Offshore wind turbines offer path to clean hydrogen production | News

NREL Scientists Identify Promising Sites Off U.S. Coast for Technology Installation

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Using electricity generated by offshore wind turbines as one method to split water to produce clean hydrogen could make economic sense, particularly along the U.S. Atlantic coast and in the Gulf of Mexico, according to researchers at the National Renewable Energy Laboratory (NREL).

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

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 the location of production. Policy incentives may also play a role. Hydrogen can be produced using an electrolyzer, which splits water—consisting of two hydrogen atoms and one oxygen—into its component parts. The electrolyzer, powered by a renewable energy source, produces what is known as clean hydrogen. Through its
Hydrogen shot The DOE initiative 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, carbon-intensive hydrogen production methods.

“Both offshore wind and clean hydrogen are rapidly evolving technologies that, when combined, have the potential to generate and store large amounts of renewable energy and decarbonize hard-to-electrify sectors,” said Kaitlin Brunik, a hybrid systems research engineer at NREL and lead author of the new paper. “Continued investment and research in system- and plant-level design and optimization can spur further technological advances and cost reductions for these systems.”

Co-authors at NREL include Jared Thomas, Caitlyn Clark, Patrick Duffy, Matthew Kotarbinski, Jamie Kee, Elenya Grant, Genevieve Starke, Nick Riccobono, Masha Koleva, Evan Reznicek, and Jennifer King.

This paper describes the use of case-study simulations to analyze the techno-economics of producing hydrogen from offshore wind in 2025, 2030, and 2035. NREL researchers evaluated two scenarios based on offshore wind-powered electrolysis and identified four representative coastal areas for hybrid wind-hydrogen facilities. Depending on the water depths at the sites studied, the researchers considered whether the turbines would float or be anchored 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 but rather represents policy based on preliminary assumptions made before the publication of the proposed tax credit regulations.

In the first scenario, an offshore wind farm generated electricity that was transmitted via high-voltage cables to a site on land. There, an electrolyzer produced 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 by pipeline to shore for storage. The researchers noted that the technical feasibility of this scenario is less established.

“Moving the electrolyzer to an offshore platform for mass energy production presents a new challenge,” Brunik said. “To fully leverage the electricity generated by offshore wind farms for hydrogen production, large electrolyzers are needed, as well as ancillary equipment for water treatment, hydrogen storage and transport.” Offshore renewable hydrogen production remains uncharted territory, requiring innovative configurations to integrate all the necessary equipment into a wind farm for gigawatt-scale operations.

In addition to the technological design of these systems, the researchers considered where it would be best to place a wind-hydrogen system at sea. They looked at shallower sites in the Gulf of Mexico and New York Bay, where the turbines could be attached to the ocean floor, had abundant wind resources and were located near at least one of the DOE Regional Clean Hydrogen Centers that will connect hydrogen producers and consumers. They also explored 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 shore in underground pipes, rock caverns or salt caves.

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 the New York Bay due to greater wind capacity. The Gulf of Mexico had the second lowest value. The choice of where to store the hydrogen significantly affects the cost, with a 20% to 30% decrease in LCOH calculated based on cavern use. Projected policy incentives are also a factor in further cost reductions. This study showed 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.

Funding for the research came from the Department of Energy’s Wind Energy Technology Office and the Hydrogen and Fuel Cell Technologies Office.