Patrick Molloy at Rocky Mountain Institute runs through the pros and cons of hydrogen fuel cell vehicles (FCEVs). The big pluses are that hydrogen has an energy density of around 120 MJ/kg, almost three times more than diesel or gasoline. Half the energy generated by an internal combustion engine is wasted as heat, whereas electric drivetrains used by FCEVs only lose 10%. Nikola Motors, a U.S. maker of hydrogen trucks, claims its vehicles can get 12 to 15 mpg, well above the average 6.4 mpg for a diesel truck. But hydrogen production needs to scale up rapidly and reduce costs. The fuel needs transportation and storage infrastructure (though producing hydrogen “anywhere” or using existing gas pipelines can solve this). And diesel trucks beats hydrogen on range (though 500+ miles seems plenty). What are the drivers? The EU has committed to removing gasoline and diesel vehicles by 2030. California and Canada have similar ambitions. Japan currently has 3,400 hydrogen vehicles on its roads and wants this to increase to 800,000 by 2030. China’s target is 1 million by 2030.
Although hydrogen fuel cell vehicles (FCEVs) have been around since the 1960s, they have recently emerged as a potential solution to decarbonise heavy transport. Nikola Motors just announced it has raised $1 billion in funding for its hydrogen vehicle technology, adding some substantial new partners including CNHI and Bosch. Earlier this year, the company also launched a daring roadmap for 700 fuelling stations across the USA and secured an 800-vehicle partnership with Anheuser-Busch to help decarbonise its freight fleet.
What makes FCEVs a good choice for decarbonising heavy transport? Let’s examine the similarities, advantages, and challenges of FCEVs compared with conventional internal combustion trucks.
Hydrogen fuel pumps: same as diesel, gasoline
One of the benefits of FCEVs is that hydrogen uses a fuelling infrastructure that’s similar to conventional trucks. This means that FCEVs could be refuelled at existing truck stops across the country and the fuelling experience would be similar. A truck can be filled with hydrogen in less than 15 minutes and the process of fuelling a FCEV is similar to fuelling a diesel truck; hydrogen gas is pumped into the vehicle tank using a gas pump and nozzle that is similar to a traditional diesel pump.
Higher energy density
Another advantage is hydrogen’s energy density. Diesel has an energy density of 45.5 megajoules per kilogram (MJ/kg), slightly lower than gasoline, which has an energy density of 45.8 MJ/kg. By contrast, hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. In electrical terms, the energy density of hydrogen is equal to 33.6 kWh of usable energy per kg, versus diesel which only holds about 12–14 kWh per kg.
What this really means is that 1 kg of hydrogen, used in a fuel cell to power an electric motor, contains approximately the same energy as a gallon of diesel. Taking this into consideration, Nikola claims its vehicles can get between 12 and 15 mpg equivalent, well above the national average for a diesel truck, which is around 6.4 mpg.
Much less heat loss
Electric drivetrains are also more efficient than internal combustion engines. With an internal combustion engine, approximately 50% of the energy generated is transferred to heat; but electric drivetrains only lose 10% of their energy to heat. This efficiency difference shows just how much consumers are losing with less efficient internal combustion engines.
Price is another attractive attribute of hydrogen. Diesel prices are currently hovering close to $3.00 per gallon, and with the recent curtailment of Saudi Arabian oil production, it’s reasonable to expect further price increases for diesel. But on the hydrogen front, recent analysis from Bloomberg New Energy Finance suggests the per-kilo production price for hydrogen could be as low as $1.40 per kilogram in about a decade.
Lighter fuel cell than batteries, longer range
When it comes to heavy transport, weight matters. FCEVs offer the same high torque that comes with battery electric vehicles, but at lower weight. An example is the estimated weight difference between the battery electric Lion 8 and the hydrogen fuel cell Nikola One; the Lion 8 has a 480-kWh battery pack with a 250-mile range, which equates to about 2–5 tons. A Nikola One, with a range of about 500-750 miles, is estimated to have a 250-kWh battery pack, which would likely weigh around 2.5-3 tons.
Taking these factors into consideration, there is a clear pathway for hydrogen to be a low-carbon, low-cost, low-weight alternative fuel for heavy-duty trucks.
