The first U.S. offshore wind farm is expected to go online by the end of 2016, ushering in what could be a new era of renewable energy in the United States.
This is welcome news in a nation where land-based wind power has exploded over the past two decades, installing nearly 50,000 wind turbines that provide clean energy across the continent. Can the same spirit of innovation that made U.S. land-based wind power a world leader be applied to offshore power?
We’d like to think so, but, admittedly, there is a long way to go. The new Block Island Wind Farm is barely a blip on the nation’s energy map — powering just 17,000 households in a nation of 325 million people.
Completed in August at a cost of $290 million, the Block Island Wind Farm consists of five turbines towering over the waters of the Atlantic Coast south of Rhode Island. It might not sound like much in an age where thousands of offshore wind turbines pump carbon-free electricity to Germany, the U.K. and other European nations.
But it’s difficult to exaggerate the importance of the U.S. finally dipping its toes in the water, so to speak, of offshore wind. An abundance of caution on American shores had thwarted every previous offshore wind project. Now that offshore wind technology is mature thanks to a couple decades of European development, the U.S. is poised to reap the benefits of potentially cheaper offshore wind power.
This helps explain why several states along the Eastern Seaboard are embracing offshore wind power:
- The governor of Massachusetts approved a program in August allowing up to 1,600 megawatts of offshore wind projects in the next decade.
- New York approved a plan in August that says renewable power sources (wind, solar, etc.) must account for half of the state’s energy output in 2030. In September, the state released a blueprint for an offshore wind master plan to be completed in 2017.
- At the University of Maine, researchers are working with federal grants from the Department of Energy to develop prototypes of floating wind-farm platforms that can overcome many of the challenges associated with fixed offshore wind turbines. A French defense firm that’s moving into the renewables sector also has joined the project.
Projects on the drawing boards could add nearly 5 gigawatts of offshore wind power in the United States — a mere fraction of the estimated 4,200 gigawatts of energy that could be generated in the domestic waters of the United States.
Any offshore wind projects will have to overcome substantial regulatory and financial hurdles before any electricity starts streaming back to the mainland. But it’s worth the effort.
Why offshore wind is crucial to the U.S. energy equation
Offshore wind technology is more expensive to install and maintain than its land-based counterparts. But ocean breezes are stronger and more consistent than the wind passing over land, which creates the potential for much more efficient wind-energy operations installed offshore.
In effect we can conceivably pull more power from fewer turbines if offshore wind technology matures. Installing and maintaining these towers will require substantial expertise, which could produce a lot of steady jobs for coastal communities.
Meanwhile, the U.S. fracking boom that has done so much for the nature’s energy posture — lowering gas and oil costs and reducing the dominance of OPEC — remains politically controversial. If the public tide were to turn against fracking, we could see renewed pressure to tap green-energy sources like offshore wind.
Embracing the power of our oceans
At PMI, we’re strong believers in the potential of marine energy technologies because we’ve been providing rugged cable accessories to offshore industries for decades. To be viable, offshore wind farms must be able to cope with ever-present threats to subsea power cables that transmit electricity back to the mainland. Our cable terminations, cable protection and splices are built to withstand the worst our oceans can deal out, so naturally we’re embracing the potential of offshore wind.
The oceans alone won’t fix all of America’s energy problems, of course. But they should be part of the solution.
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Whether marine energy project planners deploy wind, wave or tidal devices, they cannot afford to overlook the basics: transmitting power back to the mainland via electrical cables.
There’s an abundant body of knowledge on transmitting electrical power via underwater cables because power companies have been doing it decades. Indeed, Europe’s mature offshore wind industry has amassed considerable working knowledge on the most common challenges of subsea electrical cables.
Here’s a concise overview of them:
Installation and Positioning
Power cables for marine energy projects most likely will be installed with cable-laying machines that bury them at a specific depth below the sea floor. This is mature technology; the main challenges are straightforward: working around the weather and hiring a ship to lay the cables.
The greater challenges come from determining exactly where the cables will go. A host of position-related questions crop up:
- Are any other cables or utility pipelines already installed nearby?
- What’s the regulatory status of the installation site — is it a protected ecosystem?
- What’s the seabed terrain like?
- How stormy is the local weather?
- How far apart should cables be placed?
- How much shipping, fishing and other commercial activities happen nearby?
An in-depth review by the U.S. Department of the Interior’s Bureau of Safety and Environmental Enforcement noted that there so many variables with cable installation that project specifics will have to be decided on a case-by-case basis.
Protection
Cables must be built to withstand the rigors of the subsea environment. Furthermore, any cable accessories that connect various cable parts have to be extremely rugged and seaworthy, providing reliable cable protection, terminations and splicing. Project planners need to invest time in researching accessories that strengthen and protect cables, making them less vulnerable to corrosion, currents and other subsea threats.
