Posted on 12/11/2010 3:38:13 PM PST by editor-surveyor
Vlado Bevc
Synergy Research Institute, P.O.Box 561, San Ramon, California 94583
The promotion of General Motors Chevy Volt by three mayors (Contra Costa Times, November 6, 1010) merits some mundane evaluation from the energy standpoint. Electric vehicles –with an internal combustion engine assist – are compared to a “typical car” using 13 cents of $3.00/gallon gasoline per mile, that is one that makes 23 miles per gallon. (13/300 = 0.0433 gallon/mile)
In a conventional car 25 percent of 37 kWh from a gallon of gasoline gets into traction (because of losses in the engine and drive train). “Conventional car” thus uses 0.4 kWh/mile and so does any comparable car.
Reader Coughlan (CCT, November 13, 2010) correctly pointed out that at residential electric rates of 40 cents/kWh the energy cost is “about 10 cents/mile” rather than 3 cents/mile (above calculation shows 16 cents/mile). Moreover, Chevy Volt has a 435-pound battery costing $8,000 which wears out after 100,000 miles. That adds 8 cents to the energy associated operating cost of the electric car.
PG&E also has an experimental tariff designed for users of electric cars through which all of us are subsidizing electric vehicle owners.
Electric power plants supplying energy require from 3.5 to 4 kWh of thermal energy to generate 1 kWh or electrical energy. Thus the 0.4 kWh used by the electric car requires 1.6 kWh to generate. Energy wise we are at the same place as with an internal combustion engine.
About 70 % of electric power generating plants America use coal. At heating value of 3 kWh/lb, 1.3 pounds of coal is needed to generate 1 kWh. As coal is 80% carbon 3 pounds of carbon dioxide is emitted in generating 1 kWh of electric energy. In other words, electric vehicles cause production of 1.25 pounds of carbon dioxide per mile. On the other hand, an equivalent conventional car using 0.0433 gallon/mile emits 0.78 pounds of carbon dioxide per mile. Electric cars thus cannot reduce emissions of carbon dioxide to which climate changes are wrongly attributed.
The mayors say 500,000 electric vehicles in the Bay area would reduce costs and emissions dramatically. As shown no cost reduction can happen. Moreover, if 500,000 electric vehicles using 500 gallon/year producing 4 tons of carbon dioxide each were eliminated, there would be 2 megatons of carbon dioxide emissions less. This would be only 0.4 percent of the annual fluctuation (48,000 megaton) of carbon dioxide in the atmosphere which totals about 3 million megatons, an insignificant amount.
Particularly unreasonable is the hint that electric vehicles while parked in employee parking lots could be running their gasoline engines to feed energy it back to the network. Efficiency of any electrical generator is proportional to the fourth power of its dimensions, hence a number of small power generating stations would waste more energy than a normally sized electric power plant.
Vlado Bevc
925 683 9254
As a means of providing energy from an on-board source to the wheels or any of a number of non-propulsion amenities on a moving vehicle, the use of electricity is hard to beat. It is the SOURCE of the energy that is the problem.
Generation of power from fuel cells, by the conversion of hydrogen into electrical energy, runs into a couple of problems right away, where is the hydrogen coming from, and how do we carry a sufficient supply on board for a reasonable radius of travel distances?
Regardless of how dangerous gasoline is as a fuel, at least the technology for its distribution and dispensing have been worked out over the past century or so, to the point of relatively few instances where it causes uncontrolled flame spread. So we shall have some version of the internal combustion engine as a compact and relatively lightweight power source for some time to come. The fuel may change, but the pronciples remain much the same. There may be fuels with higher energy densities than gasoline, such as Diesel fuel, requiring a more compact on-board storage tank, but most of the alternatives offered, like compressed natural gas, propane, or ethyl alcohol, have a much lower energy density than gasoline or Diesel fuel per pound, or volume, or any other measure.
Battery technology, despite a couple of hundred years of trying to find a means to pack higher energy densities into smaller and smaller space, has not yielded the reliability and means of quick refueling that liquid fuels have provided. Seems like the materials used just do not respond well to some of the thermodynamics that come into play. Rapid transfer of electrical energy almost always results in steep increases of heat output, resulting in a molten puddle of whatever materials the batteries were constructed of.
Now, if we just had superconductors that would transmit a stream of electrons at ambient temperatures, perhaps we could find a way around this bottleneck. But alas, like the promise of nuclear fusion, this always seems to be some 30 years in the future.
Except we have had several “30 yearses” in succession already, and seem no closer to the resolution of the problems.
Meanwhile, this constant tinkering with batteries as a storage medium of energy does not seem to be moving the problem. As an alternative, could one suggest the development of a compressed gas over a hydraulic fluid medium. The power plant builds up pressure in the system by compressing the gas over the hydraulic fluid, and the hydraulic fluid is piped to the propulsion wheels, which are turned by a slave hydrostatic pump. By reversing the valving, the hydrostatic motor could be turned into a pump to provide vehicle braking, building the pressure back up, which is stored in a reservoir. No mechanical drive line in involved, no gears, universal joints, or shafts anywhere.
