[T]he governor has thrown his weight behind “Hydrogen Highways,” an ambitious but costly plan to build a statewide network of 200 hydrogen filling stations by the end of the decade. The investment is necessary, proponents say, because without refueling stations, automakers may not produce enough of the alternative cars and consumers will not buy them. Stations would be located every 20 miles along major highways and interstates. Each station would cost $250,000 to $500,000, and the total expense could run into the hundreds of millions of dollars. The undertaking would be financed with a combination of public and private money. The governor’s proposal is part of a broader effort in California and across the nation to promote hydrogen fuels, which offer the promise of cars that emit few or no air pollutants. Feeling a little uneasy about government’s ability to steer innovation toward a particular solution? Perhaps you’re remembering past attempts: California authorities promoted methanol as a replacement for gasoline in the 1980s, but it did not work out. In the ’90s, battery-powered electric cars stalled because of technological limitations. Read the whole story here.