Renewable Hydrogen Energy: The Way of the Future?
We are amidst a transition toward to substantial amounts of renewable energy like solar, wind, geothermal, and biomass. But where and how does hydrogen fit? Do energy futures involve hydrogen, a relatively pollution-free fuel (when burned) that many see as viable?
Hydrogen is an energy carrier that can be produced from fossil and renewable sources. It can be used in engines or fuel cells with almost no climate effects. Hydrogen can decarbonize heating, lower power plant emissions, and use excess renewable generation. Existing natural gas infrastructure could theoretically be retrofitted to transport hydrogen.
Hydrogen has the highest energy content of any fuel used today other than nuclear. Presently, though, hydrogen production is energy-intensive and emits carbon dioxide (CO2). Brown hydrogen is created by transforming coal to syngas with hydrogen as a by-product. The CO2 that is emitted offsets the greenhouse gas benefits. Grey hydrogen, the most common type, comes from natural gas via a process known as steam reforming which also emits CO2, whereas Blue hydrogen combines reforming with captured CO2 that isolates it from the atmosphere. Green hydrogen uses renewable energy to create hydrogen fuel. For example, water electrolysis (which separates hydrogen from water), requires a lot of energy and is expensive. For us to realize the potential of hydrogen, we need to figure out environmentally and socially benign ways to inexpensively produce it.
Energy storage is a major challenge for the energy the sector. Batteries have improved but lack the charge-discharge characteristics for grid-scale storage and long‑duration energy storage. Hydrogen could be useful because it can function as an energy carrier and store energy for long periods. Its energy density when compressed is higher than that of lithium‑ion batteries.
Hydrogen may be most effectively integrated into transportation. Hydrogen fuel cell cars would reduce pollution because, like battery electric vehicles, the vehicles do not emit pollution. Some cars use this technology and have performance at least as good as many battery‑powered cars. In larger vehicles (e.g., buses, airplanes), research is investigating the use of hydrogen. Hydrogen can also be converted into fuels (e.g., synthetic methane, methanol, ammonia) that have potential transportation uses.
Given this potential, many at Ohio State are researching hydrogen. The Center for Automotive Research has been investigating hydrogen fuel cells. Patrice Hamel (molecular genetics) is leveraging a SI Seed Grant to investigate artificial metalloenzymes for hydrogen production in biological systems. Hannah Shafaat (chemistry and biochemistry, CBC) has developed an artificial enzyme for electrocatalytic and solution-phase proton reduction to hydrogen gas. A single-molecule photocatalyst has been developed by Claudia Turro (CBC) to produce H2 using low-energy light. Umit Ozkan (chemical and biomolecular engineering) has developed catalysts to improved hydrogen production during steam reforming. And despite being neglected as an energy source for decades, Tom Darrah and team from the earth sciences and the Global Water Institute, have developed an exploration strategy that has been successful in finding natural hydrogen occurrences in the subsurface. These and other types of research are complemented by expertise across the engineering, physical, social, policy, law, business, and other areas that are applicable to hydrogen as a topic of study.
It is also noteworthy that Ohio State’s energy partner, ENGIE, established a Hydrogen Business Unit that addresses the whole hydrogen value chain. And Ohio State has articulated a goal of converting the new combined heat and power plant to one day run on hydrogen, which would be sourced from environmentally and socially benign supply chains.
Can we get to a hydrogen world? We hope so.
by SI Sustainable Energy Co-Leads Dave Cole and Jeff Bielicki