Very large mine trucks already use a similar driveline, and it has had a number of applications in relatively low-speed, heavy-duty off-road machinery. This could be refined into a much higher-speed application, suitable for conventional road travel, with relatively few tweaks.
Is it more or less expensive than this really weird engineering that is now being put into various hybrid or full-electric vehicles? Can it be done on a practical scale?
This is what the PG&E SmartMeter™ program is about. Having the necessary amperage for charging the batteries on the cars and reducing the amount used for homes.
We need to get out of the UN as fast as possible.
Promises are best bought cheap.
The early episodes of this strip were adapted pretty faithfully in the first Buster Crabbe-starring serial, with its spark-sputtering spaceships and with Flash condemned to shoveling uranium into an atomic furnace (I always loved that part).
Like the author, I always loved that scene, too.
several years ago the army built several Hybrid Humvees. they had a turbo 3.0 Diesel instead of 6.5 and higher performance and claimed 35% increase in fuel economy. They would also go 20 mi on battery alone.
I tried to get more specs on them as to motors and batteries with out success. As far as I know no production models were ever built. Mercedes builds Hybrid farm tractors and
electric Motors are used on implements instead of PTO
Powerline losses aside, just look at the drops in both battery & electric motor power output/draw due mainly to increased resistances in cold conditions.
We’ll even ignore the large driving-capacity power losses involved in using a heater, headlights, and wipers...
With the various increased loads & losses from cold weather, what happens to range/milage, or whatever measure they use, when the thing sits in a sub-zero parking lot for 8+ hours, then must be driven home in the snowy, sleety dark?
First of all, most businesses will not allow freeloaders to charge their cars in the parking lot. Not only employees can do it, but also any member of the public. And businesses pay pretty penny for electricity.
But there is another interesting aspect. If a business provides some free (or nearly free) service to the employee then IRS will want to know more about it, since it's an unreported, untaxed compensation. No business will be willing to put its neck under the IRS's axe just to please a few employees.
So in the end there will be chargers with meters, and you need to swipe your access card to get it started, and the cost of the energy will be deducted from your paycheck.
As more and more EVs show up on the roads, energy companies will be able to take control of the situation and raise the prices to the market levels. This means that many owners of those cars will not be able to afford charging of their vehicles! The market price is not the price which everyone can afford; it's the price that results in maximum profit.
Today PG&E indeed has a rate schedule for EVs. It is time-dependent, and it can change at any time. We can't be sure that the price of gas will always be $3.20 or whatever it is today, but similarly we have no reason to believe that electric energy will be always sold for $0.10/kWh at the lowest tier.
Thanks for the ping.
I love when sane folks deconstruct the myths.
Had electric heat years back. Cost an arm and a leg!
Huh. I thought the Volt has regenerative braking. Is that not so? Any links?
‘Chevy Volt has a 435-pound battery costing $8,000 which wears out after 100,000 miles.’
I remember when Insinkerator came out with their residential model. It cost about $250.00. Not much difference than to days price, but the average hourly wadge was $.55 per hour.
“At heating value of 3 kWh/lb, 1.3 pounds of coal is needed to generate 1 kWh. As coal is 80% carbon 3 pounds of carbon dioxide is emitted in generating 1 kWh of electric energy. “
Can someone please explain to me how 1.3 pounds of coal produces 3 pounds of carbon dioxide.......It just doesn’t sound right....
short, simplistic answer that ignores impurities, and other variables; ignores (most) dismal points in calculations; and and just keeps it simple:
coal = carbon
CO^2 = 1 carbon plus 2 atmospheric oxygen atoms
C= atomic wt 12; O= atomic wt 8; O^2= atomic wt 16
CO^2 atomic wt= 12 + 16 = 28, or 2 1/3 X Carbon alone
2.33 X 1.3 pounds coal = 3 pounds CO^2
The only chance that Electric Cars might be feasible is the availability of cheap plentiful nuclear generated power. As of now electric cars run on coal.
The ‘article’ is full of false and misleading statements. Two thumbs down.
“Electric power plants supplying energy require from 3.5 to 4 kWh of thermal energy to generate 1 kWh or electrical energy. “
False. Coal plants are about 2.5:1, gas plants are about 1.7:1
“Reader Coughlan (CCT, November 13, 2010) correctly pointed out that at residential electric rates of 40 cents/kWh “
PGE top tier rates in the Bay area are about 30 cents per kwh. If yo go to smart meters and off-peak (it could be MUCH less).
“About 70 % of electric power generating plants America use coal.”
But coal is less than 45% of the electricity production. I think the Bay area is mostly nuclear and gas.
Probably the reason no one but this kook brings it up.
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