Electrolysis is the method of splitting water into hydrogen and oxygen using electricity. When powered by renewables, such as wind and solar, it offers one pathway to producing green hydrogen with zero or minimal carbon dioxide (CO2) emissions. Currently, this production pathway is energy-intensive and more expensive than traditional production methods that utilize fossil fuel feedstocks, such as natural gas. In the short term, carbon capture and storage can be deployed with steam methane reforming to reduce CO2 emissions via blue hydrogen. However, in the long term, deep carbonization via green hydrogen will depend on a variety of factors, such as technological advancements, market development and investment, and economies of scale, in order to reduce the cost of producing and operating electrolyzers.
The DOE’s Vision for Affordable and Abundant Green Hydrogen
Last week, the U.S. Department of Energy (DOE) released Hydrogen Shot™: Water Electrolysis Technology Assessment, showcasing pathways to reducing the cost of producing green hydrogen using electrolysis. At different technology readiness levels, the report documents the current state of five different electrolyzer technologies:
- Proton exchange membranes (PEMs)
- Liquid alkaline (LA)
- Alkaline exchange membranes (AEMs)
- Oxide-ion-conducting solid-oxide electrolyzer cells (O-SOECs)
- Proton-conducting solid-oxide electrolyzer cells (P-SOECs)
As the second of three assessments, the report focuses on today’s electrolyzer status and research, development, and demonstration potential to achieve the Hydrogen Shot target of $1/kilogram of clean hydrogen by 2031.
The first report, Hydrogen Shot Technology Assessment: Thermal Conversion Approaches, examined clean hydrogen production processes that use heat to convert fossil and/or waste feedstocks with carbon capture and sequestration, while the third and final report will assess advanced clean hydrogen production pathways, including photoelectrochemical and thermochemical processes that use sunlight to split water without the use of electricity and biological processes that convert biomass or waste streams into hydrogen.
These reports come at a critical time for clean and renewable hydrogen, as a growing number of countries and organizations race against the clock to find innovative solutions for reducing the cost of electrolysis production.
Breakthroughs in Solar Hydrogen Production from Japan
For example, scientists in Japan recently released a Frontiers in Science article on advancements and trends of sunlight-driven water splitting using photocatalysts and particulate semiconductors. This advanced clean hydrogen production pathway represents a promising alternative to other green hydrogen production methods that rely on high electricity inputs.
The study also showcased the scientists’ successful solar hydrogen production pilot project with near-perfect conversion yield. In operation for three years, this 100m2 photocatalyst array system split water with high solar-to-fuel energy conversion efficiency, thereby demonstrating the feasibility of scaling large solar hydrogen production using photocatalysts safely without reducing their efficiency.
Significant Growth of Electrolyzer Capacity
With industry and government projections of significant growth in demand for renewable hydrogen production via electrolysis, all of these electrolyzer technologies have the potential to scale and offer a diverse array of applications for green hydrogen across multiple sectors and end uses.
(Source: U.S. Energy Information Administration)
Achieving the DOE’s Hydrogen Shot goal will require continued industry and government innovation, strategic collaboration, and substantial investment towards technology advancements, manufacturing and economies of scale, and clean hydrogen integration to unlock clean, affordable, and abundant hydrogen.
