Hydrogen fuel-cell cars may be on the road sooner than expected. Analysts predicted that the costly nature of hydrogen fuel-cell technology would prevent us from seeing consumer hydrogen powered automobiles for 10 years or more. But Honda is challenging that prediction: The company announced it will produce a consumer model in the next three to four years.

The car uses electricity generated by hydrogen to power its motor. As a fuel, hydrogen is more efficient than gasoline; as good as $0.20/gallon equivalent, meaning 20 cents of hydrogen fuel yields the same amount of energy as a dollar's worth of gas. It also burns significantly cleaner: Hydrogen cars emit nothing but clean, safe water. Overseas, Britain is already trying out this technology. The country's first hydrogen filling station opened last year in Hornchurch, Essex, and a line of hydrogen-fueled buses are already cruising London streets.

Experts doubted the possibility of a consumer line of hydrogen cars because of the expensive nature of the technology and the lack of hydrogen fueling stations to make use of it. Honda hopes to begin resolving these issues by developing a smaller, more efficient fuel cell to increase power and cabin space. The company is also working on an energy station that derives hydrogen fuel from the natural gas already in your home, allowing owners to refuel without leaving the driveway. If all goes as planned, we can say hello to hydrogen by 2010.