Thursday, December 9

Floating Wind Turbines Could Open Vast Ocean Tracts For Renewable Energy | Environment


In the stormy waters of the North Sea, 15 miles off the coast of Aberdeenshire in Scotland, five floating offshore wind turbines stretch 574 feet (175 meters) above the water. The world’s first floating wind farm, a 30-megawatt facility managed by the Norwegian company Equinor, has only been in operation since 2017, but has already broken power production records in the UK.

While most offshore wind turbines are anchored to the ocean floor on fixed foundations, limiting them to depths of about 165 feet, floating turbines are tied to the seabed by mooring lines. These huge structures are assembled on land and carried out to sea in ships.

The ability to install turbines in deeper waters, where winds tend to be strongest, opens up huge amounts of ocean to generate renewable wind power – close to 80% of potential offshore wind energy is found in deeper waters. In addition, placing floating turbines much further from shore helps avoid conflict with those who oppose their use. impact on coastal views.

Floating offshore wind power is still in its early stages: only 80 megawatts out of a total of approximately 32 gigawatts (0.25%) of the installed offshore wind capacity is floating. But some experts say the relatively new technology could become an important part of the renewable energy mix, if it can overcome obstacles such as cost, design and opposition from the fishing industry.

The United States has traditionally lagged behind Europe when it comes to offshore wind, but that may be changing. Joe Biden has committed to building more than 30 GW of offshore wind by 2030. The Department of Energy says he has invested more than $ 100 million in research and development of floating offshore wind technology in an attempt to establish itself as a leader in the sector.

While the reliable winds and relatively shallow waters off the U.S. East Coast have made it a favorite target for offshore wind projects, such as the recently approved Vineyard Wind off the coast of Martha’s Vineyard, on the West waters are mostly too deep for fixed platform turbines. This is where the defenders wait for the floating wind to take off.

In May, the Biden administration and California Governor Gavin Newsom announced a plan to bring floating offshore wind power to California. They have identified two sites: an area of ​​nearly 400 square miles northwest of Morro Bay, which could host 380 floating wind turbines, and another further north of Humboldt Bay. Together, these projects could bring up to 4.6 GW of clean energy to the grid, enough to power 1.6 million homes.

“[The announcement] it was a real breakthrough, ”said Adam Stern, executive director of the Offshore Wind California trade association. “At a time when the effects of climate change are evident in California every day, in the form of wildfires and drought conditions,” he said, “offshore wind can provide clean and reliable electricity for millions of California residents.” .

the International Energy Agency estimates that for the world to stay on the path to carbon neutrality by 2050, it needs to add 390 GW of wind power (80 GW of which would be offshore) each year between 2030 and 2050.

This is a huge leap from current figures, especially for the offshore wind industry, which installed just over 6GW of new capacity in 2020. But wind power has been growing as costs fall and countries look to move away from fossil fuels to meet climate goals.

It is not clear how much the floating wind will influence. Countries including Norway, Portugal, South Korea and Japan are installing or planning floating wind projects, with more than 26GW of estimated capacity in the pipeline, based on an estimate.

“Without a doubt, wind is a big part of the solution to getting to zero,” said Michael Webber, an energy expert and professor of engineering at the University of Texas at Austin. But he thinks floating wind power is likely to take time to grow, and predicts that onshore wind and fixed-bottom offshore wind will dominate for the next decade.

Great obstacles certainly remain. The cost is significant. Floating offshore wind generation costs are roughly double those of fixed offshore wind, although they are expected to decline as technology advances and supply chains improve. Estimates from the National Renewable Energy Laboratory (NREL) research body suggest that floating turbine projects could achieve cost parity with their fixed-fund counterparts around 2030.

One drawback is the number of designs for anchoring the floating turbines, which some experts believe will make it difficult to cut costs.

Three floating wind turbine designs: mast, semi-submersible and tension leg platforms
Three of the main floating turbine designs include the mast buoy (left), semi-submersible (center), and tension leg platforms (right). Photograph: Joshua Bauer / NREL

There are three main designs. The mast buoy, the design of the Hywind floating turbines in Scotland, has a long, heavy cylindrical tube that extends downward from the turbine and below the ocean surface to balance it. Semi-submersible platforms, which are the most common for installed and planned projects, are modular and consist of floating cylindrical structures secured by mooring lines. The tension leg structure has a smaller platform anchored to the sea floor with taut mooring lines.

“I’ve lost count of how many concepts really exist,” said Po Wen Cheng, director of wind energy at the University of Stuttgart in Germany. “Ford didn’t make the car affordable to the broad masses by making 30 different types of cars; they just made a Model T. If we really want to cut cost, we can’t tolerate so many different concepts,” he said.

Parts of the fishing industry have also raised concerns that offshore wind could interfere with their equipment, obstruct fishing areas and negatively affect their livelihoods.

Semi-submersible floating wind turbines off the coast of Viana do Castelo, Portugal.
Semi-submersible floating wind turbines off the coast of Viana do Castelo, Portugal. Photography: Hugo Amaral / Sopa Images / Rex / Shutterstock

America’s First Floating Wind Farm may end up in Maine, where the University of Maine, RWE Renewables and the Mitsubishi subsidiary Diamond Offshore Wind are developing a small demonstration project that would generate 12MW of power.

He has faced enormous opposition from lobster fishermen who say the turbines interfere with their business. They reached a compromise in July: This pilot project will go ahead but the state legislature approved a ban on new industrial wind projects in state waters until March 2031.

Fishermen have also sounded the alarm about the California projects. “Too many questions remain unanswered regarding potential impacts on marine life,” said Mike Conroy, executive director of the Federation of Pacific Coast Fishermen’s Associations in a May month. statement on floating wind plans in the state.

Walt Musial, NREL’s offshore wind research leader, said that even a large-scale deployment of offshore wind power along the east or west coast would occupy only a small part of the ocean and the turbines would be carefully located. But he highlighted the continuous need for good communication “to ensure optimal coexistence and help the fishing community to adapt and continue to access the space inside the turbines to fish.”

California government plans to offer commercial leases for Morro Bay and Humboldt Bay next year. Stern is hopeful that floating offshore wind will create thousands of well-paying clean energy jobs in the state, as well as accelerating the decommissioning of natural gas plants, reducing pollution in communities that disproportionately bear the burden of environmental impacts.

“There are many challenges in getting floating wind turbines to work in American waters,” said Po Wen Cheng, “but there is no question about the potential.”


www.theguardian.com

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