Why do some people think hydrogen is the better option?
Cars powered by hydrogen fuel cells have, to the casual observer, a number of advantages. Like a petrol or diesel car they can be refuelled quickly (in around five minutes) and can deliver long ranges (up to 400 miles). As they don’t have large traction batteries, they require fewer non-sustainable raw materials such as lithium and cobalt in their construction.
However, while the user-experience of a fuel cell car might appear attractive (long ranges, short refuelling times etc) they currently have a number of drawbacks. The first is the environmental impact of production process, or the ‘well to wheel’ calculation that governments and legislators around the world are looking to minimise to reduce CO2 emissions.
Put simply, the process of creating electricity from hydrogen is vastly less efficient in terms of CO2 emissions than generating electricity, transporting it via the grid and storing it a battery. Before the hydrogen in your car can produce electricity to drive the wheels it needs to be created, transported and stored. And that’s where the argument for hydrogen starts to fall down.
With battery-powered vehicles only eight percent of the energy is lost during transport before the electricity is stored in the vehicle’s batteries. When the electrical energy is converted to drive the electric motor, a bit more is lost. Depending on the model, battery-powered electric cars achieve an efficiency of between 70 to 90 percent.
In the case of a hydrogen-powered car the losses are much greater. 45 percent of the energy is lost during the production of hydrogen through electrolysis, liquification and transport. Of this remaining 55 percent of the original energy, even more energy is lost when converting hydrogen into electricity within the vehicle. This means that a hydrogen-powered vehicle only achieves an efficiency of between 25 to 35 percent, depending on the model.
The bottom line in terms of efficiency is that a hydrogen fuel-cell car consumes two to three times more electricity for the same distance than a battery car.
Hydrogen fuel cell cars are mechanically far more complicated than simpler battery-only cars.