Wave power looks like a no-brainer at first glance. After all, oceans cover more than 70 percent of our planet’s surface, and waves lap up on the shores of all seven continents.
Just build machines to convert those waves into electricity and we’re all set, right?
Alas, wave energy challenges can be as deep as the ocean itself.
The future of the offshore wind market depends on where you’re standing.
- In Europe, the offshore wind market is so well established that new generations of equipment are replacing obsolete machinery.
- In North America, the industry is so new that it exists largely on the drawing boards of offshore-wind developers.
- In Asia, it’s somewhere in the middle as China ramps up its offshore wind capacity.
Installing and maintaining offshore wind turbines is an incredibly complex undertaking full of daunting logistical challenges.
For starters, ships built to install turbines can cost $100 million or more. Stormy weather can delay installations and thwart repairs. Weather and erosion exact a long-term cost on turbine blades, and turbine engines must be painstakingly designed for always on-operation for decades.
Here’s a quick look at some of the difficulties in installation and repairs in offshore wind installations:
Placing a foundation on the sea floor is a sophisticated, highly complex job. A gravity-base foundation uses a large volume of reinforced concrete and must be moved to a carefully prepared spot on the seafloor. All this requires specialized ocean vessels and specific expertise.
Sea floors vary widely around the world. For instance, the sea bed off the coast of China is a lot different than the sea bed of European waters, so foundation expertise gained in Europe might not apply in China — adding to the complexity (and expense) of China’s ambitious offshore-wind agenda.
Once the foundation is installed, it becomes vulnerable to saltwater corrosion and underwater species that attach themselves and may have to be eventually removed at considerable cost.
Longer turbine blades produce much more energy than shorter ones, so the blades keep getting longer and longer as the offshore-wind industry evolves. Obviously, longer blades will create extra complications in transport and installation.
But the bigger challenge is in maintenance. Blades suffer substantial erosion from constant exposure to the wind that decreases their efficiency. They often also suffer lightning strikes that cause considerable damage below the wind-facing surface.
And the manufacturing processes of turbine blades are not completely standardized, so maintenance processes for one kind of blade can be substantially different than those on another variety. This adds to the difficulty of finding and training people to perform maintenance on turbine blades
Turbine engines are large mechanical devices suspended high in the air. Installation is fairly straightforward because the offshore wind industry is so mature in European waters. But it’s still a non-trivial job to install a wind turbine engine in the open ocean because of the usual weather pressures.
Because they run 24 hours a day for years on end, turbine engines must be carefully designed and manufactured to close tolerances to minimize breakdowns. An article in Forbes magazine likened running a wind turbine for 20 years to getting 3 million miles from a car engine.
Turbine engines have lots of moving parts including bearings and gears that eventually wear out. This cannot be entirely avoided, but it can be monitored with increasingly sophisticated computer software that can predict when critical parts will fail, and allow them to be removed before they give out and cause serious damage to the machinery.
The technology for laying transmission cables is mature and the techniques are well understood. At PMI, we’ve been building premium, high-performance subsea cable accessories for decades, so we’ve seen these developments up-close.
The biggest maintenance challenges for transmission cables happen if they get snagged by ship anchors or fishing-trawler equipment, or if they’re damaged in subsea landslides. These mishaps require sending highly trained crews to the site of the break and fashioning a repair at sea. That will always be expensive and time-consuming.
Costs cannot be ignored
Offshore wind remains very expensive to install, maintain and operate. WindEurope (formerly EWEA) reports that offshore wind LCoE must be reduced in order for it to “remain a viable option in the long-term.”
This places a lot of pressure on offshore-wind operators to find ways to reduce these kinds of costs. Using cheaper materials may be attractive in the short run, but if it adds to long-run maintenance costs, it’ll be a bad bargain because fixing things at sea is so much more complex.
In theory, thousands of miles of shoreline should make the United States an ideal locale for developing marine renewable energy.
But tapping the energy from all the waves pounding the shores of the Atlantic, Pacific and Gulf coasts of the U.S., is an incredibly complex prospect. A wide range of obstacles must be overcome.
The wide variety of sea depths in the offshore waters of the U.S. create a whole host of difficulties.
Tidal energy, for instance, needs tides to rise and fall at least 16 feet or more to be a practical energy source. Only a few places in the U.S., in Maine and Alaska, have tides that large.
