US NREL: Offshore Wind Turbines Offer Path to Clean Hydrogen Production

Scientists at the US National Renewable Energy Laboratory (NREL) have found that using electricity generated by offshore wind turbines to split water and produce clean hydrogen could be cost-effective, particularly along the US Atlantic coast and in the Gulf of Mexico.

According to the researchers’ findings, published in “Potential for Large-Scale Deployment of Offshore Wind-Hydrogen Systems in the United States,” which appeared in the Journal of Physics: Conference Series, the economics work best in regions where the water is not as deep and the wind is strong.

NREL said the ability to produce hydrogen at a cost approaching the U.S. Department of Energy’s (DOE) goal for low-cost, clean hydrogen depends largely on both the technology used and where it is produced, adding that anticipated policy incentives could also play a role.

“Hydrogen can be produced using an electrolyzer that splits water—which is made up of two hydrogen atoms and one oxygen atom—into its component parts. The electrolyzer, powered by a renewable energy source, produces what is known as clean hydrogen. Through its Hydrogen Shot initiative, DOE is leading an effort to reduce the cost of clean hydrogen to $1 per kilogram by 2031. Reaching $2 per kilogram could make it cost-competitive in some applications with conventional, high-carbon hydrogen production methods,” the researchers said.

Kaitlin Brunik, A research engineer at NREL and lead author of the new paper stated: “Both offshore wind and clean hydrogen are rapidly evolving technologies and, when combined, have the potential to generate and store large amounts of renewable energy and decarbonize hard-to-electrify sectors. Further investment and research into system and plant-level design and optimization could drive further technological advances and cost reductions for these systems.”

This paper describes the application of case simulations to the techno-economic analysis of hydrogen production from offshore wind energy in 2025, 2030 and 2035.

The researchers evaluated two scenarios based on offshore wind-powered electrolysis and identified four representative coastal areas for hybrid wind-hydrogen installations. Depending on the water depths at the sites studied, they considered whether the turbines would float on the water or be attached to the ocean floor. The study suggests that by 2030, a combination of factors, including policy incentives and fixed-bottom offshore wind with onshore electrolysis, could enable hydrogen production for less than $2 per kilogram. The analysis does not provide policy guidance, according to NREL, but rather represents policy based on preliminary assumptions made before the proposed tax credit regulations were issued.

NRL revealed that in the first scenario, an offshore wind farm generated electricity that was transmitted via high-voltage cables to a site on land, where an electrolyser would produce hydrogen from fresh water. This represented the conventional approach of combining offshore wind with onshore electrolysis.

In the second scenario, hydrogen was separated from desalinated seawater at an offshore wind farm site, requiring more infrastructure in the ocean to accommodate the additional equipment. The hydrogen was then transported to shore via pipelines for storage. The technical feasibility of this scenario is less established, according to the researchers.

Brunik said: “Moving the electrolyzer to an offshore platform for mass energy production poses a new challenge. To fully exploit the electricity generated by offshore wind farms for hydrogen production, large electrolyzers are needed, as well as supporting equipment for water treatment, hydrogen storage and transport.”

In addition to the technological design of these systems, the researchers considered where it would be best to site an offshore wind-hydrogen system. They looked at shallower sites in the Gulf of Mexico and New York Bay, where turbines could be attached to the ocean floor, had abundant wind resources and were near at least one of DOE’s Regional Clean Hydrogen Hubs, which will connect hydrogen producers and consumers. They also examined sites with much deeper water off the coast of Northern California and in the Gulf of Maine, where turbines would have to be installed on floating platforms. The hydrogen would be stored on land in underground pipes, rock caverns or salt caves, NREL noted.

The analysis predicted that the levelized cost of hydrogen (LCOH), which includes the entire wind system, electricity transmission and hydrogen system, could be lowest in New York Bay because of the greater wind power. The Gulf of Mexico had the second lowest.

NREL concluded: “The choice of hydrogen storage site significantly impacts costs, with LCOH based on cavern usage being reduced by 20% to 30%. Anticipated policy incentives are also a factor in further cost reductions. This study has shown promising indicators of what large-scale deployment of offshore wind hydrogen could look like, and will continue to be an area of ​​interest as new and better technologies continue to be developed in this area.”

It is worth noting that the research was funded by the Wind Energy Technology Office and the Hydrogen and Fuel Cell Technologies Office of the Department of Energy.

To learn more about hydrogen in the U.S., click here.