Offshore Wind Farms See Promise in Platforms That Float

This is the second time we've seen this improvement on wind tested.  If adopted using platforms would make wind viable in almost all offshore locations.  It would improve safety as well.

The added flexibility, if not accompanied by a big increase in cost, would usher in large-scale installs around the islands and parts of Africa, assuming their grids could handle the jump in power.

Offshore Wind Farms See Promise in Platforms That Float

By DIANE CARDWEL

A 1/52-scale model of a floating wind turbine sits in a wind and wave simulator inside the facility of the Advanced Structures and Composites Center at the University of Maine in Orono. Credit Tristan Spinski for The New York Times

ORONO, Me. — The sun was beating down on the leafy campus of the University of Maine one afternoon last month. But inside a hangarlike laboratory, a miniature hurricane was raging.

Storm-force gales swept over a deep pool of water, churning waves that, at full scale on the ocean, would have been twice the size of those recorded during Hurricane Sandy in 2012.

Happily for the researchers, the equipment they were testing, a novel type of floating platform meant to support a wind turbine in open water, remained upright through the maelstrom.

True, it was only one fifty-second of the real-world scale. But it was a success as one of many experiments and projects underway worldwide in a similar quest. As clean-energy engineers seek to make offshore wind farms more financially, aesthetically and environmentally viable, they are turning to floating supports to enable wind turbines to move into deeper waters farther from the coast.

Right now, almost all offshore wind turbines require fixed platforms built into the seafloor. Floating turbines, with anchors, would mean new flexibility in where wind farms could be placed, with potentially less impact on marine life — and less opposition from the human neighbors on shore.

“Look,” exclaimed Habib Joseph Dagher, executive director of the university’s Advanced Structures and Composites Center here, pointing to a minuscule figure perched on the bobbing deck. “The water is just reaching his feet.” The Lilliputian plastic platform worker had weathered the storm.

The University of Maine testing is part of an elaborate physics experiment meant to simulate conditions that full-scale floating wind turbines could face at an installation being planned about 10 miles off the Maine coast in up to 360 feet of water near tiny Monhegan Island.

For nearly 18 months in 2013 and 2014, an operating version of the apparatus — one-eighth of scale — sat in the waters off Castine, Me., sending electricity to the grid. That proved the technology fundamentally worked and guided refinements to the design. Now, Dr. Dagher’s team is using the data collected at the lab to confirm the final form, a crucial next step in bringing the technology to market.

Conventional offshore wind developments, with foundations deep beneath the ocean floor, are increasingly common in Europe. But partly because of public opposition, fixed offshore turbines are just starting in the United States, with the first such farm set to begin operation by November near Rhode Island.

Meanwhile, energy companies, researchers and government officials are also proceeding with floating technologies adapted from deepwater oil and gas drilling rigs, which use tethers and anchors to moor platforms to the seabed. That could make deeper waters — like those off the Pacific Coast, around the Hawaiian islands and in the Great Lakes — accessible for wind-energy development.

Statoil, the Norwegian oil and gas giant, is already developing what could become the first commercial-scale floating wind farm, off the coast of Scotland.

Trident Winds, a company based in Seattle, is pursuing a federal lease to install about 100 turbines more than 30 miles out from Morro Bay on the central California coast.

A rendering of three fixed wind turbine platforms, left, and three floating platforms, right. Floating platforms could open deeper waters to wind energy development. Credit Josh Bauer/NREL — Department of Energy

And the Obama administration recently released an updated offshore wind strategy that identifies the floating structures as important in fighting climate change. More than half of the United States’ potentially capturable offshore wind capacity — more than what the entire nation can now produce — is in deeper waters, said José Zayas, who directs the Wind Energy Technologies Office at the federal Department of Energy. Mr. Zayas predicts that floating platforms may come to outnumber fixed-foundation installations.

The use of floating technologies, proponents say, could help overcome some obstacles that have deterred offshore wind farms.

Developers can locate the farms farther out at sea, where they would not be visible from land, and their anchoring mechanisms have a smaller, more flexible footprint than the embedded foundations of conventional wind turbines. That could result in less environmental disturbance and easier transportation and installation.

Cost is an obstacle that must be overcome, despite multimillion-dollar grants from the federal government. Floating farms are more expensive to build than land-based ones, and in the early going, at least, would cost more than fixed offshore installations.

Ocean wind power, moreover, has had trouble competing with other cheap sources of electricity, including large-scale solar, hydroelectric and natural gas.

Principle Power, a multinational company based in Emeryville, Calif., that planned to float five turbines near Oregon in a demonstration project with the help of as much as $47 million from the Department of Energy, could not secure a power purchase agreement because the projected cost of its electricity was considered too expensive.

It is now pursuing projects elsewhere in the United States and in France, Portugal, Japan and other European and Asian markets, said Joao Metelo, the company’s chief executive.

But advances in the designs are beginning to reduce costs, and there is potential for them to come below those of conventional offshore wind, energy executives say. Fixed-foundation turbines require highly specialized equipment, vessels and installation procedures. In addition, each must be customized to its location, said Irene Rummelhoff, executive vice president for new energy solutions at Statoil.

“With the floating concept, you can use the same turbine everywhere, so you can see the potential for mass production,” Ms. Rummelhoff said.

Various types of floating wind platforms are in the works, but two are closest to commercial availability. Statoil’s design, known as Hywind, attaches the turbine to a special buoy that uses a steel cylinder filled with water and rocks as ballast — a floating structure that extends more than 300 feet beneath the water’s surface.

Principle Power’s foundation, known as the WindFloat, sets the turbine atop one of three columns that are partly underwater and connected with a triangular frame.

The University of Maine’s prototype, part of a demonstration project called Aqua Ventus that is partly financed by the Department of Energy, is similar to the WindFloat. But Aqua Ventus fixes the turbine on a central concrete pier attached by spokes to three others, a design Dr. Dagher said would make it cheaper to produce. It floats because the concrete contains air.

“The beauty of this is, every 20 years — which is typically when the turbine reaches the end of its life — you can tow this back to shore, put a new turbine on and take it back,” he said.

The university researchers, who are working in partnership with private companies, have received about $22.7 million in grants from the Energy Department, which in May deemed the demonstration project eligible for as much as $39.9 million more for completion. Dr. Dagher said that if all went well, his team could have two full-scale turbines pumping electricity into the Maine grid in 2019 and larger commercial farms starting construction in the Gulf of Maine by the mid 2020s.

Although the project has attracted support throughout the state, it has stirred controversy on Monhegan. The island has a year-round population of about 70 that swells into the thousands over the summer, and its stark beauty has long made it an artists’ haven.

The turbines, though about 10 miles from the mainland, will sit less than three miles from Monhegan, interrupting pristine views and lobster fishing operations, opponents say.

Supporters point to the potential for cheaper electricity and better internet service through an underwater cable connection from the wind farm to the island. And the local electric company, which labored for years to build its own reliable, independent system, is continuing to work to bring renewable energy to the island.

Still, some residents remain wary of connecting to the Aqua Ventus farm because it is a test project with a potentially short life and many uncertainties. Some have even talked of suing to stop the project.

But with the federal grant, the project is moving ahead. And that, said Marian Chioffi, the bookkeeper of Monhegan’s electric company, has residents trying to reach consensus on how the island’s energy future should look and what economic gain the project should bring them. The project is required to demonstrate economic benefits for the state.

“Monhegan isn’t sure what benefit they wanted,’’ Ms. Chioffi said. “But if the project is going to go here, they want some sort of benefit out of it.”