With more than 95,000 miles of shoreline, the United States looks like an ideal candidate for offshore wind energy development. But it’s not that simple.

A substantial portion of U.S. shoreline tracks the Southern Atlantic states and the Gulf of Mexico, where the winds are either too weak most of the year or potentially catastrophic during hurricane season. The Pacific Coast has steady, powerful winds, but the continental shelf drops off sharply near the shore, requiring floating wind-power platforms that cost much more than fixed-position wind farms.

The economics of offshore wind present a second order of complexity. Offshore wind developers have to weigh factors including:

• Costs of competing energy sources like coal and natural gas
• Population density of the area using the power
• Availability of subsidies and renewable energy credits
• Expense of designing, manufacturing, and deploying wind farms

An intriguing study from the Berkeley Lab’s Electricity Markets & Policy Group developed a series of models to compare the economic value of offshore energy projects along the Eastern Seaboard of the United States from 2007 to 2016:

“The market value of offshore wind between 2007-2016 varies significantly by project location and is highest for sites off of New York, Connecticut, Rhode Island, and Massachusetts,” the study found.

States with most promising developments

In a May 2018 article, POWER magazine listed the most promising states for offshore wind. That roundup included:

• Massachusetts. With the doomed Cape Wind project finally out of the picture, the prospects for other offshore power projects are improving. The state government has passed legislation targeting 1,600 MW of offshore wind power by June 30, 2027. The law requires a buffer of 10 miles between offshore wind farms and inhabited areas to avoid angering the public, which prizes its coastal views. Three companies are bidding for projects off Martha’s Vineyard.
• Maryland. Two companies have been awarded renewable energy credits to develop wind farms of 120 MW and 248 MW. The credits are worth $3.6 billion over two decades. Developers are required to create nearly 5,000 jobs and invest in a steel fabrication plant and port upgrades. The project will involve 77 turbines from 12 to 21 miles offshore.
• New York. Gov. Andrew Cuomo would like to see 2,400 MW of offshore wind power developed in the next two decades. He wants to start with 800 MW in 2018-19.
• New Jersey. The state’s Offshore Wind Economic Development Act, passed in 2010, sets a goal of 3,500 MW of new power generation by 2030. The state’s Board of Public Utilities plans to solicit 1,100 MW of new projects, which would be the nation’s largest so far.

States and projects further down the coastline in Georgia and the Carolinas appear much less likely to bear fruit, the POWER magazine article explained.

Pacific Ocean possibilities

The Pacific Coast and the Hawaiian Islands each present intriguing opportunities because their terrain limitations require innovations in floating offshore platforms. Unlike Europe’s North Sea and the Eastern Seaboard of the United States, the shoreline of the Pacific plunges to depths that are impractical for the development of standard offshore wind turbines mounted on the seafloor.

In May 2018, the U.S. Navy complicated matters even further, stating that vast swaths of California coastline — including all of Southern California — should be off-limits to wind farms because the Navy needs that space for national defense purposes, the Los Angeles Times reported. The Navy cannot decide where wind farms will be deployed, but it has considerable influence.

Perhaps the best news for the Pacific comes from the coast of Scotland, where the first floating platform offshore wind farm is up and running. That wind farm is proving to be remarkably energy efficient, using up to 65% of its capacity factor, which is far better than land-based gas and coal power, according to Greentech Media. Capacity factor estimates a powerplant’s output as a percentage of its theoretical full energy output.

With the cost of developing offshore wind farms falling rapidly and floating platforms showing promise, power from the Pacific might be closer to reality than many observers suspect.

Great Lakes

A wind farm project in the works near our home base in Cleveland will test the viability of the Great Lakes, which have ample wind, high population densities, and relatively shallow water.

The Icebreaker project plans to deploy six turbines in Lake Erie about 8-10 miles northwest of Cleveland. Supporters hope this pilot project becomes a catalyst for further development throughout the Great Lakes.

