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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    23,198
    I think you have neglected a significant loss: When you charge a battery, you must supply higher terminal voltage, Vt, than the battery produces, Vb, when there is no charging or discharging current. The difference Vt-Vb is greater the faster you want to recharge and is 100% loss. I.e. the fraction of the energy applied that is being converted to heat is: (Vt-Vb)/Vb and can be 10% with charging at the typical not over night recharge. (Slowly recharging is more efficient.)

    Likewise due the fact that the battery has "internal resistance" when you take energy out, more heat is generated (the RI^2 loss). As is clearly evident in that expression this loss is quadratic in the rate of discharge. (Actually greater than quadratic as the internal resistance, R, also increases with rate of discharge. - Crudely, as a typical case, pulling 2I instead of only I from the battery when the car wants more power, will increase the losses by at least a factor of 5.) If you have a "light foot" on the accelerator most of the time, this loss may be only 3 or 4% of the stored energy; but if you like the fact that an electric car has high torque capacity, even when just pulling a way from the stop light, and "burn a lot of rubber" then to impress others and you do a lot of passing, then the high current discharge losses can also eat up 10% of the stored energy by heat production.

    SUMMARY: Perhaps for the "typical" driver the total "in&out" of battery losses are ~15%, which you have neglected. Thus, over all efficiency in use of the fuel energy at power plant is: 0.4x0.93x0.85x0.95 = 0.30 (bold factor is the one you forgot) so there is little, if any, energy saved compared to just burning a liquid fuel in an IC motor.

    The all electric car could reduce the CO2 release to the extent that the wind, sun or nuclear are generating the recharge power, when compared to any fossil fuel (gasoline or natural gas) but the sugar-cane alcohol fuel reduction in CO2 is much greater. The net energy gain for that fuel is about 8, so about 12% of its produced energy was used to produce it and released CO2 (assuming that fossil fuels were used to plant the cane, harvest it, and haul it the fermentation / distillation plant). One should note; however, that there is much more energy released by burning the crushed cane than needed to run the distillation process. This excess energy is increasing used in Brazil to make electric power - about 4% of all Brazil's electrical energy now, but soon to be at least 5% as more distillation plants add electric generation capacity.

    To make a numerical comparison for better understanding, assume assume solar & nuclear generation produced 50% of the recharge energy. As far as the CO2 release is concerned, that is like doubling the overall efficiency from 0.30 to 0.60 so compared to the fossil fuel IC car's 100% CO2 production form the carbon in the fuel (not as much carbon in the fuel for same energy if fuel is natural gas) we have at 60% effective efficiency (for CO2 considerations) or 40% reduction in CO2 with the electric car vs the fossil fuel IC car; however an 88% reduction if that IC motor is running on sugar cane alcohol, not even including the 4% reduction of power genertion in the CO2 released to make electricity (because that 4% saving, in Brazil does not displace much fossil fuel as most of Brazil's electric power is hydro-electric power)

    SUMMARY: The all electric car (with half the charging energy made by fossil fuel) does reduce CO2 release by ~40% compared to car using gasoline IC motor, but if that IC motor is running on sugar-cane alcohol the reduction in CO2 release is at least twice as great.

    Again, I point out that if the global mobile fuel were mainly tropical alcohol, many low skill jobs would be produced, but sending billions to Arab oil producers produces very few jobs, except it does pay the wages of a lot of terrorist (opium production may pay a great fraction - but that has additional cost to western societies and greater efforts should be directed towards elimination of opium production.) I again also note, that even with clearing of some tropical forests, etc. it is not possible for sugar cane alcohol to support the current inefficient transport system. More public transport, and much more "telecommuting", special express lanes for 3 person car pools, less heavy cars, and far fewer of them, with regenerative breaking, etc. are essential before the world can get off the petroleum tit and reduce the CO2 release more than twice as much as is possible with 100% switch to expensive electric cars, many of which would still need a liquid fuel, which should be tropical sugar cane alcohol, not gasoline.
     
