“We’re not about to give up on hydrogen electric fuel-cell technology at all”. That’s what Toyota chairman Takeshi Uchiyamada had said to journalists at the Tokyo auto show in 2017. Meanwhile, Elon Musk is on record as saying that he finds the technology’s real-world feasibility “mind-bogglingly stupid”.
Toyota has since doubled down on hydrogen fuel-cell vehicles (HFCVs) and hydrogen itself, but EVs are clear winner when it comes to 2Ws, 3Ws and cars for the following reasons:
- The technology has a growing network of chargers across India (and other countries)
- EV batteries are increasingly more energy-dense and the option to generate electric power at a recharging station makes it incredibly convenient for charging station owners to set up the infrastructure in the first place
Hydrogen, on the other hand, must be generated offsite at refineries or electrolysis plants, transported and stored under safety precautions (as it is flammable) before refueling vehicles.
Yet, hydrogen could be useful for the other category: heavy transport vehicles. This is due to two factors:
- Energy density
Hydrogen’s energy density of 33.6kWh/kg is the highest of all fuels ever discovered. The keyword here is density as it allows hydrogen to pack incredible amounts of energy per unit weight, and this makes it near-ideal fuel for heavy vehicles like multi-axle trucks and buses, trains, aircraft and shipping vessels.HFCVs bring down the energy density to around 6.5KW/M3, but they are still quite popular in factories and warehouses for forklifts. China and Germany are already running fleets of HFC buses and Germany has also launched the world’s first HFC passenger train. Called the Coradia iLint, it runs completely on hydrogen fuel cells across non- or partially-electrified tracks.The technology is suitable in this context because the primary design requirement behind any large goods or people transporter is to maximise its payload capacity. It means that the vehicle weight has to be optimised to ensure that:
- The mass of the vehicle itself is adequate enough for it to be structurally safe
- That its gross weight (including its payload and on-board fuel) achieves a certain minimum driving range.
The governing equation behind this necessity is found in this paper. So the higher the energy density of the fuel, the further it can drive per unit weight.
Fig. 1: The Tesla Semitruck is the world’s first all-electric truck and runs fully on li-ion batteries | Image: Ptolemus
With Toyota’s dogged determination to promote HFCVs, further research is bound to boost their energy density while compressing their form factor. EV batteries at the moment are not capable of supplying as much energy without adding a lot of weight. For example, the best commercially available solid-state li-ion batteries currently offer around 400Wh/kg, while one has reported an energy density of up to 506 Wh/kg km under laboratory conditions. Still, it’s not close to that of HFCs.
Contrary arguments will point out the examples of the electric aircraft Alice and container ships like the Yara Birkeland. But the Alice is a 9-seater aircraft with a range of 250 nautical miles only (463 km), while the form factor of a ship and the buoyancy it receives from water affords its designers a lot more room for the weight of the batteries.
Fig. 2 : Eviation’s Alice is the first all-electric aircraft that is scheduled to go into commercial service | Image: Eviation
- Refuelling time and range
HFCVs can be refuelled in about 6 minutes, vs. 20 mins to 8 hours for EVs. The former also offers greater driving range per tank of hydrogen. These differences are some of the attributes that Toyota premised the Mirai around, which is a fuel-cell passenger car that was introduced in 2015 and has so far sold 21,475 units globally. It can drive for around 647 km on a full tank of hydrogen and has a refuelling time of just around 5 minutes. A certain Mirai was even hypermiled to 845 miles (1,352 km) on a single tank of hydrogen in 2021.
Fig. 3: Toyota’s Mirai entirely on hydrogen fuel cells and offers around 600km on a full tank | Image: Toyota USA
Meanwhile the Tesla Model 3, one of the most popular EVs on sale today, goes for between 290 - 595 km on a single charge (depending upon which battery pack it’s using) and takes around 15 minutes to charge at a Supercharger (which is not recommended for repeated use). Granted, there has been tremendous progress on increasing the range of EV batteries and Samsung has even revealed a solid-state battery with 500 miles of driving range. But for now, HFCs have the advantage in this aspect.
Hydrogen’s place in India’s e-mobility
As automakers move away from lithium, cobalt or liquid electrolytes (that have a fire risk), the industry will become the dominant option for personal mobility. This will be complemented by the growing network of EV chargers in every major market. India, for instance, currently has 5254 public EV chargers but the government plans to have 46,397 chargers installed by 2030. China had 1.8 million public EV chargers in 2022 — more than the rest of the world put together — and the country’s pace of infrastructure addition will impact the EV industry far beyond its borders.
Fig. 4: India’s diesel trucks are a major source of particulate matter and CO2 emissions | Image: GreenBiz
Hydrogen FCVs would only make sense for India for its fleet of diesel trucks and buses. India has announced its target of producing 5 million tonnes of green hydrogen by 2030, and green hydrogen could be used to lower the country’s road transport emissions. The sector accounts for 90% of India’s transport emissions, and the diesel trucks alone are responsible for 40% of the sector’s carbon footprint.
However, turning hydrogen into a feasible option for India will take significant investments to the surrounding infrastructure. Carbon fibre tanks to store the hydrogen are only a first step, and the country only has two refuelling stations at the moment. The vehicles themselves will have to be heavily subsidised for their per kilometer running costs to be comparable to that of the EVs or ICEVs.
At the same time, though, moving to green hydrogen and hydrogen fuel cells for India may not be particularly difficult as its 81,099 petrol and diesel pumps could be upgraded as hydrogen storage and retail points. Just as with EVs, HFCVs will need support from the government in terms of long-term subsidies and assistance to set up an adequate number of refuelling stations. If that is achieved, India could embrace an entirely new branch of industry while making enormous strides towards its larger climate commitments.