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Why Electric Cars are Really Coal Cars

By Professor Chris Rhodes | Tue, 05 April 2011 10:58 | 17

I saw a wonderful play at the Royal Court Theatre in London recently: "The Heretic" by Richard Bean. In a nutshell, the plot centres on a female academic, Dr Diane Cassell, who is researching sea-level rise. She finds none at some measurement point in the Maldives, but realises that both land and sea are rising together. Thus, while sea-levels are indeed rising, the islanders are unlikely to be forced from their lands by them. If she publishes her results, the department stands to lose a very lucrative contract from an insurance company and so her Head of Department forbids her to go public which she does, and on national television at that, so getting fired from her job. The Human Resources person is grimly hilarious.

In the play, one of her students with utterly green credentials including eating lots of garlic to apparently curb his own bodily greenhouse-gas emissions, refuses to go on a field trip in the university minibus on the grounds that it runs on fossil fuels, preferring instead to cycle forty miles there and forty miles back.

Diane asks him: "In your green future, how would we get fourteen students fifty miles to the North Yorkshire Weather Station?"
He replies: "There should be like an electric car/minibus. Electric cars don't have any emissions."
Diane responds: "Electric cars should be called coal cars. 30% of our energy comes from coal. Electricity is not naturally occurring in nature."

Now this does raise an issue about the "cleanliness" of electricity, which is all the more salient in view of the U.K. government's aim to install thousands of electric charging points around the country for electric cars with the aim to "wean us off imported oil". However, the majority of electricity in the U.K. is generated using power stations fired by coal (28%) and gas (45%), and hence even if a substantial substitution of the present 30 million British oil-fuelled cars by electric vehicles could be made, it would entail the consumption of vast quantities of these other fossil fuels instead to provide the additional electricity for them.

It is claimed in a Royal Academy of Engineering (RAE) report on electric cars that they are in any case cleaner because 80 - 90% of the energy put into them in terms of electricity is recovered in terms of useful power at the wheels, to be compared with 20 - 30% in a conventional oil-powered car. Well, that sounds good, but the reality is that only about one third of the energy in the coal or gas actually ends-up as electricity because of the Second Law of Thermodynamics and the Carnot Cycle limit - the other two thirds being thrown away as heat. Thus the electric car is harvesting in terms of well-to-wheel miles only about 27% of the original fossil fuel energy, so not that much better than the standard car running on petrol or diesel. The difference is merely whether about the same quantity of waste heat energy is thrown away at source or in the vehicle.

The green energy company, Ecotricity refers to electric cars as "wind-cars", to stress that they could run on electricity made from green sources such as wind. Indeed, the U.K. has made the decision to focus on wind-energy to meet its carbon-emissions targets, and plans to build offshore wind-farms on an impressive scale to do the job. It is advised by the Committee on Climate Change that by 2020, 1.7 million electric cars should be on Britain's roads, or just over 5%, which I don't honestly see would make a serious hole in our demand for imported crude oil.

To decarbonize the national grid would require another 30 - 40 GW of green generating power, or "the equivalent of a hundred large offshore wind-farms," according to the chief economist of the CCC. These would need to be large indeed. Assuming a rated capacity per turbine of 5 MW, and a capacity factor (actual output) of 30%, we have 1.5 MW for each. Thus we need around 20,000 - 27,000 turbines to produce 30 - 40 GW of power. So that means 100 wind-farms with 200 - 270 turbines each. If one turbine per day were manufactured, no mean feat given present manufacturing capacity, the process would take 55 - 74 years to complete, with the installation of them as a separate effort. As noted in previous posts, there is the further question of whether there will be sufficient quantities of rare earth elements (REEs) available on the world markets to make the turbine magnets which need about one tonne of neodymium per 4 MW of rated capacity.

Clearly, we have a serious problem in switching from dirty oil cars to green electric cars, which will need to be built themselves. There are many issues of the materials needed per se, and a hybrid car e.g. a Prius needs 1 kg of praseodymium for its motor plus 15 kg of Lanthanum for its battery, while a fully electric vehicle will require much more of each. Personal electric cars are still a far better option than personal hydrogen cars for all kinds of reasons, but if governments are serious about introducing electric transportation in place of oil, the creation of electrified mass passenger transport, e.g. trains and trams would be the better way to go.