    Last edited by a moderator: Mar 30, 2011
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  3. adoucette Caca Occurs Valued Senior Member

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    NOPE, let's CONTINUE with that quote shall we:

    http://www.clean-diesel.org/highway.html

    There are penalties of up to $32,500 per violation per day for non-compliance with EPA’s ULSD fuel standards, so the incentive was pretty good to meet the Dec 1 2010 deadliine.

    And so the EPA sampled the pumps and found that by the second quarter of 2010 98.8% of diesel was already ULSD and by the third quarter of 2010 it was 100%.

    Now remember this requrement is for Diesel for HIGHWAY use, and so it doesn't apply to construction equipment.

    Arthur
     
    Last edited: Mar 30, 2011
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  5. Stoniphi obscurely fossiliferous Valued Senior Member

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    OK Arthur, so without going into detail about what exactly constitutes "construction equipment" (that could be a lot of stuff) The "new, low sulfur" diesel stinks as much as the "old" diesel in my opinion. I have not noticed any discernible difference in the terrible air pollution from diesel trucks. If this is the current state, it is unacceptable to me - the smoke is black, thick and it stinks. It makes me choke when I am in my car with the windows up. It still reeks, it is totally unacceptable and I do not want more vehicles on the road burning that crap. That is not a viable alternative to me.

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    I have some suggested reading for you on that topic too, Billy. Prohibition has not, does not, and will not work. It is an attempt to repeal the law of supply and demand. There are some things that are simply too expensive to even try to do, this is one of those.
     
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  7. adoucette Caca Occurs Valued Senior Member

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    Too bad.

    The higher CAFE standards almost guarantee that we will be driving more diesel cars/trucks in the future as Diesels are more efficient than gasoline IC engines.

    http://www.environmentalleader.com/...icles-to-account-for-10-of-us-market-by-2015/

    Arthur
     
  8. Success_Machine Impossible? I can do that Registered Senior Member

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    365
    I disagree. I'd conjecture that if they spent more time on the design process they could substantially reduce the costs, and that the high cost is a result of the short business cycle driving car makers to deliver a new unoptimized vehicle to the market.

    I'd propose that they create a concept car line with a 5-year or longer design cycle, with the sole purpose of achieving the lowest possible price for the consumer, rather than any particular sales gimmick, artistic style, etc. that probably inflates the prices considerably. Even such things as an aluminum or composite frame might lighten the vehicle, possibly reducing the mass of battery needed, in turn reducing the material cost of that major component. In fact, with battery swapping stations the car owner wouldn't own the battery, and therefore the car price itself wouldn't include the cost of that component at all.

    Furthermore, I cringe whenever I hear that cars today are still made using steel. And that's a pretty easy criticism. Get into the details, and there's probably a list a mile long of design improvements that could be made. Today's cars are not optimized, they are a mishmash of features somewhat randomly attempting to appeal to the largest population.

    I admit I hadn't considered that. However, with the battery swapping scheme the service provider has every incentive to charge overnight during off-peak hours, and would probably use the slow charge due to low demand for swaps during the night. In other words, off-peak electricity prices occur simultaneously with off-peak driving.

    On the other hand, if the service provider decides it's cheaper to stockpile fewer batteries and fast-charge them, you might be right that the losses could be 10% instead of (a much lower) %. By the way, what are the typical losses during slow-recharge?

    Fortunately most people don't drive like that. Some do, but they pay for it. And I should point out that electric cars can recover alot of energy during braking. I didn't account for that.

