October 18, 2022 — “With the amount of megawatts that we anticipate [from offshore wind] over the next decade, we need to be thinking in terms of optimizing how we are sending that electricity to where it’s needed,” says Paula García, senior energy analyst at the Union of Concerned Scientists. “And that’s one of the pieces of the equation that I think is changing the conversation right now.”
What García is describing is the growing consensus among federal and state leaders, industry experts, and environmentalists that the U.S. should build an offshore transmission grid.
Power strips for the ocean
The idea is fairly straightforward. Rather than every individual wind farm running a cable to land, they could plug into a network of high-capacity subsea power lines that come to shore in strategic places. There are many different ways this so-called “ocean grid” could be configured, but instead of “extension cords,” think of “linked power strips.”
An ocean grid wouldn’t entirely alleviate the need for onshore upgrades, but it would reduce what’s needed. It would also require putting fewer cables in the ocean, which means fewer potential environmental impacts and conflicts with fishermen. And, experts say, building it could help boost electric reliability for all coastal states.
Offshore transmission isn’t necessarily a new idea. A little over a decade ago, Google got involved in a $5 billion effort to build an “offshore backbone” to link future mid-Atlantic wind projects. At the time, the prospects for U.S. offshore wind looked promising, but as those fizzled, so too did the backbone plan.
Since then, the idea has surfaced from time to time among industry experts, but it’s really only in the last few years that the concept has started gaining traction in the U.S.
Currently, the U.S. Department of Energy and the Bureau of Ocean Energy Management are assessing various offshore transmission technologies and looking at what some northern European countries are doing. They’ve also held public meetings to help inform the Atlantic Offshore Wind Transmission Study report they plan to issue next year.
Work is happening at the state and regional levels too. New Jersey is considering building its own offshore transmission network, and New York has taken the step of mandating that all offshore wind projects be “mesh ready,” meaning built with the capacity to connect to each other offshore.
Here in New England, the states are also looking to move away from the project-by-project approach and toward a planned regional “paradigm.” To this end, five out of the six states recently issued a request for information about how they can take advantage of federal dollars to plan and build some sort of offshore transmission system.
“We’ve really reached a tipping point where I think the benefits and the logic of shifting to an offshore grid are increasingly understood and agreed upon,” says Peter Shattuck, New England president for Anbaric, a Massachusetts-based company that specializes in building transmission for renewable energy.
With only two large offshore wind projects fully approved, and many more in various stages of planning, “we’ve got a natural opportunity now to focus on building out the ocean grid,” he says.