Wave energy has great potential in some areas like California and the Pacific Northwest, which get a substantial volume of large waves (just ask the surfers), but it’s less attractive in areas where the waves are smaller like the Gulf of Mexico and much of the Atlantic Coast.
We can’t discuss marine energy without at least mentioning offshore wind. It’s not considered a marine-energy technology but it does go in the ocean, so it’s part of the ocean-renewable energy picture. The Atlantic and Pacific oceans are very different; what works in the Atlantic won’t work the same way in the Pacific.
Only a few ocean-energy devices are being tested in North America and we still do not have a clear picture of which technologies do the most good for the most people at the best cost.
Another challenge noted recently by The Energy Times magazine is that we need a lot more grid-connected test systems in place to see how these projects work when actually delivering power to the electricity grid. The U.S. Navy has one such grid set up for a wave-energy project in Hawaii, Energy Times notes, but projects in the works in Oregon are still not connected to the grid.
The United States has a robust environmental regime. Any marine renewable energy project in U.S. shores will face considerable regulatory scrutiny.
Devices will have to be anchored without causing substantial disruption to local underwater environments, and moving parts like turbine blades must not harm fish and other species. And there’s always the risk that a rare endangered species could doom an entire project.
Furthermore, the Atlantic and Pacific coasts host massive animal migrations every year, from birds to whales to great white sharks.
All these factors and many more will loom large with ocean-energy projects in the U.S.
America’s coastlines are a unique combination of priceless landmarks and economic lifelines. Installing mechanical devices off these coastlines can raise all sorts of thorny concerns, such as:
- Property values in coastal residential areas.
- Livelihoods of people working in coastal fisheries.
- Safety of shipping and recreation in the proximity of marine energy devices.
- Conflicting agendas of local, state and national leaders.
In short, ocean-energy projects pass muster with a nation that prizes its ocean views and protects its ocean resources.
Opportunities in Obstacles
At PMI, we’ve been supplying high-performance cable-accessory gear to the energy-development industry for decades. Marine renewables are like any energy source — they have to be developed in the most practical, economical way possible.
Sure, there are tough challenges to be figured out, but the history of people finding opportunities in obstacles is too strong to ignore.
Offshore wind in the U.S. got a nice boost in June when the U.S. government announced that 81,130 acres off the coast of New York will be opened to leasing for offshore wind power projects.
Commercial offshore wind providers will have an opportunity to bid for leases they will need to develop wind farms in an area 11 miles south of Long Island. Although the U.S. does not have a single offshore wind farm up and running right now, the first project is expected to be operational by the end of 2016 and many more are on the way.
The U.S. Bureau of Ocean Energy Management has already awarded 11 commercial offshore wind leases worth $16 million and covering more than a million acres of U.S. waters, according to the BOEM website.
Nine of those leases have been sold through competitive bidding: Two each in New Jersey, Massachusetts and Maryland; two for an area between Rhode Island and Massachusetts; and one for Virginia.
Offshore wind power has a long way to go in the U.S., especially compared to Europe, which has over 3,000 wind turbines up and running. But U.S. several projects are in the works:
- A pair of six-megawatt wind turbines is proposed off the coast of Virginia. The BOEM has awarded a research lease for the project and approved a research action plan in March.
- An offshore wind project planned for Maryland could install as many as 125 turbines. It’ll still be a couple more years before construction starts, and two more years after that to complete the project.
- A more preliminary project is slated for the coast of New Jersey. That project is only in the opening stages. U.S. Wind, headquartered in Boston, is developing the New Jersey and Maryland projects.
- Another New Jersey project is being developed by Fishermen’s Energy, which won a Department of Energy grant to start a demonstration project near Atlantic City.
- DONG Energy, a Danish company that has done large projects in Europe, acquired the rights last year to develop a wind farm about 25 miles off the shore of Martha’s Vineyard.
The bottom line is that offshore wind will at least have demonstration projects up and running by the end of this decade to establish what works and what doesn’t.
The slow pace of adoption in the United States may frustrate advocates of renewable energy, but it’s important to remember that there was a time not so long ago when there were no wind farms in Europe. If oil prices jump and the political climate changes in ways that make offshore wind more attractive, we could see a lot more wind-power projects popping up off American shores.
