They are already building them in China.

Everyone agrees that electric rail transportation is the greenest way to go, but hanging the wires needed to convert from diesel to electric can be very expensive, particularly if there are a lot of bridges that have to be rebuilt to accommodate the overhead wires and pantographs that transfer the electricity to the train.

In Ontario, Canada, the government is considering an alternative to overhead wires: hydrogen powered fuel cells. But as John Michael McGrath points out, fuel cells are like unicorn dreams, “the wonder technology of the future for the past 20 years”; and as we have pointed out, hydrogen is either stripped out of natural gas or made with electricity, which pretty much makes it an expensive battery.



© Battery UniversityBut there is another alternative, one that we have dreamed about for years on TreeHugger: supercapacitors. Unlike batteries, which store electricity through a chemical reaction, capacitors store energy in an electric field. They cannot hold as much energy as a battery but because there is no electrochemical reaction, they charge up almost instantly. As Battery University explains,