Then they had to make them affordable and the fuel able to be widely available. All of these obstacles have been overcome yet fuel cell cars still have not been mass adopted.
That is because they were not found to be very efficient. To produce the gas, compress it, and transport it is costly. However, there is a special little fuel cell car called Rasa that is drastically more economical and its creator has come up with a more efficient hydrogen distribution system too. The car and the system around are both part of a grand plan by the company Riversimple, founded by Hugo Spowers, former motor racer and mechanical engineer of race cars.
15 years ago Spowers stopped working with internal combustion engines when he had the idea of building a hydrogen-powered vehicle. He was determined to find a fundamental solution to the problems associated with carbon emissions and so he hand-built an aerodynamic car which weighs only 580 kilos, 40 kilos more than the battery of a Tesla Model S car.