Electric cars are a pipe dream

Discussion in 'General Science & Technology' started by Syzygys, May 20, 2010.

  1. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    No. I can't accept your calling my 49% power plant conversion efficiency "pessimistic" when it is very generous - far above what is achievable with current coal-fired technology. There are 3 or 4 somewhat experimental super critical steam / coal fired power plants in China that may get significantly more than that 49%, but AFAIK, none in the USA, where coal still makes more than half of the Kwh produced. Here is how they measure power plant efficiency:

    "To express the efficiency of a generator or power plant as a percentage, divide the equivalent Btu content of a kWh of electricity (which is 3,412 Btu) by the heat rate. For example, if the heat rate is 10,140 Btu, the efficiency is 34%; if the heat rate is 7,500 Btu, the efficiency is 45%."

    From US's EIA: Table 8.2. "Average Tested Heat Rates by Prime Mover and Energy Source, 2007 -2011" at: http://www.eia.gov/electricity/annual/html/epa_08_02.html
    We see the most recent data (2011) that the average coal-fired power plant's "heat rate" in the US is: 10,128 Btu or 33.6% efficient, worse than England's 38% but "miles a way" from Electric's 60%, which must have been a "wild invention" trying to support the EV's. Also interesting to note, is that there has been little improvent in this well developed ~100 year old technology. I.e. in 2007 the average heat rate, according to the EIA was 10,158 or 10158 / 10128 is less than 0.3% while ICEs and cars using them are improving their efficiency by ~2.5% annually now, but of course that will slow as Carnot limits are approached and no more weight reduction can be made. Also important to note is that this modest improvement is ENTIRELY DUE to the closing of older coal fired plants - Excluding the super critical steam technology China is developing there is ZERO room for efficiency gains in the coal fired plant efficiency which has been refined for about 100 years.

    The US and England are doing quite well with this old technology. The global average efficiency of coal fired power plants is only 28%.

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    "State of the art" coal plants have only 45% efficiency vs. my assumed 49%.

    Chart from: http://www.worldcoal.org/coal-the-environment/coal-use-the-environment/improving-efficiencies/ which does have links to the ultra super critical power plants China is trying to develop. China does not, AFAIK tell their best efficiency - they only say that they produce 50% more electrical energy per ton of coal the China's existing power plants, which I quite sure get no more than 26% conversion efficient as they are old and obsolute designs. Thus China is claiming only 39% efficiency for the new technology under development.

    SUMMARY: I was NOT "pessimistic" I was very generous / optimistic as to what efficiency coal fired power plants can achieve.

    I have documented most of my statements, you and Electric have mainly just made pro-EV claims. I asked Elecrtic where was that 60% efficient power plant and what price they sold electric energy for. (Electric had said: "Efficiency of ~60% conversion of heat to electricity have been achieve in full size power plants.") but of course no reply was given as it does not exist.
     
    Last edited by a moderator: Aug 22, 2013
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  3. elte Valued Senior Member

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  5. billvon Valued Senior Member

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    Specifically I was talking about your 80% battery charge to discharge efficiency. That is pessimistic. The 49% is also somewhat pessimistic because while that is optimistic for straight thermal plants, not all our energy sources are straight thermal plants. Hydro, for example, is close to 90% - and makes up about 10% of our energy mix. Thus if you were assuming 49% for coal and natural gas plants you end up at 53% total system efficiency when you add in hydro. (Or if you were assuming 45% you end up at 50% - still higher than your claim.)

    Agreed - but you then assumed that 100% of our energy came from coal. That is a false assumption.

    And all you ever do is make unsupported pro-sugar-ethanol claims.

    IMO it is silly to assume that any one energy replacement (sugar ethanol, EV's, thorium reactors) will "replace" our current energy sources or transportation modes. In the future we will see a mix of fuel sources with a significant number of hybrids, CNG cars and EV's replacing many of the gas and diesel vehicles currently on the road. Hybrids will continue to grow in popularity. Even today EV's and PHEV's make up about 2% of all cars sold in California; this trend will continue until they make up a sizable chunk of the overall fleet.
     