Offshore wind is coming to U.S. shores

Many coastal states have ambitious renewable-energy goals that will require the development offshore wind because there’s only so much they can do with solar, land-based wind, and biofuels. Fortunately, they can benefit from decades of European experience in offshore wind combined with steep declines in development costs.

U.S. wind projects also raise the prospect of bringing good-paying jobs and economic development to communities that need a boost after declines in their manufacturing base.

As a manufacturer of premium cable accessories for offshore wind and other marine-energy projects, PMI is doing its part to support the industry and help reduce our reliance on fossil fuels. We believe the United States is ready for offshore wind, and judging from the volume of new projects in the pipeline, we’re not alone in that assessment.

Related articles:

America’s First Offshore Wind Farm Is Finally Ready for Prime Time

Why the U.S. Should Embrace Offshore Wind

How Ice Could Impact Subsea Cables and the Great Lakes’ Offshore Wind Success

The Cable Challenges of Saltwater vs. Freshwater for Offshore Wind Projects

The challenges of developing practical, economical offshore wind power are pushing engineers and entrepreneurs to new heights — and depths — of ingenuity.

We’ve talked about the pitfalls and potential of offshore wind and other marine renewables for years in our Ocean Engineering Blog. We’ve noted that it’ll never be easy to build technologies that must be submerged in corrosive, turbulent subsea environments. And marine-renewables will remain a tough sell as long as oil prices stay low.

But these challenges haven’t stifled innovation in the ocean-renewables sector, especially offshore wind. Here’s a look at some of the encouraging news we’re seeing:

Autonomous underwater and remote-operated vehicles (AUVs, ROVs)

The cost of deploying ships and divers to inspect, maintain, and repair cables and other subsea components has been a costly drag on offshore wind farms for decades. Widespread adoption of versatile, low-operating-cost AUVs and ROVs can reduce those costs substantially.

As we learned at Subsea Expo 2018 in Aberdeen, Scotland, companies developing advanced AUVs and ROVs are adding new capabilities that, for instance, add a cutting tool to an inspection AUV. Another promising development is underwater charging stations that allow subsea vehicles to roam free without cables. Instead, the stations themselves have cable connections to power sources.

Larger, more powerful turbines

GE Renewable Energy’s forthcoming Haliade-X 12-mw turbine underscores the drive to build ever-larger devices that produce more energy in a single tower. Billed as the most powerful turbine on the planet, the Haliade-X will be able to power 16,000 European households with a single turbine. That means a single wind farm of 50 towers could serve 800,000 households — potentially a city of more than 2 million people.

Standing 260 meters high with a 220-meter rotor, the Haliade-X will produce 45% more energy than any other turbine on the market, GE says. It’s expected to start showing up in wind farms in 2021. For more on the size challenges in offshore wind, see this profile of former Siemens CTO Henrik Stiesdal in Wind Power Monthly.

Floating platforms

The prospects for offshore wind farms on floating platforms got a boost in March 2018 when Statoil announced its new floating platform off the coast of Scotland reached a 65% capacity factor for November 2017 through January 2018 — besting a host of competing power sources. That news supports the principal rationale for floating platforms: deploying them farther from shore, where the winds are stronger and more consistent.

Capacity factor estimates a powerplant’s output as a percentage of its theoretical energy capacity. Greentech Media noted that U.S. onshore wind farms have a capacity factor of 37%, while coal- and gas-fired power plants have capacity factors of 54-55%.

Suction-bucket foundations

Floating platforms could be the future of offshore wind, but most projects in the next few years will keep using towers anchored to the seabed. Current anchoring methods create an abundance of noise, disturbing sea life and generating concerns about the environmental impact of offshore installations.

A new alternative is the suction-bucket foundation, which uses a base shaped like an inverted bucket. It works like this: After the bucket settles on the seafloor, operators pump out all the water inside it, creating a pressure differential that helps fix the bucket in place. When it’s time to decommission the bucket, water can be poured back into it. The first commercial-scale suction-bucket foundation in a wind farm was installed earlier this year off the coast of Scotland, Powermag.com reported.