By. Professor Chris Rhodes

Professor Chris Rhodes is a writer and researcher. He studied chemistry at Sussex University, earning both a B.Sc and a Doctoral degree (D.Phil.); rising to become the youngest professor of physical chemistry in the U.K. at the age of 34.
A prolific author, Chris has published more than 400 research and popular science articles (some in national newspapers: The Independent and The Daily Telegraph)
He has recently published his first novel, "University Shambles" was published in April 2009 (Melrose Books).
http://universityshambles.com

About the author

More recent articles by Professor Chris Rhodes

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What Happens When the Oil Runs Out?
Tue 19 February 2013
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Sun 10 February 2013
The Petroleum Rollercoaster
Sun 27 January 2013
Why EROEI Means Mining in Space will Never Work
Thu 24 January 2013
Low Energy Light Bulbs Not So "Green" After All?

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  • Anonymous on April 05 2011 said:
    A possible alternative to electric vehicles is spark-ignited internal combustion engine vehicles fueled with compressed natural gas instead of gasoline. In the wake of the Fukushima disaster and also, in the wake of greatly increased production of natural gas from "fracking", we will invariably see natural gas fired gas turbines generating more of our electricity here in the USA. So in effect, electric cars would become natural gas-fueled. We need to ask what is better in terms of well-to-wheels efficiency: EV's or CNG-fueled vehicles.Re windmills: My biggest fear is that if we build enough of them to replace both coal and nuclear power plants, mother nature will sooner or later think of a showstopper issue to throw in our faces. I believe we should build more nuclear power plants, with of course improved safeguards.
  • Anonymous on April 06 2011 said:
    Verey interesting article, but we have a problem. The Dean of Engineering at Illinois Institute of Technology (in Chicago) expelled me from school, calling me hopeless, but 7 years later, after almost three years in the infantry, I was designing terminal installations for US Navy sonar and radar.That was possible in engineering because THEY know how to teach engineering. THEY don't know how to teach energy economics. Everybody who has looked at the first chapter in my new energy economics textbook tells me that it is lovely, and this and that, but I am not certain that it suffices. There are some excellent contributors to this and other forums, but I constantly encounter opinions about energy from well educated economists and engineers and journalists that are strictly off-the-wall.And perhaps worst of all are arcane contributions to so-called learned journals.
  • Anonymous on April 06 2011 said:
    "a Prius needs 1 kg of praseodymium for its motor plus 15 kg of Lanthanum for its battery, while a fully electric vehicle will require much more of each."Sorry Prof, but that is dead wrong. Fully electric cars use AC induction motors and lithium batteries, while the Prius uses a permanent magnet motor and Nimh batteries.Hence, the full electric doesn't need the praseodymium or the Lanthanum.You should endeavor for greater accuracy.
  • Anonymous on April 06 2011 said:
    BBTOM:The original Prius design (1997) and the revised design circa 2005, used electric machines (motor/generators) with powerful permanent magnets requiring neodymium. Some of the more recent electric vehicles we are seeing, like the Tesla, use induction motors which have no permanent magnets, and ergo: no rare earth metals. Here's a question for the electrical engineering folks: Are permanent magnet motor/generators being replaced by induction machines only because rare earth metals like neodymimum have become too costly? How much will the performance of future Prius and other electric and hybrid electric vehicles suffer, owing to unavailability of rare earth metals?
  • Anonymous on April 06 2011 said:
    In addition to the errors pointed out about rare earth metals, the whole primise of this article is wrong.http://www.decc.gov.uk/en/content/cms/statistics/fuel_mix/fuel_mix.aspxThe DECC figures for last year's energy generation emissions show that 410g were emitted for each kWh produced in the UK. 10% is lost to transmission and a futher 10% to charging the cars.EV consumption is typically between 125Wh/km at town speeds and 190Wh/km at motorway speed (e.g. 70mph).Thus, even a high performance EV travelling at motorway speed is emitting 94g/km at the power station. Equivalent figures for ICE cars are derived from the NEDC tests which are at much lower average speeds.The entire "long tailpipe" argument is a red herring beloved of EV detractors. It's pretty easy to prove wrong with some trival mathmatics and I'm surprised a professor would put their name to it.
  • Anonymous on April 06 2011 said:
    The professor does indeed make many simple errors.One I'd like to highlight is the assumption that EVs would primarily be using electricity from coal fired power stations - why assume that? On his own figures gas fired power stations provide 50% more of the UK's electricity than coal does. And of course it is much cleaner and it has a far higher thermal efficiency (than coal).(cont..)
