Fuel cells in mobile applications

‘The only thing that comes out of the exhaust is water vapour!’ In light of climate change and smog, such statements seem attractive at first. No wonder most major car manufacturers have been working on fuel cell cars at some point or another;16 these cars would have electric drive trains powered by electricity from fuel cells. A number of different concepts have been investigated: fuel cells with hydrogen, methanol and natural gas.

In the mid-1990s, the first prototypes were presented. Daimler-Chrysler also launched a test fleet of 30 buses and 60 cars in 2002/2003.17 Volkswagen has discontinued its research on hydrogen drive systems and BMW discontinued its field tests on hydro­gen as a fuel for cars with conventional engines in 2009 .18

Today, no market launch is in sight.19 One reason is the high cost; fuel cells for cars still cost around 100 times as much as an inter­nal combustion engine. In addition, there is no hydrogen infrastructure, and the cost has been estimated at €80 billion for a network of 2000 hydrogen filling stations – and that would only cover densely populated areas in Germany. In light of such figures, fuel cell hype has died down considerably.20

One crucial aspect is often overlooked when assessing hydrogen-powered fuel cells. If renewable electricity is used to generate hydrogen for a fuel cell in a car, the car makes do with less conventional fuel, leading to 190g fewer emissions of climate gases per kilowatt-hour.22 But because that kilowatt-hour was not sold to the grid, other power plants will have to generate it, increasing emissions by 590g (see Figure 8.5). In a holistic view, the use of ‘green hydrogen’ does not actually reduce emis­sions in our current power supply system, but rather increases emissions of climate gases.23

If at all, hydrogen produced from renewable power for fuel cell cars is a very long-term option for the Solar Age. The highly detailed publications about research into and tests of emission-free fuel cell cars24 therefore should not mislead us into believing that the acute problems in our transport system can be solved this way. Car travel needs to be avoided more often, conventional cars need to become more efficient and emit less pollution, public transport needs to be used more often, and speed limits need to be reduced.

Not even the environmental benefits are convincing if we look at them closely. While fuel cell cars are very efficient, especially in partial load, a lot of energy is needed to provide the fuel. When we compare fuel cell cars running on various types of fuel to conventional cars in terms of environmental impact, the benefits are slight, and technical progress with conventional cars is also expected in the years to come.21

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