing chemical energy will supply the chemical fuel required by PHEVs; the electricity produced from RE will supply the other 80% of the energy they need. There is no need to convert from electricity to chemical fuel and back, and the only way such a system can get going is with massive subsidies.
Considered by whom? Its partisans? Let's see, what new infrastructure would be required for RE-generated ammonia to replace petroleum motor fuel?
What new infrastructure is required for PHEVs? Roughly nothing, until they get well past 50% of the fleet; they leverage the existing electric infrastructure and add value to it in ways that ammonia never could.
You can be ignorant and think of ammonia as a serious possibility to replace petroleum motor fuels. But once you're knowledgable, that excuse is gone.
the "Those" and "they" are, again, wrongly concluded. people working on various aspects and scenarios of ammonia fuel applications are not organized. they have diverse motives and points of view. the link you provided reflects only one point of view. any one read through all the presentations (only then the conclusive "they" can be applied to the people who have expressed their opinions there) should be able to find the alleged ignorance unfounded.
no one disputes that "electricity used directly is far more efficient and attractive". the question is whether that is practical for all the applications of concern.
at least by some of the people advocating ammonia as fuel.
people advocate alternative fuels, ammonia among them, for different applications with different concerns - to some, satisfying the desire of continuing happy motoring and averting the possible accidental injury of some motorists due to fuel leakage may be of top concern; to others, avoiding the disruption in food production/distribution and preventing the almost certained death of many people due to starvation caused by such disruption are of paramount importance.
even if one assumes there is a straight electric powertrain that can outperform the ammonia powertrain in all prime movers, let alone ships and planes, by a factor of 3 to 6 in efficiency thus needs only 1/3 or 1/6 as much RE generation, it does not directly lead to the conclusion of only that much of RE generation capacity or infrastructure is needed. the amount of RE generation infrastructure needed has much to do with where they will be deployed. the difference, as can be easily seen on a global wind resource map, between some large areas on ocean and most areas on land can be more than 4 to 8 times in terms of W/m2.
that compare to the production of other means for energy storage unless the prime movers are grid-connected all the time.
you perhaps agree the existing ones are usable.
they can be underground or aboveground, pressurized or unpressurized. yes, new ones will need to be build.
can and should one reach such conclusion simply by drawing a parallel between a past experience during a resource-unconstrained era and one that is to take place in a resource-constrained future? besides, some, if not most, prime movers are already equipped with engines with high compression ratios.
why is that ammonia fuel needs an "entire new vehicle fleet" while PHEV needs "Roughly nothing"? does it also imply that the current FF power stations should just go on BAU?
the serious possibility to replace petroleum motor fuels with ammonia was practiced and confirmed in countries suffered the shortage of petroleum motor fuels during WWII. the consequence of being ignorant of this possibility and being unprepared for using it in a shortage of petroleum motor fuels could be very serious indeed.
should one jump to the conclusion that the combustion of NH3 will inevitably produce more NOx than that of hydrocarbon just because NH3 contains N? the answer from many careful studies is not. please read the article mentioned by Chris in his reply.
is ammonia poisonous? according to this expert (the number 3 presenter) it is Non-toxic: inhalation hazard only. one could also get frostbite if liquid ammonia comes to the direct contact with the body, of course, but yet again, that is not a toxic reaction.
it is the concern of the sustainability of this "modern industrial society" brought us here, isn't it? ammonia doesn't have to and should not come from hydrocarbons - as these resources are too precious (by the way, the main purpose of using hydrocarbons in making ammonia is not for the heat they produce but to get the H) - ammonia can be synthesized with just the renewable energy plus water (no need to be clean, fresh water as that is a scarce resource itself - on the other hand, combustion of ammonia will produce clean, potable water in return) and air. now comes to the question: is the current way of using ammonia as fertilizer sustainable? hasn't it caused severe environmental (especially in water ways and oceans by the run-offs) damage and soil organic degradation already? would it be better to use ammonia as fertilizer and the crop or other organic materials so produced as feedstock of biofuels or to use the organic materials as organic fertilizers and ammonia as a carbon-free fuel as suggested in here?
Inhalation hazard only. Sure. But that is the whole problem: You breathe it and it kills you.
In the accidents cited above, the survivors were just lucky. Not safe at all.
sounds like one whiff, you are dead kind of poison gas. but it is not. it is hazardous with prolonged exposure at and beyond certain level of concentration. in that category, one can enlist CO, CO2 and hydrocarbon such as CH4 and on and on - too many to list individually. one unique feature of ammonia is that it can be detected by human nose at an extremely low level of concentration. gaseous ammonia is also lighter than air at normal temperature. thus unless one is trapped in a closed environment with considerable amount of ammonia, the probability of fatality caused by ammonia should be lower than that long list of not so scary sounding and less odorous gases.
there is much danger in the easy way of life.
Ammonia smelling salts are still used to revive individuals who have fainted. BTW breathing Dihydrogen Monoxide can be fatal too, right? Ok, I not trying to make light of the potential hazards but as far as hazards go it's probably safest to avoid crashes in the first place.
John Holbrook sent me some papers on ammonia turbines yesterday. Thanks, NH3 for the introduction. The achieved temperatures were the same as for fossil fuels. The rate of fuel consumption was 2.4 time higher than for diesel and the power output about 10% higher.
I recall about 5 years ago many people insisting that jet fuel could not melt steel. The achievable temperature is not limited to the temperature at which a fuel burns in open air. Burning in heated air raises the temperature higher. One of the interesting things about ammonia is that the autoignition temperature is about 1200 F, rather higher than for gasoline (495 F) and higher that for hydrogen (1060 F), so compression ratios could be increased quite a bit using ammonia. The heat release per unit mass of stochiometric air is about 8% higher than for propane. Here, I'm citing Faehn, Bull and Shekleton (1966) Society of Automotive Engineers publication 660769.
It seems to me that the number of emissions to control with ammonia are fewer than for carbon based fuels and so catalytic converter design would be simpler. High power applications where fuel tank safety is not an issu