Previously in this series, we’ve looked at battery electric vehicles (BEVs). Among the alternatives to conventional internal combustion engine (ICE) vehicles, BEVs have attracted the most media attention, thanks in part to the razzamatazz around each new Tesla launch.
But away from BEVs, another serious contender to replace petrol and diesel has been establishing itself in the wings: hydrogen.
Hydrogen is the most abundant element on Earth. In principle, this makes it a prime source of cheap energy. It’s also clean: it produces water when you burn it. However, it is also highly flammable. So rather than burn it in the way you ignite petrol to move a piston, hydrogen-powered vehicles have a fuel cell that uses hydrogen to generate electricity. Vehicles using this technology are termed fuel cell electric vehicles (FCEVs).
The fuel cell generates electricity from the hydrogen using reverse electrolysis1. Hydrogen reacts with a catalyst, typically platinum, resulting in the desired electricity, as well as waste heat and water. You need to combine multiple fuel cells to power a car. Once the reverse electrolysis process starts, any excess energy can be stored in a battery, though these are smaller than the traction batteries in BEVs. This battery can also be used to capture energy generated by braking.
Hydrogen Storage
A recent breakthrough in gas storage technology could now make it easier and cheaper to store Hydrogen on a vehicle. Ordinarily the gas is stored at high pressure (around 700 bar), but researchers from Northwestern University in Evanston, US now believe they have developed a solution that replicates a sponge and can store high volumes of hydrogen at much lower pressure.
The highly porous material NU-1501 is described as a metal-organic framework that can potentially store hydrogen and other gases at much lower pressures, reducing the required tank size. Having said this, the new material will require support from car manufacturers if it is to become useable in the automotive industry.
Hydrogen safety
While hydrogen is extremely flammable, auto industry experts have highlighted that petrol is too. Moreover, they point to the fact that hydrogen quickly dissipates into the air if there is a leak in the tank, where petrol forms a highly flammable pool beneath2.
Research by the University of Miami compared the severity of a fuel leak and ignition in both a petrol and hydrogen vehicle. It concluded that ‘the damage to the gasoline-powered vehicle was severe while the hydrogen-powered vehicle was undamaged’3.
Hyundai has outlined some of the tests it has carried out on its hydrogen tanks, saying they have withstood being dropped from 1.8m and that when punctured, either by a bullet or a rear-impact test, the hydrogen quickly dissipated into the atmosphere without causing an explosion4. Its Nexo FCEV did extremely well in independent crash-safety testing5.
FCEV range
Current FCEV models can achieve impressive ranges. Hyundai claims the Nexo, for example, can achieve over 660km on a single tank, powered by a 120 kW electric motor generating 395 Nm of torque. And, like their fossil-fuel counterparts, FCEVs can be refuelled in minutes. This results in a driving experience much closer to what motorists are used to, while use of the vehicle itself generates no carbon dioxide (CO2).
Adoption hurdles
There are three main hurdles FCEVs are currently facing, when it comes to expanding their adoption. The first is how the hydrogen is generated6. One process, known as steam reformation, uses methane and generates a lot of gases linked to global warming. However, alternative methods such as electrolysis, can be very low-carbon, provided the electricity comes from a renewable source.
The second challenge is refuelling. Until there is greater adoption of FCEVs, few businesses appear willing to invest the significant amounts needed to build widespread fuelling infrastructure. And of course, while refuelling options remain limited, FCEVs will be less attractive to drivers.
The final challenge is the price. FCEVs currently start at around €60,000, while BEVs are available from around €21,0007. Without the demand for FCEVs, supply volumes don’t reach levels that result in price-drops.
Expansion of fuelling stations
To overcome some of this chicken-and-egg situation, countries such as Germany are funding coordinated roll-outs of hydrogen refuelling stations. H2 MOBILITY is formed of traditional energy suppliers and automotive heavyweights, with a goal of establishing 100 hydrogen stations by the end of 20208. A further 300 should follow as vehicle numbers rise. Furthermore, a study by the Jülich Forschungszentrum shows that implementing the hydrogen refuelling infrastructure for FCEVs will cost €11 billion less than that needed for charging BEVs9.
With hydrogen in such abundance and the costs for its conversion into electricity coming down, new automotive opportunities arise. As we have seen, high-speed BEV DC chargers delivering 350 kW of power require serious electrical infrastructure. The cost of this could be prohibitive, especially in remote regions. Indeed, companies such as AFC Energy are seeing this as an opportunity to create hydrogen-powered charging points for BEVs10. Their CH2ARGE system could conceivably be installed as the charging solution in certain places, or as a trial platform to understand whether there is sufficient demand at a location to justify investment in electrical infrastructure.
Will hydrogen fuel cell vehicles displace battery electric vehicles?
Hydrogen-fuelled FCEVs provide a car ownership experience that comes closer to that of combustion engine vehicles than BEVs achieve. Their range and refuelling time are comparable, while their use results in lower carbon emissions than ICE vehicles – provided the hydrogen is generated using electrolysis and renewable energy. Being electric at heart, they offer a similar driving experience to BEVs and can benefit from many of the same motor and electronics technology advancements. But which technology will win? To find that out, we need to look to the future, which is what we do in the final instalment of this series.
The next, and final, blog in the series will look at: The future
- To read the previous blogs in this series follow the links below.