    You made a mistake. Stationary powerplants have been known to be upwards of 60% efficient, so the first term should be 0.60. The corrected overall efficiency would be:

    0.60x0.93x0.85x0.95 = 0.45

    Again, regenerative braking might recover alot of that 0.85 loss term. And even if they don't, 0.45 is still a huge improvement over any kind of mobile, variable speed, internal combustion engine with a end-user efficiency of just 0.20, and that's pretty much what you get whether you burn gasoline, diesel, propane, natural gas, ethanol, etc, and it still doesn't account for the energy used in production (fractional distillation of petroleum, transport). The specific energy of the fuel may vary, but the engine efficiency sucks. Even hydrogen fuel cells are only 0.40 efficient for the end-user, and that's not taking into account upstream losses caused by electricity production, electrolysis, compression, etc. The way I figure, if you're using electricity anyway, why not just use batteries?

    Battery-powered cars look pretty good to me against any alternative, just the price needs to come down.

    Net energy gain? Sounds fishy to me. It's biofuel: you have to grow it (tilling, planting, fertilizing, irrigating, herbiciding, pesticiding, harvesting); crops are at the mercy of the climate; fuel crops compete with food crops and drive up prices for both (land is a finite resource). After you harvest the crop you have to process it (fermentation, distillation, drying); transport it to gas stations. I don't know what the efficiency of all those steps are, but others have tried to determine it, and I vaguely recall that the "net energy gain" idea pretty much falls flat. Ultimately though, ethanol is used in cars with internal combustion engines (poor efficiency). That pretty much kills it.

    Brazil clearly has a large domestic biomass resource, but other countries can't expect to tap into it to any great degree. That's not to say that E10 isn't a good idea.

    I don't get this argument. CO2 production and energy efficiency aren't related. They are different contexts entirely.

    Well, with battery swapping stations, we can go with pure electric cars and ditch hybrids altogether. We won't even need ethanol, although it might be a good backup fuel for stationary powerplants since it is a monofuel and turbine engines can be highly tuned for monofuels.

    Personally, I prefer nuclear, wind, etc. as a primary energy source.
     
    Last edited: Mar 31, 2011
  9. adoucette Caca Occurs Valued Senior Member

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    Why is it that somebody on the outside of a very sophisticated design/manufacturing process thinks that they could easily improve on the process?

    Cars are built in incredible volumes and yet they are the most complex objects sold to consumers and are sold in a highly feature, function, quality and price competitive manner and because the basic sedans (like the basic designs the Leaf, Prius and Volt are based on) are so highly price/feature competive the car companies are masters at building these models at the lowest price they can.
    So even before they begin to design a new car like the Volt or the Leaf, they already know how to mass produce it at the lowest possible cost, and then each of these models had a very long design cycle and then each will go through successive years of improving on that design, so no, there are no easy savings to be had in their manufacturing because companies like Toyota, GM, Nissan, Ford, Hyundai, Audi, BMW, Mercedes, Mazda, Honda, Kia etc all compete at each price point to produce the best possible car they can at that price. If anyone of them could produce the same level car for a substantially lower price they would.

    But they can't.

    It's laughable for you to "cringe" that they still use steel. Why not write a letter to Toyota and let them in on your great discovery, I'm sure they never heard of Aluminum in Tokyo.

    Arthur
     
    Last edited: Mar 31, 2011
  10. Success_Machine Impossible? I can do that Registered Senior Member

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    How could they know the cheapest way to manufacture something before they design it. They may have a recommended manufacturing scheme for any single part, but a car has many, many parts. Knowing the best combination requires a lengthy series of iterations. I don't believe they're going far enough.

    I just googled the aluminum question....

    "I would suggest that Aluminum is preferable. It is lighter than steel, which can result in a higher performance vehicle (faster acceleration, better braking, improved fuel economy). Furthermore, unlike steel, aluminum will not rust. Aluminum is also easier to recycle. Aluminum cars have a stiffer feel- giving them a sportier feel, and absorb impact about 1.5 times as well as steel, making them safer. The downside, of course, is the high cost of aluminum compared to steel."