Research updates

Here’s a look at recent research in the offshore-wind sector:

• Seabird avoidance. Seabirds have little trouble avoiding the spinning blades of offshore-wind turbines, a new study finds. Windpower Engineering & Development summarized results of the Bird Collision Avoidance Study, which used video cameras and high-tech sensors to track bird movements around a working wind farm in the English Channel. The study analyzed more than 600,000 videos monitoring activity at the wind farm. Of those, about 12,000 showed bird activity. Notably, the videos captured a scant six collisions over the course of the study.
• Anti-corrosion studies. Offshore Wind Journal reviews reports pointing to potential solutions to the nagging problem of corrosion in subsea environments. The reports estimated that reducing corrosion could generate savings in the tens of billions of dollars throughout the ocean-renewables sector over the next three decades.

Offshore wind keeps showing more promise

These updates offer just a glimpse of the encouraging developments in the offshore-wind sector. As turbines grow more powerful and engineers figure out new ways to reduce costs and protect subsea ecosystems, it will become ever more realistic to depict offshore wind as an experimental power source with mainstream potential.

Related articles:

Innovations Shrink Offshore Wind Timelines

Artificial Island Sparks Innovation In Wind Energy

Pros and Cons of Floating Platforms in Marine Renewable Energy

Ice hasn’t necessarily put a chill on the development of offshore wind in the Great Lakes of North America, but it does pose a significant challenge — both in the design of offshore wind turbines and the maintenance of subsea power transmission cables.

Winter is a wildcard for the Great Lakes because the offshore wind industry has traditionally avoided ice-prone regions. Most new oceanic wind farms can tap decades of knowledge gleaned from the maturation of Northern Europe’s offshore wind industry.

That’s not exactly the case for projects in water that freezes every year. The first wind farm designed specifically to cope with ice opened off the west coast of Finland in the autumn of 2017. The 42-megawatt Tahkoluoto wind farm relies on gravity-based foundations that are tapered at water level to resist friction with ice.

Ice and subsea cables

Reports on the Finnish wind farm have mentioned the tower base design but haven’t delved into the implications for subsea cables. We’re not privy to the technical specifications of the project’s subsea cables, but we can offer a few insights based on our decades of experience with subsea cables in harsh environments:

• The extreme weight and mass of ice place relentless pressure on anything in its way. Wind farms on the Great Lakes have to be designed with these risks in mind, laying cables strategically to keep them away from ice flows and buildups. The inherently unpredictable nature of weather and the motion of ice could conceivably surprise wind farm developers.
• Winter repairs will be extremely complicated. It’s difficult enough to send a ship to the site of a cable break in the open sea — it can take weeks or months to get a crew to the site, fetch the cable, repair it, and return it to the seabed. Imagine attempting repairs in the winter in the Great Lakes where variable weather changes the ice thickness constantly.

Engineers can design for the most likely scenarios for subsea cables, but there’s nothing like real life to teach us lessons we couldn’t foresee with ice and wind farms.

The value of wind farms in icy locales

The abundance of strong winds across the Great Lakes creates opportunities to develop new technologies and engineer novel solutions to icy problems. As ice resides along Arctic coastlines, wind farm developments could bring clean power to remote communities that otherwise depend on fossil fuels for heating and light.

However, we can only figure out so much of what is on the drawing board. To understand the depth of the challenges of ice in offshore wind, people need to build wind farms and learn the lessons nature inevitably provides.

At PMI, we look forward to engineering rugged, high-performance subsea cable accessories that will be critical to the success of wind power in the Great Lakes and beyond.

Related articles:

• Market Opportunities for Offshore Wind: What Does the Future Hold?
• Vision for Offshore Wind Energy Market
• Damage to Subsea Cables a Huge Risk to Offshore Wind Farms

The corrosive effects of saltwater on subsea cables and accessories are well known.