However, FCEV trucks are not without their challenges.
Not enough “green hydrogen” production. Yet
Even though hydrogen gas has no colour or odour, to support the decarbonisation of heavy transport we will need green hydrogen and a lot of it. Green hydrogen, also called renewable hydrogen, is hydrogen that’s made using only renewable energy, typically through the process of electrolysis. Electrolysis of water uses electricity to separate water into gaseous hydrogen (H2) and oxygen (O2), converting electrical energy to chemical energy. There are still questions around how quickly the production of green hydrogen can scale; the manufacturing capacity for electrolysers is only starting to significantly ramp up.
Transportation and storage. How?
The main challenges with hydrogen come down to transportation and storage. Hydrogen is produced in gaseous form, and it needs to be stored under pressure or liquified directly. Both of these processes require additional energy, which may or not be from renewable sources.
There are emerging methods that use chemical bonds (typically referred to as liquid organic hydrogen carriers [LOHCs]) or ammonia to transport hydrogen in a stable state. These methods don’t require pressure or cryogenic liquification, and therefore require less energy to transport and store the hydrogen. However, the technology is still in a relatively early stage of development and is not ready for large-scale adoption.
Produce hydrogen locally? Use existing gas pipelines?
Another solution to transportation and storage challenges has been to focus on localised production. Nikola has partnered with Nel and Bosch to deliver a network of local hydrogen production stations that utilise renewable energy sources and electrolysers, thus cutting out the logistics chain of conventional diesel and gasoline supply.
In the future, we could also potentially use natural gas infrastructure to transport hydrogen, reducing the need for large infrastructure development. This could also offer a means to provide hydrogen from central production hubs rather than localised builds.
Diesel beats hydrogen on range
One other disadvantage of hydrogen is the range. According to Nikola, the range of a fuel cell truck is 500–750 miles, depending on load and terrain; Toyota Kenworth FCEV trucks have a range of about 300 miles. This pales in comparison with diesel trucks, which can go well over 1,000 miles without refuelling. However, with drivers limited to 500 miles a day, this factor may not cause a significant disruption to standard practice.
Clean fuel policies, investments
Even though there are challenges, the time for hydrogen is now, and here’s why:
We are seeing increased regulatory pressure and industry demand. The European Union has committed to removing gasoline and diesel vehicles by 2030. At the same time, clean fuel standards and associated investment in California and Canada are creating the policy basis for change. Hyundai is planning for the production of up to 700,000 FCEVs per year by 2030, and Japan is targeting 800,000 FCEVs by 2030. And, with technology costs that are anticipated to reach break-even with diesel trucks in several markets, there is significant momentum and investment in hydrogen.
The more projects that increasingly use fuel cell technologies, the more potential for cost reduction and investment in the technology. China’s commitment to get 1 million fuel cell vehicles onto the roads by 2030 (with $7.6 billion being invested in heavy-duty trucking) offers huge potential for significant advancements in the efficiency and cost points for fuel cell vehicles.
Hydrogen has seen false dawns before, but this low-carbon alternative is being pushed by some of the largest companies on the planet across multiple sectors. Toyota Kenworth has a long track record of developing trucks using fuel cell technology and in 2019 it added 10 T680s to be used at the Port of Los Angeles and throughout Southern California. Shell has recently invested heavily in large-scale hydrogen electrolysers, which offer a zero-carbon option for hydrogen production. Earlier this month, Cummins acquired a market-leading electrolyser and fuel cell manufacturing firm, Hydrogenics, for $290 million. These are all signals of serious commitment by industry leaders to move into the hydrogen and fuel cell space.
Rocky Mountain Institute (RMI) is working to identify the opportunities for green hydrogen to accelerate decarbonisation in sectors that have struggled to make progress, and we are only now starting to see the role and position this technology can have in decarbonising the freight sector. You can watch a panel discussion on hydrogen in trucking, hosted by the North American Council for Freight Efficiency (NACFE).
Patrick Molloy is a Senior Associate, Industry and Heavy Transport, at Rocky Mountain Institute
This article is published with permission. Copyright 2019, Rocky Mountain Institute