    Source: http://wiki.answers.com/Q/Is_it_best_to_make_cars_from_Aluminum_or_Steel#ixzz1I8yFDKfY


    Aluminum won't rust = less anticorrosion measures, coatings/paint required, less often, parts last longer. Aluminum is easier to recycle = greater salvage value. Aluminum absorbs impact energy better = lighter structure = smaller engine/battery. Aluminum can be welded, heat treated, stamped, punched, bent, drilled, machined.

    So it's more expensive. Or is it? When combined with battery-electric vehicles, is it better to have a lighter more expensive structure and a smaller battery, or is it better to have a heavier less expensive structure and a larger battery?

    And that's just pitting aluminum vs. steel. What else is on that mile-long list of potential improvements?
     
  11. adoucette Caca Occurs Valued Senior Member

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    Again, these companies have perfected the efficient manufacture of automobiles, so YES, they know how to make a car as cheaply as it can be made. Indeed, manufacturing issues are part of the design process.
    And you think that overly simplistic analysis sheds ANY light on the issue?

    Give me a friggin break.

    Serious people actually work on this and the car companies have been working on integrating more and more Aluminum into their cars for about three DECADES, but it is not as simple as you apparently think.

    http://www.tms.org/pubs/journals/JOM/0108/Kelkar-0108.html

    Their conclusion (a decade ago, but still true today) was:

    http://www.motorauthority.com/blog/1032636_aluminum-use-in-cars-hits-all-time-high

    The fact is if any manufacturer could build a car with the same functionality as one of their competitors for significantly less they would do so.

    But they can't.

    Arthur
     
  12. Success_Machine Impossible? I can do that Registered Senior Member

    Messages:
    365
    Well, we're debating whether electric cars are better. So, comparing steel to aluminum is indeed too simple. We should really be comparing both those metals to lithium as well.

    Cost of cold rolled carbon steel = $ 790 / tonne (source)

    Cost of aluminum = $ 2520 / tonne (source)

    Cost of lithium metal = $661,200 / tonne (source)


    Conventional argument against using aluminum in a car with an IC engine:

    Aluminum car bodies are lighter than steel car bodies.
    Reducing weight results in better fuel economy.
    Therefore a car with an aluminum body has better fuel economy than a car with a steel body.
    Fuel costs money.
    A car with better fuel economy will consume less fuel.
    Therefore a car with an aluminum body will have lower fuel costs.
    However, aluminum is 3x the cost of steel.
    The difference in cost between the aluminum body and the steel body might be larger than the difference in fuel costs.
    Therefore the lower fuel costs of a car with an aluminum body might not be enough to offset the increased cost of the aluminum body, versus the higher fuel costs of a car with a less costly steel body.

    New argument in favor of using aluminum in an electric car:

    Aluminum car bodies are lighter than steel car bodies.
    Reducing weight results in better energy economy.
    Therefore a car with an aluminum body has better energy economy than a car with a steel body.
    Energy costs money.
    A car with better energy economy will consume less energy.
    The amount of lithium in a battery is proportional to energy consumption.
    A car with better energy economy will not require as much lithium in its batteries.
    Aluminum is 3x the cost of steel.
    Lithium is 837x the cost of steel.
    The use of Lithium is inversely proportional to the use of Aluminum.
    The more steel is replaced with aluminum, proportionally less lithium is required.
    Therefore a car with an aluminum body will have smaller lithium batteries.
    The energy cost savings of the aluminum body will be amplified by the material cost small lithium batteries.

    Overall, the combination might be a winner. Might not be enough, but it might be a step in the right direction. And I bet there's a long, long list of potential improvements to be made in cars.
     
    Last edited: Mar 31, 2011
  13. chimpkin C'mon, get happy! Registered Senior Member

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    4,416
    Along those lines-question:
    What sort of novel materials are they working on that might replace both aluminum and steel for car bodies?

    I was just wondering...I keep thinking of the way bird's bones are shaped-porous to minimize weight, but the pores are shaped such that they don't compromise strength that much...I wonder what sort of frame materials might be lighter and better at absorbing shock?

