1.   But other forms eventually arose which were able to extract hydrogen from a very much more widespread source - water.

2.   The cell must be plugged into the mains overnight to extract the hydrogen.

3.   But when hydrogen is extracted from gas, the residual carbon must somehow be disposed of, possibly by pumping it back into depleted oil and gas wells.

4.   Most hydrogen cells extract hydrogen from hydrocarbons like gasoline, natural gas or methane.

5.   Steam will break down the methanol and extract hydrogen to be combined with oxygen from the air.

6.   The alternative is extracting hydrogen from a hydrocarbon such as oil, methanol or natural gas.

7.   These could be used to directly inject hydrogen into fuel tanks or to inject natural gas from which pure hydrogen would be extracted in the vehicle.

8.   Unfortunately, the atoms are so firmly locked that present methods use more energy to extract hydrogen than can be produced by the fuel.

9.   A reformulator extracts hydrogen from those fuels, but those vehicles do emit some greenhouse gases.

10.   As an interim step, Burns said the industry would have to settle for fuel cells that include on-board reformers which extract hydrogen from gasoline.