  • Anonymous on April 06 2011 said:
    (cont from previous due to character limit) Choosing coal because it is the dirtiest and least efficient way to make electricity, at grid scale - makes no sense other than to support an otherwise unsupportable argument.In any serious analysis of the carbon footprint of EV's the starting place would be the UK's average grid composition. Further analysis would highlight a 'time of day issue' - the majority of EVs are and will be charged overnight, when the load factor of the grid is at it's lowest and when Nuclear power dominates the mix. There's little or no coal burnt in the off peak times - the times when EVs typically charge up.Cheers.
  • Anonymous on April 06 2011 said:
    Another problem with this article is that there is a huge assumption that electricity CAN'T get cleaner. An internal combustion engine designed to run gasoline will ALWAYS burn gasoline, however an electric car may get it's power from 30% coal today and 5% coal in 12 months...
  • Anonymous on April 06 2011 said:
    Alex:The new "pure" electric vehicles use rare-earth-free Li-ion batteries because nickel-metal-hydride batteries don't have the energy storage density to provide a practical range.These EVs generally use induction motors without any permanent magnets because with electronic control, it is possible to vary the magnetic field strength of the rotor, which effectively changes the "gear", eliminating the need for a mechanical transmission. A parallel hybrid like the Prius requires a complex transmission anyway to combine the motor and engine contributions to the wheels.Induction motors are substantially less expensive, but bigger and heavier, than permanent magnet motors of the same power rating.
  • Anonymous on April 07 2011 said:
    Whenever I read an article like this, I wonder "who got paid how much and by whom?" So many articles about electric cars are sponsored by companies/organisations that have a vested interest in their failure - and in many cases it's not too difficult to guess who paid for such misinformation. Many of us are too savvy to accept all these biased articles. This one does no credit to the professor, who should stick to his new vocation of writing novels.
  • Anonymous on April 07 2011 said:
    "Electricity is not naturally occurring in nature."Uh, ok, then who do I call to shut off the electrical storm that rolled through here and kept me awake all night?
  • Anonymous on April 07 2011 said:
    Well written. I never cease to be amazed at the unwillingness/ability of most of the electric vehicle crowd to consider a most rudimentary economic analysis. Particularly if it could challenge what they know to be true. If individual business owners made decisions in this way they would soon be out of business. Regards, Martinwww.selling-a-business-without-stress.com
  • Anonymous on April 07 2011 said:
    [quote name="Curt"]Alex:The new "pure" electric vehicles use rare-earth-free Li-ion batteries because nickel-metal-hydride batteries don't have the energy storage density to provide a practical range.[/quote]Really? Then how do you explain the 150 mile range of the GM EV-1? NiMH is a practical energy source. It's been proven in millions of miles of driving in various vehicles from the EV-1 to RAV4, Insight and so on. Ni is cheaper and more readily available, less toxic and easily recyclable. If it weren't for Chevron holding large format NiMH pattens hostage they would be in widespread use today.
  • Anonymous on April 11 2011 said:
    I've read elsewhere that most energy generating facilities, including those burning coal and natural gas, are not able to power down significantly during the overnight hours when demand is lower. Since EVs would typically be carged during the overnight hours, they would be utilising energy that otherwise would not find buyers and can not be stored using curent technology.
  • Anonymous on May 08 2011 said:
    I understand electric vehicles are able to use the power from braking. By how much would this improve the efficiency of the electric vehicle compared to that of the gasoline powered vehicle? Is it significant, particularly for city driving?
  • Anonymous on June 22 2011 said:
    a special rail vehicle hauled by a steam locomotive containing the locomotive's fuel (wood, coal, or oil) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, so tenders are necessary to keep the locomotive running over long distances.
  • Dr H Fraser on November 26 2012 said:
    The green energy lobby is enormously powerful, like the tobacco lobby in the 1960s, the anti-global warming lobby in the Bush administration. And their main target is to argue against nuclear energy as the most efficient carbon-free source of energy.
    The "cost" (being added to the fuel bills of all householders)is equivalent to units of energy; the energy yields from, say wind, are, variously, 3 - 22 times less than the energy inputs for the building, distribution, maintenance etc. But landowners receive £25k/turbine/year.
    This anti-nuclear conspiracy has to end, or is it too late.
    H Fraser

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