    I just know air bubbles in steel are generally considered a bad thing-they create a place where fracturing can occur over time.
     
    Last edited: Mar 31, 2011
  14. Stoniphi obscurely fossiliferous Valued Senior Member

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    3,245
    Just read an article on a new hemp/polymer composite compact car that weighs in 1200 pounds lighter than a Ford Focus. The composite is stronger and cheaper than carbon fibre composites and is biodegradable at the end of its work life. That's a replacement that works. (likely outside the US of A though)

    They are only an acceptable alternative if the exhaust is cleaned up. In its current form the cancer risks add to the cost substantially, if indirectly. There is a huge difference between a top - end European sports car at peak tune and a fully loaded semi chugging down the highway. If I can see a cloud of black smoke coming from the exhaust pipes, it ain't clean. If the stench from that smoke chokes me and makes my eyes burn it is not a viable alternative no matter how cheap it may be to run.

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  15. Fraggle Rocker Staff Member

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    The new diesel engines have been cleaned up dramatically. Apparently it's not hard; last time I checked Daimler-Benz was running ten years ahead of the legislation. The major reason diesels are such a problem is that they are used in trucks, buses, locomotives and other utility engines which are overhauled multiple times and never retired. Even diesel cars last longer than gasoline-powered cars: we still have the 1978 Mercedes 240D that we bought new and it still runs like new. A 1978 gasoline-engine car is either a beloved antique with a "Historical Vehicle" license plate, or a barely-running junkheap.

    For forecasting purposes the U.S. auto fleet is considered to completely turn over every ten years. Not so the truck and bus fleet. There are a lot of old diesel engines in operation that were not built to the new standards. Unfortunately, regardless of their health impact, the U.S. economy could not afford to replace them all. Besides, that's a fashionable new screed. When I was a kid nobody complained about diesel smoke bothering their respiratory system any more than they complained about being allergic to peanuts or cats.
     
  16. adoucette Caca Occurs Valued Senior Member

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    Again, you think the car companies COULD make the cars cheaper, but there is no indication that they can. As pointed out it is a very competive market and price is a main competiton point, so what you are suggesting makes no sense at all. You pretend that you know all these ways about how the car companies could make these cars cost significantly less, that they are simply not doing and that is absurd. Everything you have mentioned the car companies are fully aware of, it's just, as your horribly wrong figures above demonstrate, not as easy as you think.

    As far as these EVs, industry reports over the last several years have indicated that all of these new PVs and Hybrids cost up to a Billion in Development costs and the initial models cost (not including development) the companies more than they were selling them for because of the relatively low volumes they were/are making. The car companies are subsidizing the costs to get their models accepted. Once the volumes go up, the costs to the manufacturers will go down, but not to the consumer, which is why Toyota is now making a profit on thier current generation Prius.

    Arthur

    http://www.transportation.anl.gov/pdfs/TA/149.pdf
    http://lithiuminvestingnews.com/1727/lithium-prices/
    http://green.autoblog.com/2010/05/2...eaf-battery-pack-including-how-recharging-sp/
    http://www.asminternational.org/pdf/spotlights/6180_pg87-118_web.pdf
    http://gas2.org/2010/11/29/chevy-volt-cost-40000-to-build/
    http://money.cnn.com/2006/02/17/news/companies/mostadmired_fortune_toyota/index.htm
     
    Last edited: Mar 31, 2011
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    It is clear that you prefer all electric cars with many battery swap locations, which is strange as you do realize that there is a large capital cost to the swap station owning many batteries which somehow the drivers of electric cars must pay for.
    Yes. That is the tradeoff he faces: Bear the capital cost for all the slowly recharged batteries he may need to swap the next day vs. be less efficient with rapid recharge so that the first he swaps out in the AM can be given to a driver arriving at noon time for a battery swap. To tell that late in the day driver with a nearly discharged battery: “Sorry we don’t have any fully charged batteries that will fit in your car, but I can let you have one with 35% charge which probably will get you to another swap station.” will not be very attractive as user pays twice for the swap (in both time and money).

