Offshore wind could supply up to 20% of the US Atlantic coast energy needs – study

Wind turbines at the Block Island Wind Farm, off the coast of Rhode Island. (Image by Suzanne Tegen, courtesy of NREL).

As much as 20% of regional power needs along the US Atlantic coast could be served by offshore wind farms by 2050, according to research by the Department of Energy’s National Renewable Energy Laboratory (NREL).

In a recent paper published in the journal Nature Energy, the lab’s experts modelled the deployment of offshore wind in new depth and detail. They considered a diversity of scenarios to more clearly understand how a single renewable resource can affect the country’s target of decarbonizing the power system.

The researchers found offshore wind could generate as much as 8% of the nation’s electricity by 2050, but that deployment could range widely, from 30 to 250 gigawatts, depending on how a variety of factors related to the power system evolve over the coming decades.

To reach these conclusions, they developed a capacity expansion model and found that high levels of offshore wind deployment are most likely in scenarios where there is a combination of stringent decarbonization policies, low technology costs, fewer siting options for onshore renewables, and limited interregional transmission. For example, the study’s core scenario considers strict zoning regulations for onshore wind and solar panels that expand offshore wind’s market potential.

“We represent siting, energy supply, and transmission at a high spatial and temporal resolution,” Philipp Beiter, lead author of the paper, said in a media statement. “This allows us to explore a range of decarbonization pathways and offshore wind’s future role.” 

By taking into account various conditions, the researchers were able to more fully consider the growing number and severity of trade-offs that arise with decarbonization scenarios. The results of the analysis illustrate how limitations affect deployment and could lead to different conclusions.

Multiple possibilities

In many of the scenarios studied, offshore wind deployment is limited to the level defined by current state commitments, with solar photovoltaics and onshore wind meeting most new electricity demand through 2050.

The amount of energy from nuclear, hydropower and fossil fuels is relatively constant across the scenarios, with fossil generation limited by an emissions cap, unless carbon capture and sequestration technology is available and economically viable. Under the study’s core scenario with high load growth and electrification, offshore wind accounts for 133 gigawatts by 2050. By comparison, the installed land-based wind farms scattered across the United States today total about 141 gigawatts and produce 10% of the country’s electricity.

“For newer generation sources like offshore wind, it is particularly important to identify the types of conditions when they may be viable in different parts of the country,” study co-author Trieu Mai said.

In the United States, only two small offshore wind plants off the coasts of Rhode Island and Virginia are currently in operation. Still, many more are proposed along the Atlantic and Pacific coasts. The first US large-scale offshore wind farm—with a planned installed capacity of 800 megawatts—could start generating power as early as this fall off the coast of Massachusetts.

In the researchers’ view, the high uncertainty about future decarbonization pathways also raises the need for greater coordination between local, state, and federal authorities in the power sector and offshore wind infrastructure planning.

“Our study highlights several limitations that—if not addressed—can yield starkly different futures for US offshore wind,” Beiter noted. “That said, many inherent limitations of energy system modelling remain and require careful interpretation and presentation.”