Are electric cars actually energy efficient?

Question

The power comes from a power plant producing electric power that looses about 75% of the energy in the fuel when converting to electric power that goes to your house. There is another efficiency loss when charging the batteries. There is another efficiency loss in the motor.

It seems to me although the electric cars are great in reducing pollution in the city, they may produce more pollution overall. What do you think? I do know from physics you can't create energy from nothing. Am I missing something?

Answer 1

Because of the efficiency of electric engines, plug-in hybrids and electric cars produce far less greenhouse gas emissions than internal combustion engines even if the electric grid is powered mostly by fossil fuels like burning coal. Here are some numbers.

PHEV = plug-in electric hybrid vehicle
HEV = hybrid electric vehicle (like the Prius)
EV = electric vehicle
ICE = internal combustion engine

"PHEVs reduce CO2 emissions by 37%-67% compared with ICEs and by 19%-54% compared with HEVs in well-to-wheels (W2W) analyses assuming fueling with gasoline and electricity from the U.S. mix of power plants (and ignoring one or two outliers in the data). PHEVs reduce all other greenhouse gas emissions too.

EVs reduce CO2 by 11%-100% compared with ICEs and by 24%-54% compared with HEVs, and significantly reduce all other greenhouse gas emissions, using the U.S. grid
mix. If all U.S. cars were EVs, we’d reduce global warming emissions. Using electricity strictly from coal, EVs still would reduce CO2 by 0%-59% compared with ICEs (one analysis found 0% change; six others found reductions of 17%-59%) and might produce 30%-49% more CO2 than HEVs (based on only two analyses). On the other hand, if electricity comes from solar or wind power, EVs eliminate all emissions. Using natural gas to make electricity, emissions fall in between those from coal and renewable power."

Answer 2

An electric car, using today's technology is more efficient than an internal combustion car. I think about 60% of the energy produced by gas is lost in the form of heat.

There is even more of an energy loss if you take into consideration all aspects of an internal combustion car. There is an energy loss in the form of evaporation at the gas pump. The loss is greater in the summer time than in the winter. Automatic transmissions waste more energy than a manual transmission. Look into the loss of power in the torque converter.

As far as the power plant goes, converting oil into gas/diesel uses energy also. Refineries have stacks that release pollutants into the air as well. Refineries also get a bill from the power company. So, some of that power plant smoke that you are attributing to electric cars is actually going toward refining oil into gas. Even if the gas/diesel is piped directly to the local gas station, the pumps pushing it will need energy to run. Since the majority of gas stations receive their fuel via truck delivery, the use of fuel for that can be added to the 'loss' column. Then there is the evaporation of the fuel while filling the delivery truck and also when that truck delivers its load to the gas station.

All gas has to be processed through a refinery, but not all electricity is produced from coal. Where wind, solar, and water is used to produce electricity, electric cars beats the interal combustion car. When nuclear power is used, the environment takes less of hit as well.

Are you missing something? Yes! All your data on the INefficiency of internal combustion cars.

Answer 3

A high efficiency electric motor can deliver efficiencies in excess of 90% (axial flux motors used in solar car racing are as high as 98%). They also have the ability to regenerate power during breaking and descending hills.Electric motors are more efficient over a wider range of engine speeds.

Most of the efficiency gains from the petroleum used in hybrids comes from ensuring that the internal combustion engine is fully loaded whilst running, and recharging during braking .

The energy used by any vehicle is a function of wind resistance rolling resistance and energy efficiency.

Energy produced from an internal combustion engine can have similar efficency as electric energy generated at a power station, only when loaded correctly. A staionary petroleum vehicle uses energy to idle. (zero efficiency.)

Most of the energy is lost as heat in both. There are losses involved in delivering both forms of fuel to a vehicle. Again these are similar.

One large generator as can be run far more efficiently than 1000's of small ones.

In summary
A battery electric car is about as environmentally friendly as a hybrid car if charged solely from coal fired power. (zero from green sources.)

edit
I should clarify here. Using the latest technology. An old style brushed dc motor with lead acid batteries is not going to be anywhere near this good.

Still not nearly as environmentally friendly as riding a bicycle or walking, but better.

Answer 4

Electric car reduce pollution at the location of the car being operated.

Whatever mode of electric power generation is used determines the actuall amount of pollution created to provide the car's power.

There's inherant losses in electric power generation and converting that to the chemical energy in a battery and then again when converting that to electrical power to drive the vehicle... So its not going to be a very efficient vehicle overall.

Answer 5

They're not perfect by any means but they're getting better,
probably the best way to deal with it is to have a solar powered
charging station, that way you eliminate two entire parts of that equation, first the generating part then the charging part because even though you may have a charging loss it's free so it doesn't really effect anything.

Answer 6

The idea is that the cars are part of a sytem including alternative energy; nuclear, solar, wind. Then they will provide a way to power cars without using fossil fuels and causing global warming.

Answer 7

Come on . . . use a little logic here. They have to be efficient because you can't drive them very far before they become unplugged. Plus, even if they made, like, mile long extension cords, they would be a hassle to use.

Answer 8

If you need a car to help you feel masculine, than it is you that are effeminate, not the automobiles.

Answer 9

yes electric cars are more effecient than petrol or diesal cars
as they are ment computerised they are programmed to give the best results

Answer 10

"I do know from physics you can't create energy from nothing"
well, big bang was created from nothing. lol