Fuel cells go the extra mile

energy production
Comparing two energy production pathways, © FZ Juelich

Are batteries or fuel cells the more environmentally friendly, technically superior and economically prudent solution for electric transportation? Short answer: It depends.

A great many studies have been published on the subject in recent months, one of which was conducted by Fraunhofer Institute for Solar Energy Systems – ISE on behalf of H2 Mobility. Titled “GHG emissions from battery and fuel cell electric vehicles,” it looked at the entire lifecycle of a car, including the manufacture, use and disposal of batteries, fuel cells and hydrogen tanks.

The study compares a Hyundai Nexo-type fuel cell vehicle with a power output of 95 kilowatts, a 5.6-kilogram hydrogen tank and a range of over 500 kilometers (310 miles) with an all-electric car equipped with a 60- or a 90-kilowatt-hour battery for driving around 300 to 400 kilometers (190 to 250 miles; curb weight excl. battery pack: 1,600 kilograms).

The key takeaway for the years between 2020 and 2030 is that the manufacture of the fuel cell model creates fewer GHG emissions than either the 60- or 90-kilowatt-hour battery electric vehicle. Today, manufacturers of all-electric cars still have to contend with a great deal of what could be called climate baggage, though further advances in technology will make this less of a problem eventually. “Even if you count GHG emissions over the entire lifecycle of the car, fuel cell vehicles retain their advantage. The higher efficiency of battery electric cars is insufficient to compensate for the GHG emissions from their manufacture,“ at least, if assuming a lifespan of 150,000 kilometers (93,000 miles), André Sternberg, a researcher working for Fraunhofer ISE, said.

In this scenario, a 90-kilowatt-hour battery electric vehicle that receives its energy from the grid comes to 0.18 kilogram of CO2 per kilometer (0.29 kilogram per mile), while a fuel cell electric vehicle using hydrogen produced by burning natural gas emits 0.15 kilogram of CO2 (0.24 kilogram per mile). The same ratio can be observed if electricity is generated by wind turbines or solar PV. Only if a BEV is equipped with the smaller 60-kilowatt-hour battery do both vehicles have the same carbon footprint.

read more in H2-international May 2020

Edgar Lange

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