    This also makes clear that there must be several different capacity batteries, all standardized in design. I.e. the capacity needed in a small light weight car is not same as in the bigger EV station wagon. Thus there would need to be at least three different standardized battery sizes.

    To compute how many of each size the recharge station, which make 50 swaps per day on average, is a complex statistical problem. One needs to know the dispersion of demand –for example what is the probably that station will have a 100 swap demand day? Even if rapid recharge is used, to lower the capital cost, I would guess that station doing an average of 50 swaps/ day needs about 60 batteries of each of the three standard sizes to only very rarely tell the late arriving driver:”Sorry…”

    Also note a 50 swap average station is an extremely small one. The typical gasoline station must fill at least 2000 tanks a day. As the range of the typical car on a full tank is at least three times greater than an all electric cars Gasoline cars need to fill tank less than 1/3 as often as the all electric car does. Thus the typical size swap station will make about 6000 swaps per day, but be prepared for the occasional 10,000 swap day. That is a hell of a lot of battery capital the EV drivers will pay for in some way.

    To make this same point quickly in a different way: The capital cost of a gallon of gasoline at the gas station, including the cost of fuel pump and a 20 year large in ground tank, is less than $5. That gallon will provide about the same driving range as $5,000 worth of batteries will. Thus, if there is no reduction in the number of miles driven, the battery swap system requires about 1000 times more capital investment. Even if different analysis reduces that factor to 500 times more – it clearly show the battery swap system is not feasible economically. Basically it is the high capital cost per mile driven, compared to gasoline that kills the battery swap system. Not even the US can afford battery swap EVs to be more than a few percent of the car on the road.

    This fact makes a “catch 22” – If there are only a few battery swap cars, then there will be very few battery swap stations – very high probably that none is nearby when you need it. Where battery swap is economically feasible is in private fleet cars, taxis, and delivery trucks that operate from a home base. They can all have identical size batteries and the statistical variations in recharge demand at their base is very small – I.e. the ratio of batteries at the base to batteries in cars can be less than 1 to 1, not more than 3 to 1.
    I think China's new super heated steam coal fired electric plants can get 60% of the fuel energy converted into electrical energy, but very much doubt any in the US can as they operate at lower temperatures - There is no way around the Carnot conversion limit. If you can document US coal plant can, please do so. Also I think the modern fuel injected IC does better than 20% efficiency even without heat recovery from the exhaust. (That could provide the AC, etc. but does not as too much added capital cost for a heat power AC unit.)
    Sure they are very directly related if energy source for charging batteries is fossil fuel. – Cut the efficiency in half in that case doubles the CO2 release.
     
    Last edited by a moderator: Mar 31, 2011
  18. adoucette Caca Occurs Valued Senior Member

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    7,829
    I don't think so Billy.

    A large gas station does most of it's business over ~20 hours and has maybe 10 pumps but even at the best locations they aren't all going continuously and a stop for gas, which often includes checking oil, cleaning windshield, getting snacks, cigs, drinks etc probably takes at least 10 minutes on average.

    20 hours * 10 pumps = 200 pump hours * ~6 pumps per hour = 1,200 maximum tanks per day.

    At 80% pump utilization that's around 1,000 tanks per day.

    As far as how this relates to a Battery Swap station, I think there are several issues that you might want to also consider.

    One, a swap at a Battery Swap station is likely to cost quite a bit more than slow charging your battery overnight during off peak hours, so PEV users will try to hit the road in the morning with a fully charged battery and so the amount of swaps done in the morning would be very low, indeed one would expect a spike in the late afternoon, so the average utilization of one of these stations would not be spread across the day like it is for a gas station.

