The U.S. National Academies has published a study according to which mainstream introduction of fuel-cell cars is a necessary, but extremely expensive thing. And how much does extremely expensive mean? Well, about $200 billion, the report says.

The money should come from both the government and the car manufacturing industry. In order to make the technology widely available and affordable, the government will have to pump about $55 billion in subsidies over the next 15 years, if a number of 2 million hydrogen powered cars are to be seen on the roads in the United States by 2023. The industry will have to come up with the remaining $145 billion.

Fuel-cell vehicles run on hydrogen and the gas emissions they produce consist only in water vapors, which don't affect the environment in any way. Conventional cars, on the other hand, are responsible for one fifth of the total amount of CO2 emissions, the gas that is considered to contribute the most to global warming.

The main reason for which fuel-cell cars cannot be made available right away is that they are very costly to produce and there is no infrastructure to distribute hydrogen. While gas companies say they will create this infrastructure as soon as more hydrogen powered vehicles will hit the roads, car manufacturers claim that more hydrogen filling station are needed for them to create and release this sort of vehicles on the market.

The report also said that the government shouldn't focus only on helping the fuel-cell industry. If it wants to protect the environment, the government should help manufacturers pursue other types of technologies like biofuels and fuel-efficient conventional vehicles as well.