How big environmental gains that can be made by using hydrogen as an energy carrier depends on how the hydrogen is produced and transported and how efficiently it is converted.
There are mainly three areas of use where the environmental potential of hydrogen is particularly significant: transport, industry and as an intermediate storage of renewable energy. By using hydrogen together with fuel cell technology, the local emissions of carbon dioxide, nitrogen oxides and particles from the transport sector can be radically reduced. Although hydrogen produced from fossil energy sources has an environmental impact, it is an advantage that the carbon dioxide emissions can be separated already in the production plant.
This becomes clear if hydrogen is used as vehicle fuel, as emissions from each vehicle are avoided. The emissions from a fuel cell together with hydrogen is pure water. It provides great environmental benefits, provided that the steps before the user stage do not entail a large environmental burden. A fuel cell is approximately three times twice as energy efficient as an internal combustion engine if used in a normal car. This means that with the same amount of energy, the mileage is triple with a fuel cell car.
Hydrogen has a central role as support in the development of renewable energy systems. Sun, wind and wave power are by nature uneven as energy sources that need to be supplemented with methods of intermediate storage. Here, hydrogen can function as a power equalizer and storage of excess energy. Energy storage in hydrogen would make energy systems with for example, wind power more flexible and contribute to increasing the rate of expansion of renewable energy.