After all, the technology is mature, thanks to the experience gained building Europe’s wind-power systems. A lot could change very quickly if all the right factors come together at the same time.
Companies that feel like they’ve missed the boom in offshore wind power technology may have the chance to ride a new wave of innovation with the rise of marine energy technology.
Converting the solar and kinetic power of our oceans into cheap, practical electricity seems like a far-off hope right now, but at some point the temptation to dive deep into marine energy methods and devices will prove too irresistible to pass up.
That’s something we’re watching closely here at PMI. Supplying equipment to companies that work in the oceans is what we do. Estimates suggesting the earth’s oceans could theoretically supply up to four times the world’s total electricity demand have definitely grabbed our attention.
Admittedly, it’s unlikely the oceans will ever supply all of humanity’s energy needs. But marine energy can become part of a diverse portfolio of renewables technologies like solar, wind and geothermal that serve the world’s energy needs while reducing carbon output and limiting global warming.
Looking Back on the Rise of Offshore Wind
It’s helpful to step back and look at how quickly offshore wind power became a mature technology in Europe. In 1990, there were no offshore wind farms in European waters. At the end of 2015, more than 3,000 offshore wind turbines were up and running, according to the European Wind Energy Association.
How many people could have projected that kind of growth in, say, 1980?
Obviously, nobody knows what the future holds. Marine energy is extremely expensive to develop and difficult to deploy right now. But it might not always be.
Potential Products and Devices in the Marine Energy Sector
European companies are already developing turbines and other devices to generate power from ocean tides and waves. These are big, expensive technologies that require substantial investments of time, energy and expertise. The companies working on them hope to exploit first-mover advantage and export their technologies worldwide.
As a supplier of subsea cable management systems, we see some interesting possibilities as these technologies emerge:
- Attachment points: One of the big challenges with marine energy is fixing devices to the ocean floor. Connections must be strong enough to hold energy devices in place and built to fend off the corrosion of saltwater. And they must be unobtrusive enough to have low impact on the undersea environment.
- Underwater vehicles: In an age when self-driving cars are already on the roads of Silicon Valley, it’s easy to envision rising demand for small submarines that can be put to work monitoring, repairing and maintaining marine energy devices.
- Pipe joints: One intriguing technology combines cold water from deep in the ocean and warm tropical water at the surface and creates electricity by exploiting the temperature differential. Called ocean thermal energy conversion, or OTEC, this technology requires pipes as long as several kilometers. Flexible pipe joints can help these pipes survive in ocean currents.
This list barely skims the surface of the possibilities in this sector.
Where the Marine Energy Sector is Going
Wave and tidal energy are getting the most attention right now. Costs for commercial development are still too high for this technology to become mainstream right away, but an encouraging collection of pilot projects in Canada, Europe and Australia — combined with the work of companies developing marine power devices — could lead to discoveries that can bring these costs down and encourage further development.
At PMI, we build accessories that make it easier to use cables in the ocean. Given that all marine energy devices have to transmit electricity over cables, we’re excited about the potential of marine energy.
But we also think that companies in a broad range of industries should be exploring these technologies and looking for ways to bring new products to market. If history is any guide, the people who invent the technologies that move marine energy into the mainstream stand to be forerunners of the industry.
Four intriguing technologies hold the potential to tap into the vast renewable energy of our oceans.
Nobody expects these marine energy technologies to replace coal, petroleum or natural gas in the near future. Instead, they could become assets in a diverse portfolio of technologies that can reduce our dependence on fossil fuels and temper the effects of climate change.
Let’s take a quick look at these marine energy conversion technologies.
The natural up-and-down motion of ocean waves generates large volumes of kinetic energy. Wave energy devices capture this motion and convert it into electricity.
Some wave energy devices look like ocean buoys that bob up and down. Others string together a long, snake-lake chain of floating tubes. They can work close to land or farther out in the open ocean.
Wave energy is plentiful, but it’s also problematic. Waves rise and fall in multiple directions, and their velocity changes with the weather. That can make it difficult to get a reliable constant stream of energy. Also, only a few coastlines are optimal locations for wave-energy devices.
The upside is that several prototype wave energy devices are already in the water, and they’re yielding clues on how to make wave energy more practical.
Rising and falling tides generate substantial kinetic energy. The bigger the tide, the bigger the power potential. Tides rise and fall like clockwork, so tidal energy can provide a reliable stream of energy at specific times of day.
