Winding up offshore: Dominion’s project still on track in the Atlantic
By SEAN SUBLETTE
Wind turbines are among the technologies driving the development of renewable energy on a large scale, with the goal of reducing greenhouse gas emissions from fossil fuel power plants and slowing down planetary warming.
Onshore turbines are already common from Texas to Iowa, as winds are reliable on the Plains throughout most of the year.
That’s generally not the case in Virginia and the Middle Atlantic states, especially during the doldrums of July and August. But several miles offshore, it’s a different story, which makes wind turbines more practical.
Offshore wind has already scaled up quickly in Western Europe, and appears to be on the verge of rapid growth on this side of the Atlantic. But for the moment, there’s not much.
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A small group of five offshore wind turbines operated by the Danish firm Orsted has been generating power in the state waters off Rhode Island since 2016. Dominion Energy has been operating two wind turbines about 27 miles east of Virginia Beach since 2020.
Dominion appears poised to scale up offshore wind dramatically. The two turbines it currently operates are the pilot structures involved in its Coastal Virginia Offshore Wind project, and the turbines have performed well so far.
As a result, Dominion is continuing its plans to go big, with 176 new turbines extending outward an additional 15 miles by the end of 2026. This is roughly one for each square mile in the area it is leasing from the federal government over the next 30 years.
We went to take a look at the pilot turbines, as new technologies often come with questions. Some are more basic than others.
How do they make electricity?
Electricity is generated by spinning a metal coil around a magnet. Or vice versa. This process, called induction, was discovered nearly 200 years ago. In this case, wind turns the blades (the turbine), which spins a generator inside of the structure, producing electricity.
How big are they?
When a blade is at its highest point, the pilot turbines are 620 feet above the water line. For reference, the Washington Monument is 555 feet tall, and the James Monroe Building in downtown Richmond is 449 feet tall. Each blade is about 250 feet long.
The steel foundation of each turbine extends into the sea floor, and the distance between the ocean surface and the blades at their lowest point varies between 85 and 110 feet.
The new series of commercial turbines will be 30% larger, measuring 837 feet above the ocean surface with blades of 354 feet — about the length of a football field.
How much electricity will they make?
At peak output, one of the new turbines will be able to power 3,500 homes, with one revolution of the blades generating enough electricity to power one home for one day.
Once complete, the full series of turbines would produce enough electricity for 660,000 homes at peak, or about 25% of the household demand in Dominion’s service area — equivalent to 2.6 gigawatts (2.6 billion watts) of power.
How will the power get onshore?
Power from the turbines is sent downward through the center of each structure and into cables beneath the ocean floor. The cables are connected to each other remaining underground and run toward three offshore substations. From there, the substations send the power back to shore via special underground export cables.
Dominion proposes bringing the underwater cables onshore at the State Military Reservation in Virginia Beach, between the resort area and Sandbridge. The cables would continue underground until reaching Dominion’s new Harpers switching station on the edge of Oceana Naval Air Station.
From there, the power lines would transition to overhead lines and continue to Dominion’s existing Fentress substation near the Great Bridge section of Chesapeake, where they would join the rest of the high-voltage grid.
The Virginia State Corporation Commission plans to evaluate Dominion’s proposed onshore routing of the lines, with a decision expected later this year.
Has there been any environmental review?
A draft of the environmental impact statement is expected this summer from the lead federal agency, the Bureau of Ocean Energy Management. After a period of public comments, its final decision is expected in June 2023.
If the commercial project moves forward as Dominion plans, additional federal agencies — like the Environmental Protection Agency, the U.S. Fish and Wildlife Service and the Army Corps of Engineers — would issue their corresponding permits within 90 days of the BOEM decision.
What if there’s a hurricane?
In case of very high winds, like a hurricane, the turbines have been designed to feather, meaning they would rotate so that less of the blades’ surface area would be in contact with the wind. The turbine itself would also rotate to minimize force on it.
How fast is this all going to happen?
If the permitting and review is done on time, onshore preparations and manufacturing would start in the fall of 2023, with offshore construction beginning the following spring.
The foundations for the turbines will need to be installed between May 1 and Oct. 31 to avoid migration season of the North Atlantic right whale, which has been on the endangered species list since 1970. Dominion will likely need two seasons for the installations, meaning the foundations will not be ready for the turbines until 2025.
Work above the water can go on year-round. As a result, installation of the physical turbines is planned to start in August 2025, with completion by the end of 2026.
Will they be visible from the beach?
Generally not. But under the right conditions, some will be visible from the taller properties along the Virginia Beach Oceanfront.
How much will this cost customers?
Dominion is spending $9.8 billion to construct and commission the project. There will be variations, but it expects the net cost to be $4 a month to a typical residential customer.
But any direct costs to the customers must be approved by the SCC. With no fuel necessary to power the turbines, Dominion expects to save at least $3 billion in the first 10 years.
How long will they last?
Dominion plans for at least 30 years. It will track the performance and specifications of the equipment, optimistic it can go beyond the initial 30 years.
Got more questions? Email me.
Facebook: Sean Sublette, Meteorologist