________________________________________________________________________________________________________________________
Hydrogen as a fuel and a mechanism for transporting energy has very significant potential as an alternative to storing energy in batteries. Unlike burning diesel, petrol or natural gas, combustion of hydrogen produces no CO 2
. However, when burnt it still produces low levels of pollutants( such as NOx) and is also inefficient in converting fuel to energy, typically below 40 percent efficiency. The alternative is to convert the energy directly from hydrogen to electricity using an electrochemical process, which is what a fuel cell does.
As the energy in hydrogen is stored either as a gas or liquid, it has a much higher energy density than batteries. In practical terms, this means that for the same system mass or volume, a fuel cell and hydrogen can deliver up to three times the range achievable with batteries. This is particularly advantageous for heavier vehicles or those wanting a longer range, where just adding a bigger battery is not an option. In applications such as flight, batteries are not a practical option and a higher power density technology like hydrogen and fuel cells is really needed.
Hydrogen vehicles can also be refueled in the same way as petrol or diesel vehicles and only take slightly longer to fill up. This is beneficial when looking at the level of infrastructure to support zero emission vehicles, as one hydrogen refueling station can support ten times more vehicles than a battery charging station. It’ s true that it’ s more practical to charge battery vehicles at home or work, than it is to refuel with hydrogen, but the limitations on electrical grid capacity will restrict that ability as more battery vehicles are deployed.
Today the cost of fuel cells is higher than batteries, but if similar volumes are produced in the future, then fuel cells can be more
16