Some tidal devices look like underwater wind turbines. Because water is so much denser than air, the turbines can turn relatively slowly and still produce a worthwhile stream of electricity. Another tidal technology creates dams that capture tidal waters and uses turbines to tap the flow, much like hydroelectric plants.
Tidal energy’s impact on the subsea environment is a big unknown. Marine species may attach themselves to the devices, causing extra maintenance costs. Building tidal basins is expensive and disruptive as well. And large numbers of subsea turbines can affect the velocity of tides, which could shake up delicate undersea ecosystems.
Salinity Gradient Energy (SGE)
Salinity gradient power exploits the energy produced when saltwater comes in contact with freshwater.
The technology uses a membrane to separate saltwater from freshwater. One kind of SGE membrane generates an electrical current on its own, while another kind of SGE membrane produces pressure that can turn a turbine and generate electricity.
These membranes anchor the technology. They must be extremely large to produce abundant volumes of energy. Right now they are very expensive and prone to fouling by algae and other aquatic life, but new companies are already trying out new membrane technologies. Innovations in nanotechnology could potentially make SGE economically viable.
SGE could also work in wastewater plants to separate saline water and create electricity to help power the plant. That small-scale function could open the door to more substantial innovations that make the technology much more practical.
Ocean thermal energy conversion (OTEC)
Water at the ocean’s surface is much warmer than water in the murky depths. OTEC uses this temperature gap to produce electricity.
A complex system pumps water from up to a mile deep in the ocean. At the surface, a power station exploits the differences between hot and cold water to produce electric current. This requires no fossil fuel, and it can generate more energy than the pumping and production costs create.
This technology works best in the tropics in areas where there is at least a 36-degree F (20 degrees C) difference between surface water and deep water. It also requires massive pipes to pump the cold water up. But the energy is extremely cheap once the power plant has been built, so it’s an intriguing option in a few specific areas of the globe.
Why We Like the Potential of Marine Energy
At PMI, we have no illusions about the challenges of marine energy conversion. But we still think companies everywhere should be paying more attention to these technologies. In Europe, there’s a strong push to get 20 percent of the continent’s energy from renewable sources by 2020. That creates an incentive for a few bold pioneers to get more prototypes into the water and see how they perform.
Those incentives could create opportunities for companies that have specific expertise. PMI is just one example: We already provide some of the world’s most advanced accessories for the subsea cables that all of these technologies will need to transmit electricity to land.
Marine energy technologies will require advanced engineering to make them cost-competitive with fossil fuels. They’ll also need advanced materials designed specifically for subsea environments.
That looks like a wealth of opportunity for innovative firms that can help bring these technologies into the mainstream.
Turning our oceans into a reliable power source means putting complex devices in treacherous, ever-changing environments. The sea is much friendlier to sharks than to subsea power turbines.
PMI has been providing cable hardware for oil exploration and other subsea projects for decades, so we know only too well the challenges of putting anything in the ocean and expecting it to keep working. Salt water is extremely corrosive. Many materials are extremely vulnerable to corrosion. Subsea organisms attach themselves to devices and reduce their effectiveness. Storms create chaos.
Marine energy devices can have lots of moving parts, take up lots of space and become part of the subsea biome. These are all things marine energy companies will have to confront as they build out the marine energy sector.
Here are some of the challenges we’ve noted in our research on installing and maintaining marine energy devices.
Physical Equipment Considerations
High-strength synthetic rope termination: Steel cables that fix marine energy devices in place are extremely heavy. An attractive alternative is high-strength synthetic rope, which often has the strength of steel but substantially less weight. You don’t tie knots in this kind of rope to attach it to devices. You use termination hardware, much like the hardware PMI builds for steel cables.
Mooring lines: Wave energy devices move with the motion of waves and use technology to convert the kinetic energy in moving waves into electricity. Typically, mooring lines are fixed in place. Allowing them to move with waves creates a host of challenges.
Large-diameter pipe bending: An intriguing marine energy technology called ocean thermal energy conversion, or OTEC, requires large-diameter pipes that could be up to several kilometers long. The trouble with these pipes is they are rigid and prone to bending because of relentless movements of ocean waters. The solution is to add flexible joints to these pipes that work much like the expansion joints in bridges — giving the pipes more flexibility and extending their life.
