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The next step in harnessing clean wind energy could be building electrical grids in the ocean


Offshore wind farms are poised to deliver a lot of carbon-free electricity, but the electrical grid in many coastal areas can't handle that load. As WBUR's Miriam Wasser reports, one solution may be to lay an electrical grid in the ocean.

MIRIAM WASSER, BYLINE: Brayton Point, in southeast Massachusetts, was once home to New England's largest coal plant. Now Lawrence Mott with offshore wind developer Mayflower Wind says this humming electrical equipment is about to get a second, greener life.

LAWRENCE MOTT: With the coal plant being decommissioned, we're taking advantage of that same infrastructure to connect the offshore wind power.

WASSER: It will all start 30 miles out in the ocean where later this decade, powerful winds will spin turbines to generate electricity. The energy will travel through cables buried about six feet beneath the ocean floor and land here at Brayton Point.

MOTT: And from there, it goes into the public's grid system.

WASSER: To date, all offshore wind projects on the East Coast are designed to work like this. Wind developers will essentially run a high-voltage extension cord from their wind farms to open substations on land, usually whatever's closest. This is fine for now, but soon, there will be two big problems. First, developers could run out of places like Brayton Point to plug into. And second, the onshore grid just isn't set up to accept so much electricity.

ERIC HINES: All of us have had moments where we plugged in too many things to one socket in the house and we blew a fuse, right?

WASSER: Eric Hines leads the offshore wind energy graduate program at Tufts University. He says to think about transmission lines like a system of arteries, veins and capillaries. Bigger lines can carry more power.

HINES: When you plug into the grid, you want to plug in to the arteries, right? If you get a blood transfusion, you don't take it through your finger where they try to pump blood through your capillaries. You know, you really have to find the right points into the grid.

WASSER: Many of the first few offshore wind projects will plug in to Cape Cod and parts of Long Island. But the grid in those areas is full of capillaries. Upgrading to arteries will cost billions of dollars. And that's if it can even get permitted.

HINES: It would be ideal if we could create a system that the offshore wind farms could connect into, as opposed to every project trying to find its own landing point, its own connection into the land-based grid.

WASSER: What Hines is talking about is a coordinated transmission system of arteries in the ocean that will bring power directly to Boston, New York City and other population centers along the East Coast. Instead of extension cords, think of linked power strips. This so-called ocean grid isn't necessarily a new idea, but it's gained traction in the last few years as offshore wind finally looks like it's going to take off in the U.S.

PETER SHATTUCK: And so we've got a natural opportunity now to focus on building out the ocean grid.

WASSER: Peter Shattuck is the president of Anbaric, a Boston-based company that specializes in building transmission infrastructure for renewable energy. He says there could be one central backbone running from Maine to Florida that all the projects plug into or something that's more decentralized. But whatever the design, experts say building it will be cheaper and probably faster than only trying to upgrade onshore infrastructure. It likely would be better for the environment and fishing industry, too, since it would require fewer cables under the ocean floor. Plus, Shattuck says, connecting all of the wind farms offshore would be good for grid reliability.

SHATTUCK: If any one of the lines goes down, you still have all the other ones.

WASSER: Still, there are a lot of big unknowns about an offshore grid. Who builds it? Who pays for it? Who owns it? The federal government is looking at some of these questions as part of a two-year study for the Atlantic Coast. And in the meantime, some states are moving forward independently. New Jersey is the farthest ahead. It recently approved a coordinated transmission plan for its next few offshore wind projects. New York is requiring that all new projects use compatible cable technology. And New England state leaders are looking into how they can use federal infrastructure dollars to build offshore transmission for the region. Back at Brayton Point, Lawrence Mott with Mayflower Wind says he's optimistic about all of this.

MOTT: The major benefit of building offshore is that it's new. It's fresh. You can start with a clean slate on how you want to design it. And you can use the latest technology.

WASSER: Other wind developers also say they're open to the idea of an ocean grid, but they're not banking on it coming together anytime soon. They're on the line to deliver a lot of power by specific dates. So for the time being, they're planning to run an extension cords to shore. For NPR News, I'm Miriam Wasser in Somerset, Mass. Transcript provided by NPR, Copyright NPR.

Miriam Wasser - WBUR