Electric cars are more fuel efficient than what?

Electric and hybrid cars are going to reduce pollution and our dependence on fossil fuels. I don’t get it.

If I recharge the electric car batteries at home, and my household current is supplied by a coal burning plant. How exactly am I contributing to a reduction of pollution, smog, and dependence on fossil fuels?

Oops. Sorry for the punctuation above…

With hybrid cars, the motion of the car (particularly during braking) regarges the battery. You never “charge it up” at home. In effect, you are capturing the energy wasted during the braking process and other engine activity.

A friend of mine has the Toyota hybrid (Prius, I think?) and she says she routinely gets 50-70mph and once she got 90mph (downhill most of the way or something).

For both, you typically get regenerative braking. When slowing down instead of converting excess energy to waste heat you use it to recharge your batteries. The 2004 Prius gets a combined EPA milage of 55 MPG, cetaianly this uses less fossil fuels than most cars.

For pure electric you get economies of scale. One can make a 50MW plant more energy efficient than a 5MW plant.

Also, not all electricity is generated by fossil fuels.


Also, the local effects can be dramatic–say, converting all of the gas-guzzlers in Mexico City, Los Angeles, and New York City to electric, hybrid, hydrogen, CNG, etc., would greatly improve local air quality, which is often hazardous for humans to breathe.

In short, cars are not that efficient when it comes to energy use and pollution output. With Hybrids, you actually scavenge some energy and return it to the system (electric batteries) and with pue electrics, you place a centralized control on pollution.

By controlling pollution output, you can help reduce the greenhouse affect…reduce ozone in big cities. If it’s centralized at all the power plants, it’s easier to manage. That’s the all-eclectric advantage.

By scavenging some energy like Hybrids do, you can get to use the electric motor when in low speed traffic - stuck around town - and really extend the overall efficiency while simultaneously not contributing to a big ol’ cloud of pollution in one spot, during the worst part of the day in some of the most susceptible areas.

Yup, as I understand it localised air quality is the major gain with electric cars, with or without regenerative braking. I no longer work for them, but until a couple of years ago I used to work for one of the oil majors with a reasonable commitment to renewable energy.

From that I saw some analysis suggesting that if you looked at the total energy and resources used to build, maintain, fuel and run the car then electric cars were a dead end. The lead in the batteries and the energy need the OP identified for recharging almost outweighed the benefits. Even more so if you factored in the resources used to find the energy (coal or gas).

As I understand it the way to go is hydrogen energy, once the problems of hydrogen fuel cell storage and easy refuelling are fixed the positive environmental benefits are overwhelming. Hydrogen when burned produces only water, and hydrogen separation can become in the future a more energy efficient process than seeking, developing and transporting fossil fuels, burning them either directly or after building electrical power generation and distribution systems etc. etc.

Also note that when you are sitting at a stop light in a conventional car you are getting zero MPG and burning gas.
In an electric or Prius (not sure about Honda) when you stop the gas engine isn’t running. The eletricity consumed is pretty small (the radio, lights, computer etc)

Note that you don’t need to use lead-acid batteries (The Prius uses NiMH)


Also, generally speaking, electric and hybrid cars are designed to be more energy efficient that your average car (or SUV). High pressure tires, low drag cooefficients and other design choices make them use less energy (and would be a benefit whether they were gas powered or electric).

The Prius uses less fuel in the “city” test than in the “highway” test, precisely for the reasons N9IWP mentioned. And the '04 model is damn good lookng too (not that I hated the previous ones).

Absolutely not. There ain’t no such thing as a free lunch. You need to put in just as much energy to get the hydrogen as you take from it when you burn it. Which means that you still need to seek, develop, and transport fossil fuels, or uranium, or whatever you’re using for your energy source. Hydrogen is not a source of energy, just a way to store it.

  • Yea, but in most countries, most if it is, and will be for quite a while. Anthracite can deluge you with numbers if you PM.

Also, the problem with saying that one thing is “more efficient” than another usually ignores the associated costs (and pollutions) of production: If car A emits one-tenth of the pollution of car B, but manufacturing car A produces ten times as many pollutants as car B, which is really better for the environment? -And, suppose that car A has a certain major part that needs replacement every couple years…?

The biggest factor that people overlook when talking about new-fangled low emission vehicles is that you’re changing where the source of pollution is. If every car were electric, it would be much easier to reduce pollution overall because the pollution would be coming just from the power plants creating the electricity. It is much easier and efficient to reduce pollution at 1000 power plants that don’t move than to have millions of cars all over the place spewing out CO2, NOx, etc.