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As the momentum for moving to a zero-carbon energy landscape by 2050 continues to grow, the future looks increasingly promising for renewable electricity produced by ever-larger wind turbines and more efficient solar panels. This is complemented by announced internal combustion engine (ICE) vehicle phaseouts in favor of battery electric powertrains — a transition supported by automaker investments globally. Much of that added electrical capacity will have an outlet in vehicles, it seems.
In the last nine to 12 months, another technology has been pushing hard to earn the same front-runner status as wind and solar: propelling future energy needs with clean-burning, emissions-free green hydrogen. The term green refers to hydrogen produced via electrolysis (separating water into hydrogen and oxygen using electricity from renewable resources) in large electrolyzers.
Today, the production of green hydrogen is rather nascent — most hydrogen currently produced is either gray, produced via steam reformation of methane (natural gas), or brown, via gasification of coal and practiced mainly in China. Neither gray nor brown hydrogen is carbon-free. An emerging, and highly touted intermediate technology is blue hydrogen, which pairs steam reformation of methane with carbon capture, utilization and storage (CCUS), greatly reducing — but not eliminating — the carbon footprint. Today’s demand for hydrogen is primarily in petroleum refining, plus ammonia and methanol production, with emerging use in steel production and industrial heating.
Those riding the hydrogen bandwagon are hoping for a massive increase in production via blue, and more importantly, green technologies — first, to replace gray and brown hydrogen, then to serve as a major fuel for transportation and for commercial and residential heating, replacing natural gas. In July 2020, the U.S. Department of Energy (DOE) announced approximately $64 million in funding for 18 projects under the H2@Scale vision, including work in less costly electrolyzers, fuel cells for heavy-duty applications and lower-cost, high-strength carbon fiber for pressurized hydrogen storage and delivery. Also, in 2020, the European Union (EU) announced plans to expand electrolyzer capacity from 60 megawatts (MW) to more than 40 gigiwatts (GW) by 2030, all powered by electricity from renewable resources, which will have to be expanded at great cost as well, boosting demand for composites in the wind market in the process.
The best opportunity for the use of hydrogen appears to be in long-distance transportation.
Headway is also being made in the aerospace and automotive industries. CompositesWorld readers surely noticed that Airbus (Toulouse, France) announced in September 2020 three emissions-free aircraft designs under the ZEROe banner, powered by liquid hydrogen combustion and slated for entry into service by 2035. Further, a number of heavy truck makers are fielding prototype fuel cell-based rigs that will run on high pressure gaseous hydrogen. If these programs are commercialized, they will require many tons of carbon fiber for hydrogen tanks and develop opportunities for composites use in proton exchange membrane (PEM) fuel cell technologies as well.
So, is this all just wishful thinking (hope) or bravado (hype) now that decarbonization is front and center in the global discussion? In June 2017, my column titled “Where are they now?” looked at the fuel cell craze of the late 1990s and early 2000s, when high fuel prices were important drivers. Troubled by high costs and other technical issues, fuel cells fell to niche status when petroleum prices abated. Early in 2021, there were still fewer than 40,000 fuel cell electric vehicles (FCEVs) on the road worldwide, with the largest fleets at roughly 9,000 in California and Korea.
The ultimate decider of hydrogen’s fate will be economics. What is the lowest cost technology for delivering carbon-free energy? The cost of green hydrogen depends heavily on scaling electrolyzer capacity and the delivered cost of renewable electricity to run that capacity. Forecasts show wind and solar energy costs falling as low as 1-2 cents per kilowatt-hour by 2050, which helps green hydrogen costs, but with electricity that cheap, why not use it directly for heating and powering transportation? Battery costs and densities are forecast to improve significantly by 2030, and major OEMs are investing heavily in BEV portfolios, so it seems unlikely that hydrogen will play a major role in powering light vehicles. There will be opportunities to convert excess renewable electricity to hydrogen when the wind blows strong and the sun is shining. This hydrogen can be stored, perhaps in salt caverns, or perhaps in carbon fiber pressure vessels, and converted back to electricity when needed.
The best opportunity for the use of hydrogen appears to be in long-distance transportation. Heavy-truck fleets likely will eventually use a combination of battery and fuel cell powertrains (using compressed hydrogen in carbon fiber tanks), whereas passenger aircraft flying more than 1000 nautical miles will find liquid hydrogen a much lighter solution than batteries. Economics also favor hydrogen for marine transport, up to and including cargo ships.
Hope or hype? Perhaps a bit of both, and composites stand to fare well, however the hydrogen economy evolves.
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