Mooring
Depending on the location, some cables require mooring lines to hold them in place. These lines may require anchors embedded in the sea floor. Once the cables are moored, the lines may attract aquatic species that start building artificial reefs; this may trigger environmental questions.
Maintenance and Repair
The ocean environment does not cooperate with the need to maintain and repair subsea cables. Ship anchors and fishing nets may snag your power lines, and inconvenient storms can keep repair crews away for weeks or months. Even in the best weather, it can be extremely difficult to identify precisely where a cable is damaged.
Fortunately, technology is getting much better at predicting when parts will fail so replacements can be installed on schedule rather than in a chaotic emergency-repair scenario.
Monitoring
A power grid buried beneath the sea floor requires constant surveillance — the environment creates so many challenges and risks that it’s extremely difficult to anticipate all the ways things can go wrong. Advances in monitoring technology will help narrow down the source of a problem when it crops up, but it’s still a matter of fixing things buried under seawater. That’s always a challenge.
Addressing the complexities of subsea cable grids
All these points illustrate the need for a well-planned, well-executed marine energy project that anticipates the many challenges that crop up when devices and equipment get placed in a saltwater environment.
At PMI, we pay a lot of attention to making sure splices, terminations, cable protection and other accessories do not become weak links in a subsea power grid. With all the risks in the subsea environment, investing in the best cable accessories can mean one less worry for marine energy project planners.
Related articles:
- Subsea Cable Trade Group Widens Focus to All of Europe
- Offshore Wind Farms Still Learning How to Handle Cables
- What kind of ocean equipment will be needed for subsea power grids?
Are floating platforms the future of marine renewable energy?
It’s hard to tell just yet. Floating platforms have been bulwarks of the oil and gas industries for decades. If we can use a floating platform to drill from the ocean surface down through kilometers of bedrock, how hard could it be to mount a wind turbine or other marine energy converter on a floating platform and transmit electricity back to the mainland on cables?
The engineers tackling this question have a lot to think about. Most of their debates will shape up along the pros and cons of floating platforms for marine renewable energy. Here’s a quick look at them:
Advantages of Floating Platforms
Invisible to landlubbers. Folks on land don’t have to look at floating platforms, which can be deployed beyond the horizon and protect precious ocean views. This makes offshore wind more politically palatable.
Simplified, flexible deployment. A floating wind turbine platform can be towed out to sea fully constructed. This could potentially be much simpler and less costly than the specialized ships required to deploy embedded wind farms. Note, however, that a special port facility would still be required for the construction phase, so it’s unclear how much savings this produces in the short run.
Greater water depths. Fixed offshore renewable energy projects work best in shallow water — typically less than 200 feet (61 meters). Floating platforms, by contrast, can be deployed in waters up to a half-mile deep (800 meters) or even more.
Stronger, more reliable winds. Near shore, moving air becomes much more turbulent and dispersed. A few miles out to sea, the winds are more powerful and reliable, generating much more potential electricity. At the same time, manufacturers are building ever larger wind turbines to catch more air — so it only makes sense that these be used on floating platforms.
Turbines can be swapped out. If a fixed wind turbine goes bad and has to be replaced, it’s an incredibly complex project. Floating platforms, by contrast, can be quickly and easily towed into place or removed.
Easier inspections and maintenance. This is most true with wave- and tidal-power systems that are deployed underwater. Fixed systems are much harder to inspect and repair than floating systems.
Disadvantages of Floating Platforms
Cost comparisons. Fixed offshore wind technology gets more mature every year, lowering total costs with each new innovation. As long as these costs keep falling, floating platforms will face daunting challenges in attracting investors.
Unsettled engineering. A few floating-platform systems are in the water, but not enough to provide a clear picture of the optimum platform. A standard platform that can be manufactured at scale will be required to produce the economies that make offshore platforms viable.
Environmental questions. Floating platforms require anchors on the seabed and connecting cables or chains that can disrupt offshore ecosystems. Though most biomes can adapt to the temporary construction disruption, there’s always the potential of creating artificial reefs that invite invasive species. The effects on migratory animals like whales and birds also are unknown.
Cable complexities. Extra-heavy-duty cables are required to fix floating platforms in place and endure the ravages of waves and saltwater. Suppliers in this space will need extensive experience in both deep-sea mooring lines and electricity transmission cables.
Don’t Discount the Potential of Floating Platforms
At PMI, we’re excited about the idea of adapting our decades of deep-sea cable experience to the needs of the marine renewables sector. It might not be happening as soon as we would prefer, but as long as nations around the globe establish benchmarks for tapping into the potential of renewable power, they’re going to keep looking to their shorelines — and beyond.
