How much pollution does an electric car produce?

snowman · 10-30-2007, 10:44 PM

How much pollution does an electric car produce, thats total source to pollution per mile? IT IS NOT ZERO!

Data that I have indicates the overall efficiency of an electric car, source to power to the "crankshaft" is about 40%. Thats about the same as a modern diesel and only 5 to 8% worse than a modern gas engine. I mention this point because of the bogus figure often cited by electric car nuts is near 100%. That is totally bogus and not supported by any data.

My question is very important in solving our energy/pollution problems. You would think that the electric car industry would have this answer off the top of their heads. No they do not, in fact I don't beleive they even know the answer as incredible as that may sound. If they do know the answer they are keeping it a closely held secret. If so WHY?

In any case the answer is important in that it provides a baseline for an OPTIMUM pollution vehicle. Another number is needed. What level of pollution can a vehicle produce and not make any practical difference? Its NOT zero. This number is also needed. Why? how else can we determine if we have produced the ultimate vehicle? Reducing pollution further is a net waste of resources. Resources that could be solving real problems vs imagined ones.

nostatic · nostatic's Garage

i thought you liked new-que-ler power. If so, you should love electric, and would result in a very "clean" car.

Dantilla · 10-31-2007, 03:13 AM

The Tesla is still a really cool car.

hardflex · 10-31-2007, 04:49 AM

I suspect the 40% number comes from the ineffeciency of generating the power via coal or natural gas or whatever. You can't blame that on the car.

oldE · 10-31-2007, 05:22 AM

The inefficiencies are accumulative.

Yes, there are losses when you remove the energy from coal/natural gas/ oil etc to electricity. Then you have to transmit it through wires, step it up for transmission, step it down for domestic use, each transition has its own losses.

Then you store that energy in a battery of some type. Even with our friend who was promoting 'gerarators', there is no free lunch and more losses are encountered between what you put in and what you can get out. Finally you rely upon an electric motor to convert what you have left to mechanical motion.

In truth, electrics are not 'zero emissions vehicles' they are 'remote emissions vehicles'.

Les

sammyg2 · 10-31-2007, 06:28 AM

For every watt of power that is charged into a battery, you only get a fraction back out. That watt required energy to create it. That is in big part why electric powered cars and not as efficient as the tree huggers might lead you to believe.

Nuclear power is stil lthe cleanest, most efficient source but I don't want it in cars.
If they can develop a battery that is much more effcient that would be the answer.

hardflex · 10-31-2007, 06:48 AM

Hmm, this says electric motors are from 80 to 90+ percent efficient with the power they are given, compared to 30 to 40% with gasoline engines. If batteries are inefficient, maybe our cars should be like slot cars, getting their power from the road.

Still don't think you can blame the electric motor for inefficiencies and pollution of generating power with gas and coal. There is Nuclear, Hydroelectric, Solar, Wind power, all of which would make electric cars clean and non polluting.

NEMA Design B Electrical Motors

Electrical motors constructed according NEMA Design B must meet the efficiencies below:
Power
(hp) Minimum Nominal Efficiency1)
1 - 4 78.8
5 - 9 84.0
10 - 19 85.5
20 - 49 88.5
50 - 99 90.2
100 - 124 91.7
> 125 92.4

M.D. Holloway · 10-31-2007, 06:54 AM

What about the pollution produced in mining the metals used in the battery production not to mention the toxic waste for the production and disposal of the batteries?

And I agree with you, the pollution generated to produce electricy as well is something to consider.

hardflex · 10-31-2007, 06:56 AM

Slot Cars

hardflex · 10-31-2007, 07:08 AM

Gasoline and Battery Power Efficiency
The efficiency of a gasoline-powered car is surprisingly low. All of the heat that comes out as exhaust or goes into the radiator is wasted energy. The engine also uses a lot of energy turning the various pumps, fans and generators that keep it going. So the overall efficiency of an automotive gas engine is about 20 percent. That is, only about 20 percent of the thermal-energy content of the gasoline is converted into mechanical work.

A battery-powered electric car has a fairly high efficiency. The battery is about 90-percent efficient (most batteries generate some heat, or require heating), and the electric motor/inverter is about 80-percent efficient. This gives an overall efficiency of about 72 percent.

But that is not the whole story. The electricity used to power the car had to be generated somewhere. If it was generated at a power plant that used a combustion process (rather than nuclear, hydroelectric, solar or wind), then only about 40 percent of the fuel required by the power plant was converted into electricity. The process of charging the car requires the conversion of alternating current (AC) power to direct current (DC) power. This process has an efficiency of about 90 percent.

So, if we look at the whole cycle, the efficiency of an electric car is 72 percent for the car, 40 percent for the power plant and 90 percent for charging the car. That gives an overall efficiency of 26 percent. The overall efficiency varies considerably depending on what sort of power plant is used. If the electricity for the car is generated by a hydroelectric plant for instance, then it is basically free (we didn't burn any fuel to generate it), and the efficiency of the electric car is about 65 percent.

lendaddy · 10-31-2007, 07:45 AM

Quote:

Originally Posted by hardflex

Slot Cars

hardflex · 08:34 AM

slot cars

Shaun @ Tru6 · 10-31-2007, 08:34 AM

Quote:

Originally Posted by hardflex

slot cars

http://en.wikipedia.org/wiki/Image:Tr%C3%A5dbuss_Landskrona.JPG

http://en.wikipedia.org/wiki/Image:Trolleybus4120.Harvard.agr.JPG

I was on the 71 (Watertown Square to Harvard Square) yesterday going into the Red Sox parade. the only downside to these are the unsightly grid of wires running over the streets.

lendaddy · 10-31-2007, 08:38 AM

Yes, running wires over our highways is quite logical.

"Johnson, you keep feeding me worthless ideas"

"Can do sir"

hardflex · 10-31-2007, 08:51 AM

Amazing that on a car forum where every tweek of a camshaft is pondered for it's performance potential, you can dismiss out of hand a 300%+ improvement in efficiency just because it's a little different. Oh well, carry on.

lendaddy · 10-31-2007, 08:57 AM

No man it was a brilliant idea, don't take me wrong.

sammyg2 · 10-31-2007, 09:13 AM

Quote:

For every watt of power that is charged into a battery, you only get a fraction back out. That watt required energy to create it. That is in big part why electric powered cars and not as efficient as the tree huggers might lead you to believe.

Case in point, the statement in the above post. Batteries are 90% efficient? At first I thought that was BS, but it's on the internet so it must be true

They are probably talking about how much energy is actually stored vs. released, not how much energy it takes to charge the batteries vs. how much is relleased.

legion · 10-31-2007, 09:16 AM

I think the fundamental problem with electric cars is this:

How long would it take an electric car to drive from New York to LA?

Think about it...

hardflex · 10-31-2007, 09:19 AM

how long does it take an electric train to get from Paris to S. France?

hardflex · 10-31-2007, 09:40 AM

Sammy, a quick google search shows a 70% efficiency in charging Lead Acid Batteries. 70%x65% is still more than twice as efficient as internal combustion.