If hydrogen vehicles were to replace all combustion engine vehicles, what would be the carbon output decrease?

Question

Would this be enough to save the planet and turn the current crisies into a non issue?

Answer 1

Not at this stage.

Hydrogen is a clean fuel, but it is not the magic bullet it is being made out to be.

Hydrogen needs to be manufactured. Using current techniques it would actually increase co2 emissions. (Significantly)

1 Reforming natural gas produces co2 and destroys an already useful fuel.

2 Electrolysis is only theoretically 66% efficient. This means at least 34% of the electrical energy is wasted in the production of hydrogen. The electricity could be produced using low co2 techniques. This does not make sense in comparison to current battery efficiency. (Lithium Manganese is around 90% in out efficient.)

3 Biochemical production does show promise but this is some way off.

A vehicle can be made more efficient by. (In order most to least)

1 Reducing its wind drag. A factor of cross sectional area and shape (cd)

2 Reducing its rolling resistance. A factor of weight and friction.

3 Improving engine efficiency. Energy consumed versus power out. (Including fuel production)

If you do the number crunching Hybrids are the lowest co2 emitting MOTOR vehicles on the market at present.

Electric and Hydrogen powered vehicles on low co2 energy are better. Each unit of clean power they use could replace a unit of dirty power.

If you want to crunch numbers

Petrol/Gasoline produces 2.32kg of co2 /l (19.4 lb/ us gal)

Diesel 2.66 kg of co2/l (22.2lb/us gal)

Lpg 1.5kg of co2/L (12.9lb/us Gal)

Coal fired electricity 880-960 g/kwh (400-436 lb/kwh)

Riding a bicycle zero ( 1kg/2.2lb /day per person fit or not)

The most promising temporary measures at present

1 Clean coal technologies. Able to retrofit to existing power stations reducing co2 emissions to near zero

2 Nuclear power. The "Mother in law solution" should do the job but comes with a price.

Only long term solution

Combination of renewable energy sources. solar, hydro, tidal, geothermic, etc

Answer 2

Vehicles currently account for about 25% of total CO2 emissions, so switching over to hydrogen would only reduce the total, under optimum circumstances by 25%. But current technology is most efficient at getting hydrogen from natural gas, so the reduction would be significantly less.

To answer the second question, any reduction would help, but the majority of CO2 emissions come from energy and industry. Since energy still comes primarily from fossil fuels, and developing countries are primarily building coal fired plants, which are the worst for CO2 emissions, any gains from hydrogen power vehicles would be wiped out relatively quickly.

If, however, most new power plants were nuclear, solar, or wind the combined reduction with hydrogen vehicles should reduce emissions enough to ensure that the problem would no longer be a major issue.

Answer 3

Fuel cells are more efficient which should somewhat ofset the lower energy content per volume of Hydrogen. Though there is no reason why you can't just burn it in an Internal combustion engine. BMW and Mazda have built cars that run on hydrogen using internal combustion engines and possibly some others too. Another reason to prefer fuel cells is that they don't operate at temperatures anywhere near as high as combustion engines thereby preventing a lot of Nitrous Oxides from being released.

Answer 4

Not much of a decrease.

Because I'm betting all the electricity we'd have to produce to make all that hydrogen would come from fossil fuels. Unless you've found that hydrogen well we've all been looking for.

Secondly, not a chance. Transportation is about 1/4 of the carbon output of the US and far less in every other country.

The environmentalists say we need to reduce our output to 20% of 1990 levels to REDUCE AGW. That means we still would have to find more ways to reduce CO2 output.

Thanks for playing.

Answer 5

That partially depends on how the hydrogen is produced. Hydrogen is produced as a by-product from many chemical processes. It would reduce the carbon footprint, but by how much is really unsure. Yes, the cars that run on it would be emitting a zero footprint. However, you have to look at the total process: manufacturing it, transporting it, etc. You never will get rid of the total foot print.

Answer 6

Hydrogen cars themselves won't cause a change. But they will enable ANOTHER change to occur.

Right now cars use gasoline, and that cannot be made CO2-free. Electric cars and hydrogen cars are CO2-free, but their fuel will be made from electricity, so they're only as clean as the electric power plants.

Then all we have to do is clean up the power plants. And making CO2-free power plants is easy with existing technology. They would need to be built, but they can be.

Answer 7

That would totally depend on the method used to manufacture the hydrogen. If it was the electrolysis process wherein electricity from a fossil fuel plant supplied the current, that might not cut it.

However if the power came from a nuclear plant (or solar or wind) well.....maybe!!!!!

Answer 8

My word, it would be almost totally zero. The carbon footprint of a hydrogen car is almost nothing.
Oh yeah, and they have found a plausible way for hydrogen to be utilized by cars, and a nice cheap way to produce hydrogen from water, but if they shared that with all of us...well, that would mean an end to big business. And they don't want that.

Answer 9

Absolutely... there is no carbon in Hydrogen... but it would make no difference what so ever in Global Warming as it is not carbon caused...