Freshwater doesn’t have quite the same impact, but it still raises a range of issues for offshore wind developers. The saltwater vs. freshwater comparisons are becoming more relevant as offshore windfarm projects along the Great Lakes of North America — the largest expanse of freshwater on Earth — inch closer to reality.

Why the Great Lakes? Anybody who ever felt a summer gust from Lake Michigan in Chicago’s Loop or an icy blast from Lake Erie in downtown Cleveland understands. The vast open spaces of the Great Lakes allow strong Midwest winds to blow unimpeded.

Is it only a matter of time until the windfarms dotting the plains of North America extend to the Great Lakes? Perhaps, provided developers can apply the lessons of saltwater windfarms to the distinct needs of freshwater environments.

Saltwater challenges for subsea cables and accessories

Saltwater environments have specific impacts on subsea cables and accessories:

• Oxidation: Saltwater can corrode the surface of any metal. Carbon steel, for instance, is strong and cost-effective, but requires treatment to resist oxidation.
• Anodic corrosion: Because saltwater is an electrolyte, it triggers an electrochemical process at the contact points of dissimilar metals, such as cooper, magnesium, and carbon steel, that leads to corrosion.
• Live current: Subsea cables carrying current can generate electromagnetic fields of varying magnitudes. When the flow of water is perpendicular to the axis of the cable, the magnetic field begins interacting with seawater, or a charged object. There are variables which impact the intensity of the field which in turn impacts the amount of damage that can occur. Depending on the speed of saltwater passing over the cable, the diameter of the cable, and the amount of current, some high-velocity tidal areas can cause corrosion.
• Aquatic species: Barnacles, in particular, attach themselves to everything that goes in seawater. Once they attach themselves, they are extremely difficult to remove.

Freshwater challenges for subsea cables and offshore wind projects

Though freshwater is not nearly as corrosive as saltwater, it can be problematic in three ways:

• Ice: Each year, a significant portion of the Great Lakes is covered with ice, which complicates the construction offshore wind projects. During the winter of 2013-2014, 92% of the Great Lakes were frozen over. Companies in Scandinavia have figured out how to build towers in lakes that freeze, so ice need not be a deal-breaker in the Great Lakes.
• Pollution or foreign substances: Pollutants are wildcards in the construction of windfarms because it’s difficult to predict future pollution levels. Thus, engineering subsea cables and accessories to resist the impact of pollutants is imperfect at best.
• Human uses: The Great Lakes are busy shipping routes and recreational areas, and any offshore wind farm project would have to keep those factors in mind. Ships hauling goods and raw materials could potentially damage or threaten the electrical cables from freshwater windfarms. Boundaries would also have to be set up to prevent contact with boats and the people in them.

The power is there — the question is how we use it

The winds over the Great Lakes average 16 mph, according to the Natural Resources Defense Council. And governing bodies along the U.S. side of the Great Lakes are looking toward a future that includes windfarms, the Sierra Club notes on its website.

We mention these advocacy groups because they cautiously support windfarm development in the Great Lakes. Offshore windfarms attract well-deserved environmental scrutiny, but they still represent sources of clean, renewable energy sources for densely populated areas. The continued support of environmental groups will be key to the rise of offshore wind in the Great Lakes.

Power draw makes a case too. Summer months require more energy for climate control which can cause major outages when the grid is not prepared. Having an additional energy supplement will help prevent outages and make grids more reliable.

As we’ve noted many times in our blog, PMI is committed to supplying the rugged, long-lasting subsea cable accessories that windfarms need to defend their power lines against the subsea dangers.

Related articles:

• Market Opportunities for Offshore Wind: What Does the Future Hold?
• Vision for Offshore Wind Energy Market
• Damage to Subsea Cables a Huge Risk to Offshore Wind Farms