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  7. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Coal? Fuck that! Look at how the US is in a methane boom, we should be burning more natural gas and less coal from an economical perspective, from ecological perspective we should be doing neither!
     
  8. billvon Valued Senior Member

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    I think that from an ecological perspective we should be using all that natural gas to run our cars. It's an easy short term solution. Keep the coal plants as baseline power while solar and wind provide opportunity power, then phase out the coal burners as nuclear power replaces them. At the same time, EV's and PHEV's will start reducing demand for gasoline and natural gas.
     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I agree with last paragraph, but what claim about sugar cane based alcohol exists that I have not well documented?

    Please read post 1436 of the Apocalypse Soon" thread before replying that it would not be possible for all the world's cars*, that still have IC engines to run on sugar cane alcohol, even if cellulosic alcohol does NOT prove to be economically competitive with fuels derive from petroleum. - Note that the crushed cane is very probably the most competitive source material for cellulosic alcohol as it is already at one point, where alcohol is being made, stored, and distributed, with zero cost of collecting cellulose from fields of switch grass, etc.

    * I do assume without proof that in the decade or so that would be required to replace gasoline powered cars, the acreage in sugar cane can be expanded to a few percent of earth's arable land and than food and fiber production can continue to expand also as much of the world has very poor agricultural practices - A "slash and burn then move on" approach to growing crops. Those two assumptions are basically political in nature, not technical nor limited by physics, etc.
     
  10. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Except all those fracked wells leak enough methane into the atmosphere to out do global warming by coal and then some.
     
  11. billvon Valued Senior Member

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    I agree it's not ideal - but methane has a much shorter half life in the atmosphere, and thus will be cleared much more rapidly than CO2 once we transition to a nuclear and renewables based energy system. (And overall is much cleaner than gasoline.)
     
  12. ElectricFetus Sanity going, going, gone Valued Senior Member

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    Like after the 22 century! For the mean time building more natural gas power plants with combine cycles and more electric cars to take advantage of them is the best answer? Why start building NG power cars when we are already going electric?
     
  13. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    I strongly agree. Global warming is increasing ocean evaporation (more floods now, worse weather extremes, more frequent weather related crop failures, etc.) but the longer term concern MAY be that the increase humidity and temperature may occasionally get the wet bulb temperature to 35C for a few days in a hot humid spell.

    Then every one not able to live in air-conditions rooms dies as humans, with their 37C bodies need to dump ~100W to the environment even just resting in a chair. No work can be done, not even slow walking as then they can't keep from over heating and dying with 35C wet bulb temperatures. Even the rich with air conditions will be dead soon if many die as the power lines will fail with no repairmen climbing poles, etc., food stores will not get food deliveries, etc. As Hansen put it: "not only will the arctic be ice free, the world will be human free."

    We really need to switch, ASAP, to renewable liquid fuels, like the only one demonstrated for 30+ years in Brazil to be both practical, and cheaper then gasoline for your car.
    Yes, but CH4 is more than 10 times worse GHG than CO2 and still far from concentrations needed to block all it can. (CO2 has 400ppm concentration and is already blocking 2/3 of the IR trying to escape that it can - i.e. in its absorption bands. I have not done the numbers but think a 5% increase in the current CH4 levels is far worse than a 100% increase in the CO2 atmospheric concentrations.)

    Also CH4, released at low altitude, say from frozen tundra or ocean floor hydrates,* has slightly more than a decade half-life. Until a few decades ago the atmospheric concentrations of CH4 were essentially static with release rate = destruction rates, but now CH4 is being released faster than it can be destroyed so the atmospheric concentration is increasing, and this is a positive feed back system.

    *BTW, there is more carbon stored in those hydrates and tundra than ALL the coal AND oil that ever existed on Earth! It is now bubbling up in the shallow Arctic ocean so fast that it forms "clouds" (some a mile in diameter) that submarine sonars can not see thru - like human is blind in an intense atmospheric fog. This is new - not experienced by WWII subs.

    PS if this post scares you, good. That was my intent -action, not words is needed now. Until something better and cheaper comes along, get on the "sugar cane bandwagon" now. For less than 1/5 of the cost of an EV's battery replacement, your existing car can be modified to use pure alcohol fuel. The military government in Brazil about 35 years ago MANDATED that service stations install alcohol pumps and all have had them for decades. US could give big tax incentives to do the same. With all its economic problems, the US can NOT afford a battery powered car fleet.
     
