Winds of Change

Building an offshore wind farm is a massive undertaking. Engineers began construction of the Block Island Wind Farm in late 2014. Parts traveled to Rhode Island by barge from Louisiana and Europe.

Workers drove four steel legs into the seafloor at the site of each turbine. On top of each set of legs, they built a steel platform. A giant crane lifted the turbine towers and generators onto the platforms. Finally workers attached the propeller-like blades. Each measures 73 meters (240 feet) long—more than the wingspan of a passenger plane—and weighs 26 tons.

Turbine blades have a slightly curved shape. That causes areas of low and high pressure to form on either side of a blade as wind flows around it. The pressure difference creates an upward force called lift that spins the blades. As they move, the blades turn a generator that creates electricity. Cables on the seafloor transmit the power back to shore for people to use (see Ocean Wind Power).

Building an offshore wind farm is a huge task. Engineers began to build the Block Island Wind Farm in late 2014. Barges carried parts to Rhode Island from Louisiana and Europe.

Workers drove four steel legs into the seafloor at the site of each turbine. They built a steel platform on top of each set of legs. A giant crane lifted the turbine towers and generators onto the platforms. Then workers attached the propeller-like blades. Each weighs 26 tons and measures 73 meters (240 feet) long. That’s more than the wingspan of a passenger plane.

Turbine blades have a slightly curved shape. Wind flows around the blade, and the shape causes areas of low and high pressure to form on either side. The pressure difference creates an upward force called lift. This force spins the blades. The moving blades turn a generator, which creates electricity. Wires on the seafloor send the power back to shore for people to use (see Ocean Wind Power).

Before the completion of the Block Island Wind Farm, all wind power in the U.S. came from land-based turbines. They generate only a small percentage of our electricity (see Energy in the U.S.).

Wind farms on land are easier and cheaper to build than offshore wind projects. The Block Island Wind Farm cost $300 million, more than three times as much as comparable land-based wind farms. But sea-based wind turbines have some advantages. Winds over the ocean are stronger and steadier than those on land. So offshore turbines are more efficient and reliable. An ocean wind farm needs fewer turbines than a land-based one to generate the same amount of electricity.

Before the Block Island Wind Farm was finished, all wind power in the U.S. came from turbines on land. They produce only a small part of our electricity (see Energy in the U.S.).

Wind farms on land are easier and cheaper to build than offshore wind projects. The Block Island Wind Farm cost $300 million. That’s more than three times as much as similar land-based wind farms. But sea-based wind turbines have some benefits. Winds over the ocean are stronger and steadier than those on land. So offshore turbines are more efficient and dependable. An ocean wind farm needs fewer turbines to make the same amount of electricity as a land-based wind farm.

Still, the U.S. has been slow to adopt offshore wind. About 90 percent of the world’s ocean wind farms are in European waters. One reason is that some U.S. coastal residents have opposed offshore wind projects, in part because of their potential to obstruct scenic ocean views. Such objections recently led developers to scrap a $2.5 billion proposal to build 130 turbines off the coast of Massachusetts after more than 15 years of planning.

Early offshore wind farms in Europe faced similar concerns. But European governments were committed to expanding renewable energies and cutting air pollution. Government investments helped the offshore wind industry there get started more than 25 years ago.

Warren Mabee, a renewable energy expert at Queen’s University in Ontario, Canada, says that in the U.S., Block Island was an easier sell partly because of its location. Fewer homes there overlook the turbines. “It is possible to minimize the visual impact of these sites with clever planning,” says Mabee.

But the U.S. has been slow to take up offshore wind. About 90 percent of the world’s ocean wind farms are in European waters. One reason is that some people on U.S. coasts oppose offshore wind projects. Part of their concern is that turbines could block scenic ocean views. Not long ago, such arguments led developers to scrap an idea to build 130 turbines off the coast of Massachusetts. They had spent more than 15 years on the plan.

The first offshore wind farms in Europe faced similar concerns. But European governments made a choice to expand renewable energies and cut air pollution. Government investments helped the offshore wind industry get started there. That was more than 25 years ago.

Warren Mabee is a renewable energy expert at Queen’s University in Ontario, Canada. He says that in the U.S., Block Island’s location made it easier to accept. Fewer homes are near the turbines. “It is possible to minimize the visual impact of these sites with clever planning,” says Mabee.

Since the completion of the Block Island Wind Farm, offshore wind projects are now being planned for places like Maryland, Massachusetts, New Jersey, New York, and Virginia. Over the next 20 years, offshore wind growth along the east coast could generate enough energy to power more than 115 million households, some 75 percent of the projected U.S. population.

Growth like that could go a long way toward reducing U.S. dependence on fossil fuels. Scientists believe that gases emitted when people burn fossil fuels are the primary cause of climate change. Relying more on renewables for our energy needs could help address this global environmental issue.

A study by the ocean conservancy organization Oceana, for example, suggests that over the next two decades, wind farms along the east coast could generate more energy than all of the oil and gas that the U.S. could ever drill from the Atlantic Ocean. “Offshore wind can provide more energy than offshore oil, it doesn’t contribute to climate change, and it will never run out,” says Jacqueline Savitz, Oceana’s senior vice president for U.S. oceans. It’s no wonder the forecast for offshore wind energy is looking up.

The Block Island Wind Farm is complete, and more offshore wind projects are in the works. They’re being planned for places like Maryland, Massachusetts, New Jersey, New York, and Virginia. Offshore wind growth on the east coast could have a big effect. Over the next 20 years, it could produce enough energy for more than 115 million households. That’s 75 percent of the projected U.S. population.

That kind of growth could greatly lower the nation’s need for fossil fuels. Gases are released when people burn fossil fuels. Scientists believe that’s the main cause of climate change. Using more renewable energy could help address this global environmental problem.

For example, take a study by Oceana, an ocean conservancy organization. It figured how much energy wind farms along the east coast could produce over the next two decades. It would be more than the amount from all of the oil and gas that the U.S. could drill from the Atlantic Ocean. Jacqueline Savitz is Oceana’s senior vice president for U.S. oceans. She says, “Offshore wind can provide more energy than offshore oil, it doesn’t contribute to climate change, and it will never run out.” It’s no wonder the forecast for offshore wind energy is looking up.