The world of personal transportation is in the midst of a seismic shift. Over the past decade – as the effort to achieve net zero has ramped up – a surge of investment into and demand for more environmentally friendly vehicles and their supporting infrastructure systems has shaken the auto industry. The primary catalyst for this shift has been the advancement of EV technology to solve reliability and efficiency issues coupled with a now robust infrastructure system to support them. Industry titans such as Ford, Toyota, and the Luxury brand Porsche, as well as newcomers such as Tesla and Rivian have all produced popular electric vehicle (EV) models. However, while EVs are undoubtedly at the forefront of sustainable personal transportation in the status quo, fresh innovations are on the horizon.
In this final edition of Fuels of the Future, we explore the feasibility and efficacy of hydrogen-powered vehicles in an attempt to answer the question: is hydrogen – the most abundant element in the universe – the next evolution in low-emission transportation? To do so, we look at the top two ways to power road vehicles with hydrogen and a critical supply constraint for producing hydrogen in the first place.
Hydrogen Fuel-Cell Vehicles (FCEVs): In many ways, FCEVs operate similarly to traditional electric vehicles. Instead of electric batteries powering the vehicle, FCEVs use gaseous hydrogen from onboard tanks to achieve a similar electric power result. In the vehicle fuel cell, oxygen drawn in from exterior vents and hydrogen from the onboard tanks combine and pass through the Polymer Electrolyte Membrane (PEM), which facilitates an electrochemical reaction that generates electric power for the vehicle. FCEVs produce non-harmful tailpipe emissions of water vapor and warm air, and operate between 40 percent and 60 percent efficiency, which is higher than internal combustion engines but lower than traditional EVs.
While still in relative infancy, FCEV technology is commercially available for consumption by the general population. The Toyota Mirai and Hyundai Nexo have been available since 2015. However, despite being available for nearly a decade there are only 17,000 Hydrogen-powered vehicles in the United States. While fuel cell electric vehicles utilizing hydrogen are most similar to battery-electric vehicles, there is another way to utilize hydrogen that is more similar to traditional gasoline cars – but with greatly different emissions results.
Hydrogen Combustion Engine Vehicles (HICEV): Hydrogen Internal combustion engines operate like traditional gasoline or diesel engines; however, modifications to the fuel injection and ignition systems are required to accommodate liquid hydrogen. They also operate at similar efficiencies – 20-40 percent – as traditional combustion. HICEVs utilize a pilot fuel – for example, biodiesel – mixed with a combination of hydrogen and air that generates an explosion to drive the pistons. Depending on the pilot fuel used in the engine HICEs can be completely carbon-neutral with the emissions being primarily water vapor.
Recently Toyota has been experimenting with liquid hydrogen in their internal combustion engines in its liquid hydrogen GR Corolla at the Fuji 24-hour race. Unfortunately, there are significant challenges with the technology. The need for liquid hydrogen to be kept at minus 253 degrees Celsius to prevent it from vaporizing or boiling causes the fuel pump to wear out quickly. This results from an inability to use traditional oil lubricants because they would contaminate the hydrogen fuel used in the vehicles and the issues associated with maintaining a good seal in the pump at the extreme temperatures necessary. Additionally, Toyota’s GR Corolla had limited range – only achieving a 65 km range with a 150-liter tank. For context, it is estimated a 700 Liter tank would be required to achieve a similar range to gasoline-powered vehicles. Innovation in this space is expected to improve efficiency and range.
Hydrogen Rainbow: Beyond the challenges of hydrogen vehicles themselves there is also a sourcing problem. Even though hydrogen is the most abundant element in the universe, it does not exist naturally as a gas. Rather it is naturally found in molecular form with other elements like carbon or oxygen and must be produced from different sources. Blue and Grey hydrogen are traditionally the cheapest sources but come from burning fossil fuels – like coal – which result in high CO2 emissions. Blue Hydrogen is less polluting than Grey Hydrogen and has the added advantage of capturing CO2 emissions, however, emissions cannot be entire removed from its production process.
Green Hydrogen on the other hand does remove emissions from the production process, but relies on extensive infrastructure buildouts. It is generated through a process called electrolysis in which an electrical current passes through water and breaks down the molecules into its respective oxygen and hydrogen components. Green Hydrogen is often viewed as the most sustainable way to centrally produce hydrogen, but in its current state is more expensive than the other methods. It also requires further infrastructure and transportation investments to get the green hydrogen to its end users. A more recent innovation in Turquoise Hydrogen that leverages distributed production strikes a balance by utilizing hydrocarbons – namely natural gas or CH4 – but splitting the molecule without combustion so that clean hydrogen gas and solid carbon powder are the only products. With that production process, natural gas running to existing facilities through distribution pipelines can be converted into hydrogen on-site and on-demand, further eliminating the need for storage tanks. That may be a silver bullet for improving the feasibility of hydrogen access and supporting infrastructure.
Despite its challenges, hydrogen as a fuel source not only for vehicles but more general applications is extremely exciting. Similar to the early stages of electric vehicle technology, available refueling infrastructure will have to be developed for hydrogen vehicles a feasible option for the masses. Additionally, the cost will have to be reduced for HCEVs and HICEVs to be a practical choice for average citizens. However, should the necessary investment come from the government and private industry hydrogen-powered vehicles could be the next evolution for low-emission transport.
Did you catch the full alternative vehicle fuels series? Click here for our kick off blog or the whole series.
Written by Nicholas Cheyne, Public Policy Intern
The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.