Related articles:
· Market Opportunities for Offshore Wind: What Does the Future Hold?
· Challenges in the Installation and Repair of Offshore Wind Turbines
· Subsea Cable Trade Group Widens Focus to All of Europe
Offshore wind technology gets better every year with more innovative turbine and blade designs. But no matter how well they design a wind turbine, engineers perpetually confront the unique difficulties of exporting electricity back to shore.
Subsea power cables are built with the demands of open ocean in mind. Multiple layers of alloy and fiber strengthen and protect the power-conducting cables inside. In the open ocean, far from ship anchors and fishing nets, deep-sea communication cables can last for decades without a fault.
Power cables installed near dry land have it much tougher because they are so much closer to the ocean surface, where turbulent weather and heavy machinery can cause havoc. Indeed, an article at RenewableEnergyFocus.com estimated that export cable damage surged by 500 percent in the past 12 months.
Survivability is the central concern of cable manufacturing because oceans bring peril with every wave. Typhoons, fishing trawlers, corrosion — it’s always something. Here’s a quick look at the key challenges with power cables that export electricity from offshore wind farms:
Finding the Damage
Occasionally, a ship anchor will snag a cable and snap it in two. This is bad news because it shuts off a revenue source for the offshore wind operator, but it could be much worse.
A pure break location is somewhat easy to track down because engineers can measure the resistance in a length of power cable and calculate with a fair degree of precision where the electricity cuts off. Then it’s a matter of sending a ship to the estimated location of the break, pulling up the broken cables and using splicing gear to reconnect them.
The much more daunting challenge happens when a cable starts developing significant losses in transmission — often because the cable was damaged and exposed to the corrosion of seawater. This kind of damage is less likely to leave telltale hints about its location, which can bog down the pace of attempted repairs.
Reducing Downtime
Windfarm designers have figured out how to build towers and turbines that can withstand gale-force winds and furious storms. Unfortunately, the worst weather may damage even the most well-built cables, which requires ships to locate the problem and try to fix it.
Repair crews cannot do their jobs in storms that toss their giant vessels around like corks. So they have to wait for the weather to calm down. It might take days; it might take months.
It’s not unheard of for a ship to be at sea for three months in pursuit of a single repair if severe storms continually blow it off course. There are only so many ships available, and they can fix only so many damaged cables.
Making Repairs
Once a repair ship locates a cable problem, it has to pluck the cable from the ocean floor and pull it up to the surface. If all goes well, this process won’t damage the cable even more.
After the damaged area of cable arrives at the surface, the next step is to recondition the broken areas, rejoin any damaged conductors, then seal the assembly with heavy-duty splicing equipment. The techniques for repairing and rejoining subsea power cables are well understood. But repairs are still hostage to the first two problems: finding the cable fault and waiting out the weather.
This is Why Subsea Cable Accessories Must be the Best of the Best
All these challenges give offshore wind operators plenty to worry about. The accessories that attach and connect their power cables should not be another source of anxiety.
At PMI, we aim to provide the most durable, practical subsea power cable accessories on the market. We’re big believers in the promise of offshore wind and other marine renewable power sources, but we’re also realistic about the depth of the challenges facing the industry.
It may turn out that difficult cable repair jobs are the price we have to pay for offshore renewables. If so, we’ll do our part to make sure those fixes stay fixed.
Related articles:
- Damage to Subsea Cables a Huge Risk to Offshore Wind Farms
- Challenges in the Installation and Repair of Offshore Wind Turbines
- Offshore Wind Farms Still Learning How to Handle Cables
- Vision for Offshore Wind Energy Market
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Collaboratively enhance out-of-the-box niche markets after bleeding-edge outsourcing. Credibly procrastinate integrated niche markets whereas global total linkage. Intrinsicly repurpose B2B paradigms vis-a-vis extensible solutions. Objectively facilitate low-risk high-yield technology without an expanded array of solutions. Quickly unleash real-time value vis-a-vis cross functional ROI.
Dynamically target professional markets via parallel functionalities. Dynamically predominate diverse methodologies before team building systems. Efficiently redefine enterprise-wide meta-services via frictionless ideas. Compellingly build maintainable collaboration and idea-sharing whereas 2.0 action items. Seamlessly network extensive experiences for resource-leveling imperatives.
Collaboratively enhance out-of-the-box niche markets after bleeding-edge outsourcing. Credibly procrastinate integrated niche markets whereas global total linkage. Intrinsicly repurpose B2B paradigms vis-a-vis extensible solutions. Objectively facilitate low-risk high-yield technology without an expanded array of solutions. Quickly unleash real-time value vis-a-vis cross functional ROI.
