Hybrid cars will have substantially more environmental benefits than hydrogen fuel cell cars until at least 2020, according to a new study in the US.

Hydrogen fuel-cell vehicles have low emissions and energy use on the road, but converting a hydrocarbon fuel such as natural gas or petrol into hydrogen to fuel such vehicles uses substantial energy and emits greenhouse gases, the study said.

The Massachusetts Institute of Technology study was published after the Bush administration announced in January an initiative to develop hydrogen fuel cells. The initiative will receive $1.2bn in government funds.