    Two, the automated nature of the swap requires a very much more expensive robotic operation than a simple gas pump, indeed it's a drive in building like a car wash and so it is not likely that you could have nearly as many "swap lanes" as there are pumps. This combined with the peak demand function is likey to create a line at the swap stations and a finite limit on how many cars you could service in an hour. For instance a two lane swap station could handle about 60 cars per hour tops. If you had a peak afternoon swap period that lasted 3 hours or so, the best you could handle would be about 180 cars, but adding more lanes would not likely be worth it because of the low utilization the rest of the time.

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

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    23,198
    BTW, if another nail in the battery swap coffin is needed, let me tell about my 14 year old calculator. When not in use, it sits in a sun facing window to keep battery charged. It has four small solar cells, nice big keys and display.

    All batteries have a "self-discharge" rate (different for different chemistries) which grows worse the more they are used (or just by time). The battery in that calculator will now self discharge in less than 30 minutes. The owner of a car with an old battery in it will soon know that self discharge has drained most of it capacity, if parked for 8 or so hours, so he will swap it out to be someone else's problem. The battery swap station may not know it is a "bad battery" with high self discharge rate ( certainly not when he is charging it). Thus in all innocence he will put it into your car and if you drive it to work and park it 9 hours, it may be nearly dead when you want to go home.
     
    Last edited by a moderator: Mar 31, 2011
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    23,198
    I approached the problem this simple way: 48 swaps in typical day is less range given to EV cars than 16 gasoline tank filling per day as a tank of gas will provide more than three times the driving range. I would call a station that only fills 16 gas tanks per day "extremely small"

    I do however agree 100% with the rest of your post. Having enough robots or parallel manual swap stations to keep lines less than a hour long in the late afternoon probably does cost more than 5 times the capital that I include in my calculation (only the capital cost of batteries at the station)

    Thus, I will increase from 1000 to 5000 times more capital is needed for the battery swap system (than gas station system) to include these larger costs, which I neglected. But that is not important as even if the swap system were only 100 times more capital intensive, it is not economically feasible.

    BTW, thanks for this very interesting link: http://www.sae.org/events/pfl/presentations/2009/RolandGravel.pdf
    I do however think gasoline must cost about $10/gal to make a low temperature Rankine cycle bottoming heat engine operating on the exhaust heat pay for its capital cost.
     
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  21. adoucette Caca Occurs Valued Senior Member

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    7,829
    NOPE


    http://www02.abb.com/global/seitp/seitp202.nsf/c71c66c1f02e6575c125711f004660e6/64cee3203250d1b7c12572c8003b2b48/$FILE/Energy+efficiency+in+the+power+grid.pdf

    You can't use the value for the most efficient generation as the AVERAGE efficiency of generation. A more reasonable value would be ~45%, but you also left off the ~5% losses in Transmission and Distribution, so Billy's original figures of .40 x .93 x .85 x .95 = .30 are more realistic for the real world we live in.

    And .30 is low nowadays for advanced IC engines

    http://www.sae.org/events/pfl/presentations/2009/RolandGravel.pdf

    Arthur
     
  22. adoucette Caca Occurs Valued Senior Member

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    Yes, but the discussion is about EVs and no one is suggesting that there is any chance that Semis will ever be converted to battery power. 18 Wheelers are built for long distance hauling of freight and thus aren't really the subject of this discussion.

    They are being cleaned up though because they are now burning ULSD and via EPA's SmartWay Transport program and because a cleaner burning diesel is a more cost effective diesel.

    http://www.epa.gov/smartway/transport/index.htm

    Arthur
     
  23. adoucette Caca Occurs Valued Senior Member

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    I don't think gas will need to cost nearly that much per gallon before various Thermal Generation systems are used to replace the motor driven alternator functions as we seem to use a lot of electicity when we drive and none of it is "free".

    The solutions will pay for themselves on the long haul diesels first though.

    Arthur
     

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