Energy

[David S]

In my opinion the main stopper for electric cars is the limited range that can be achieved with existing battery technology. As you say it might be about 60 miles. For gasoline powered cars its more like 300 to 400 miles. Its also much quicker to gas up than to recharge the batteries.

This has been the problem with electric cars for 100 years. Figure out the answer to that and I'll make us both rich and famous.

[David S]

Electric power is needed, but the critical hurdle is energy density. This measures how much useable energy is stored in a given volume, like mass density measures the mass in a given volume. Conventional rechargeable batteries can't match gasoline and that limits batteries from competing with the internal combustion engine.

Work on the hydrogen fuel cell is much more promising. Hydrogen provides greater energy density then petroleum, and the fuel cell has been around for a long time now. It has been used in military and space applications. The biggest commercial hurdle is how to store roughly 10 kg of hydrogen in a car so that it has a range of 500 km, like a gas-powered vehicle. This is an active area of current research, and when solved can lead to a wholesale replacement of gas engines as we know them today.

Muon I have a question that possibly you can answer. Where do you get the hydrogen from? I know of two ways, both of which have problems. You can get it from water through electroysis or extract it from hydrocarbon fuels like oil or methane.

To get it from water you must put in more energy that you will get out so that will  create a huge electricity demand. Most of our electricity comes from coal burning plants which produce mostly CO2 as a product of combustion. This could eliminate our need for foreign oil but would still leave us with the greenhouse gas problem (assumming it is a problem).

If we get it from oil we are still dependent on oil. Also oil contains much more carbon by weight than hydrogen, so what happens to the carbon?

[David S]

Electric power is needed, but the critical hurdle is energy density. This measures how much useable energy is stored in a given volume, like mass density measures the mass in a given volume. Conventional rechargeable batteries can't match gasoline and that limits batteries from competing with the internal combustion engine.

Work on the hydrogen fuel cell is much more promising. Hydrogen provides greater energy density then petroleum, and the fuel cell has been around for a long time now. It has been used in military and space applications. The biggest commercial hurdle is how to store roughly 10 kg of hydrogen in a car so that it has a range of 500 km, like a gas-powered vehicle. This is an active area of current research, and when solved can lead to a wholesale replacement of gas engines as we know them today.

Muon I have a question that possibly you can answer. Where do you get the hydrogen from? I know of two ways, both of which have problems. You can get it from water through electroysis or extract it from hydrocarbon fuels like oil or methane.

To get it from water you must put in more energy that you will get out so that will  create a huge electricity demand. Most of our electricity comes from coal burning plants which produce mostly CO2 as a product of combustion. This could eliminate our need for foreign oil but would still leave us with the greenhouse gas problem (assumming it is a problem).

If we get it from oil we are still dependent on oil. Also oil contains much more carbon by weight than hydrogen, so what happens to the carbon?

You are correct that most hydrogen comes from hydrocarbons today. The most common technology converts methane in natural gas to hydrogen and carbon monoxide. 

That sounds worse than producing carbon dioxide, since carbon monoxide is a deadly poison.

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That would be slick if it can be made to work. But it still seems that there are some significant technical problems to be solved.

When I was in college over thirty years ago it seemed like fuel cells were likely to become viable for cars, but many of the  problems which existed then are still around today.