    Last edited by a moderator: Aug 22, 2013
  14. billvon Valued Senior Member

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    It's a better answer than coal - but is not the best answer. At best it is a stopgap.

    Because it helps us reduce CO2 and overall pollution in the meantime while reducing dependence on oil. (Note that drilling oil releases methane as well, so sticking to gasoline isn't a solution for methane releases either.)
     
  15. KitemanSA Registered Senior Member

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    Thing is, Thorium Reactors of the Liquid Fluoride type actually could. They probably won't immediately, but after a few decades...

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  16. KitemanSA Registered Senior Member

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    Except that methane is only cheaper than coal now because it is effectively illegal to export it. The world price for methane is some 4 times the US price. The prohibition against export may soon be lifted so the price will stailize at a much higher rate.
     
  17. billvon Valued Senior Member

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    So could solar, or coal, or natural gas, or wind, or even conventional LWR's. All are quite possible. Trying to do that (have one replacement for all our sources of power) would be foolish.
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I forget the details but the shipping terminal for at least one new exporter of LNG has been recently approved and several others are pending. I, however, think that before it can be built and functioning, huge volumes of LNG will be on its way to Japan, China and others in Asia from two new sources. Definitely from NW Australian waters where the world's largest ship now nearing completion will be moored. - Next to it (an LNG terminal with many "trains") the US's largest aircraft carriers look like large tug boats.

    US export of LNG will not be price competitive - tiny ships going thru Panama Canal or the very much longer trips to the Asian markets. I bet these new US export terminals go broke with rising interest rates on their construction loans. I.e. there will still be, if environmental concerns don't stop fracking for NG, cheaper than gasoline fuel NG for sale for decades in the US.

    The second potentially large supplier to the lucrative Asian markets is East African off shore wells. They too can ship quicker and cheaper than the US can.

    Note Shell has contracts already for the construction of three more copies of FLNG and if all goes well, will dominate the world's supply of cheap LNG with still more constructed. Also giving FLNG a cost advantage is fact there is no need to ship the NG to it via miles of pipelines - it is connected to the wells directly.

    One extremely important factor rarely mentioned is that FLNG is not damaged by political instabilities - it can always go elsewhere. It is the US's political stability (and pro-capitalism POV) that placed most of the world's oil refiners there - made the US an exporter of refined petroleum products for decades.
     
    Last edited by a moderator: Aug 23, 2013
  19. KitemanSA Registered Senior Member

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    Yes, but I meant realistically, i.e., economically.

    If there is one basic source that is actually much better that all the rest, and for which the fuel is prevalent and widely spread, why would it be foolish to use it exclusively? It would be foolish to MANDATE its use. But if all the current suppliers chose to convert to LFTRs, how is that foolish?
     
  20. billvon Valued Senior Member

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    All could do it realistically and economically. It would take a lot of effort in all cases. In all cases 100% reliance on one form of energy would be a bad thing.

    For the same reason it would have been foolish to rely 100% on the form of power which, in the 1950's, was going to be 'too cheap to meter.'
     
  21. KitemanSA Registered Senior Member

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    I seen no basis for that opinion.

    What, fusion? Heck, if it ever works and becomes more economical than everything else, why not rely on it? You seem to have a peculiar prejudice here.
     
  22. billvon Valued Senior Member

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    That you could rely 100% on one form of power, and that it would be realistic/economical/smart? Agreed.

    Yes; it is quite literally a prejudice, based on our past experience. Past reliance on one form of power has never worked out all that well; we don't learn about the problems until we are far too heavily invested in it. Thus I pre-judge that future reliance on one form of power will present similar problems.
     
  23. KitemanSA Registered Senior Member

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    624
    Nice reversal of meaning. Silly, but nifty too.



    Well, as long as you understand that your judgement is not anything that I must respect, ok.
    Of course, I fail to see any historical precedent for your judgement. When did we EVER rely on a single source of power? Since it is unprecedented, how can you judge it? Just curious.
     

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