Right now, we have the technology to produce hydrogen from water or from natural gas at small-scale, onsite energy stations, then use the hydrogen to power zero-emission fuel cells.

The greatest challenge is that it takes energy to produce the hydrogen. Reforming natural gas does create some pollution, though less than burning it does-and far less than burning diesel. Likewise, the electricity used to extract hydrogen from water may come from a polluting source.

In an ideal future, people could use clean, renewable, solar or wind power to split water into hydrogen and oxygen. In fuel cells, we would then recombine hydrogen and oxygen to produce water and electricity. The same amount of water would come out of the system that went in at the start. The hydrogen would merely act as an energy carrier for the solar or wind-generated electricity.

The earth has no shortage of wind and sunshine for power. There is enough wind in Kansas, Texas, and North Dakota alone to power the entire country. Enough sunlight hits the earth every minute to power the entire world for a year.

We can have clean, renewable power, not just for our electric grid, but for our vehicles as well.

It's an amazing, tantalizing possibility. The question is, how do we get there?

Peter Lehman of the Schatz Energy Research Center has likened the challenge to building the interstate highway system. It will take many years, and a great commitment of will and resources. But we can do it. And like a highway system, it doesn't need to be built all at once.

The beauty of a decentralized power system is that small-scale, onsite energy stations do not rely on creating a whole new infrastructure. Stations can be built one at a time. Initially, this approach makes most sense for fleet applications such as bus transit systems. Every night, the buses return to the same location for refueling.

By demonstrating that fuel cell transit can work efficiently and cost-effectively, we will open the market for more fuel cell applications, bringing down the costs as demand increases.

Curbing our reliance on fossil fuels will take a combination of market demand, technology development, and political will. We need to make sensible choices. Burning more coal to produce electricity for electrolysis would probably make our environmental situation worse. Fostering the growth of clean, renewable electrical generation would almost certainly make it better. The HyRoad Vision requires all of us to look at the big picture. We need to invest in technology development to make the Zero Pollution Solution a reality. AC Transit's fuel cell demonstration project is one huge step on the HyRoad to a sustainable future.