Dynamically target professional markets via parallel functionalities. Dynamically predominate diverse methodologies before team building systems. Efficiently redefine enterprise-wide meta-services via frictionless ideas. Compellingly build maintainable collaboration and idea-sharing whereas 2.0 action items. Seamlessly network extensive experiences for resource-leveling imperatives.
Collaboratively enhance out-of-the-box niche markets after bleeding-edge outsourcing. Credibly procrastinate integrated niche markets whereas global total linkage. Intrinsicly repurpose B2B paradigms vis-a-vis extensible solutions. Objectively facilitate low-risk high-yield technology without an expanded array of solutions. Quickly unleash real-time value vis-a-vis cross functional ROI.
Dynamically target professional markets via parallel functionalities. Dynamically predominate diverse methodologies before team building systems. Efficiently redefine enterprise-wide meta-services via frictionless ideas. Compellingly build maintainable collaboration and idea-sharing whereas 2.0 action items. Seamlessly network extensive experiences for resource-leveling imperatives.
Gravity from the sun and moon tugs at the surface of our oceans, creating tides that move massive quantities of water across broad expanses of shoreline twice a day. All that moving water produces kinetic energy we can convert into electrical power.
Though all of the earth’s continents have shorelines and tides, we haven’t done much with all that energy. To date, tidal energy technology generally takes two forms:
- Tidal current converters. These devices are typically underwater turbines that look much like a wind turbine and capture energy from water moving past the blades.
- Coastal barrages. A barrage is a kind of dam across the opening of an estuary. It works much like a hydroelectric plant, except that it uses turbines to capture energy from rising tidewater rather than river water.
Current technologies offer only a glimpse at tidal energy’s potential. To get the whole picture, we need to weigh the pros and cons of tidal energy.
Here’s a quick summary: (more…)
Generating electricity from waves or tides requires placing large mechanical devices in the middle of complex, fragile ecosystems. How will life respond to these intrusions?
Because we’re so early in the evolution of marine energy, environmental concerns post a host of serious questions, such as:
What have we learned from the development of artificial reefs?
Fixed structures in the ocean naturally invite the arrival of reef species, creating artificial reefs. If the introduction of reef species boosts the biodiversity of a marine energy project area, the development could be a net benefit.
However, if reef species include predators that wipe out local species that have no natural defenses, then the effect could be negative. Early projects will have to be studied intensely to see how this works out.
How will migratory species respond?
A large network of marine energy devices could force migrating mammals, fish and birds to change their travel paths. Even subtle changes can throw off reproductive rhythms that evolved over millions of years. If these changes make it harder for migrating species to reproduce, or weaken them so they are more vulnerable to predators, the cost could be substantial.
Will wave-energy devices change the dynamics of shallow shorefront ecosystems?
Dozens or hundreds of marine-energy devices in a well-defined region can affect the velocity of waves striking the shore. Small changes in the depths of tidal pools or the thickness of sand layers could influence species’ ability to feed and reproduce. How will we determine an acceptable level of risk or damage in these scenarios?
Can wave energy devices pollute local waters?
Marine energy devices require lubricants that could potentially leak and cause pollution. Furthermore, the substantial corrosive nature of seawater will wear these machines down quickly, expanding the risk of pollution. Granted, most devices would not carry enough lubricants to create a substantial oil spill. But persistent small leaks spreading over months and years could still have a profound impact.
Can devices survive exposure to pollutants?
The concerns over potential pollution by marine energy devices shouldn’t obscure the possibility that offshore sites might already be polluted with chemicals that could damage these devices. Even undisturbed sites pose a challenge: Could large chemical or oil spills disable devices installed in them?
What happens to fisheries?
The livelihoods of people in the fishing industry depend on healthy ecosystems that support fisheries. Any project will have to weigh the economic, social and environmental impact on coastal industries like seafood.
How will environmental regulations affect marine energy projects?
Regulators and rule compliance will be a fact of life for the marine energy sector. Developers will need to court the regulators to figure out exactly what it takes to stay compliant. Regulators may also conduct impact assessments that discover rare endangered species, which could grind everything to a halt.
Finding the right ways to draw energy from our precious oceans
The rise of marine energy is a natural progression for PMI, which has been providing rugged, durable cable accessories to the energy-exploration industry for decades.
Though we are enthused about the possibilities of marine energy, we respect the need to tap this energy source without damaging delicate marine ecosystems. Sure, that adds extra layers of time, expense and complexity. But it’ll be worth it to keep our oceans as healthy as possible.