Small installation windows: Just as there are monsoon seasons on land, there are hurricane and typhoon seasons to deal with at sea. And even after these seasons fade, rough weather limits the time window for installing marine energy devices and fixing problems that crop up afterward.
Emergency retrieval: If a marine energy device breaks down or malfunctions in a way that presents an environmental threat, it may have to be retrieved as quickly as possible. This could require commissioning a ship and crew to retrieve the device on short notice, which can be extremely expensive.
Cable-laying methods: Cable-laying technology is mature and efficient, but it’s also extremely complex, requiring people who know how to deploy cable in ways that reduce the threats from ship anchors and submarine landslides. And the more cables get installed underwater, the more complex cable laying and maintenance becomes. Damaging an existing cable while trying to install a new one will be a persistent risk.
The rough terrain of the seabed presents another challenge. These high-energy environments have long been avoided because of the challenges they present, but now we must overcome those challenges in order to harvest the energy.
Biofouling: Algae, protozoa, and many more aquatic species attach themselves to the exterior surfaces of everything that goes underwater — anchors, ropes, pipes and marine energy devices themselves. Biofouling has to figure in any maintenance plans marine energy developers devise.
Device anchoring: Devices like tidal turbines that are installed on the ocean floor have to be anchored. Some anchors require drilling into the seabed, which can threaten delicate undersea environments. The challenge is to design and install anchors that have the lowest environmental impact while still being rugged enough to survive for decades in the ocean.
Unique and demanding terrain: Coastal topography varies widely from one continent to the next, so technology that works fine off the coast of France might be useless off the coast of Japan. This challenge holds worldwide: Tidal energy requires large tidal movements. Wave energy requires consistent wave movements. All these variables make it difficult to create technologies that can be standardized and scaled to reduce installation and maintenance costs.
What We See on the Horizon
At PMI, we already supply some of the world’s most advanced subsea cabling hardware, so our technology is poised to help address some of these challenges. Things look good to us right now, and the future looks even more promising.
As Europe pushes to get 20 percent of its energy from renewable sources by 2020, there will be social and political pressure to develop technologies like marine energy. That should create ample opportunities for companies to dip their toes in the water of marine energy technology.
Marine energy is a beguiling concept because our oceans have massive energy potential. Oceans can produce kinetic energy and store solar energy, both of which can be converted into electricity to replace fossil fuels that contribute to global warming.
But surface water on our planet also produces significant challenges: it’s turbulent, corrosive and teeming with life. Coastal areas are pivotal to local economies. Developing marine energy devices to tap the energy of the world’s oceans is rife with difficulties that boil down to six pivotal concerns.
Cost of Development
There’s no way to avoid the huge costs of developing first-generation marine energy technologies. For instance:
- Scientists must get funding to develop and test hypotheses.
- Engineers must find practical ways to convert research findings into effective mechanisms.
- Prototypes must be developed using components that can withstand brutal ocean environments.
And all this must happen before moving to the manufacturing process, which imposes a new set of development costs.
Legal and Regulatory Hurdles
Oceans are shipping lanes and fisheries. Coastlines are prime tourist destinations. Waterways play a huge role in economies around the world, and all economies have legal and regulatory challenges.
These are the complications entrepreneurs have to think about before they wade into the uncharted waters of marine energy development. They’re reluctant to pour a lot of time, energy and money into projects that could get mired in litigation and regulation.
It’s one thing to bring a new car factory to town with the potential to create thousands of jobs. Marine energy device developers can’t make those kinds of promises.
Also, marine energy is so new that few people at the political level understand its potential. That makes it difficult to rally voters who can lean on politicians to encourage marine energy development.
Also, public subsidies for renewables development can become extremely controversial if voters decide they haven’t gotten a good return on their investment. Because all politics is public, developers might not want to see their names in the headlines if their projects become a political liability.
The public also has no idea of the potential for marine energy devices, so it’s hard to tap a deep vein of public popularity to encourage investors and entrepreneurs to enter the sector.
Furthermore, devices could be installed in places where the public can see them and object to changes in their favorite scenic ocean views. And they might wonder about what will happen to our oceans if we install these devices in them.
All waterways are delicate ecosystems that are easy to knock out of balance. Installing rigid metal devices on the sea floor will create artificial reefs that could lure invasive species that have a survival advantage over the animals that are already there.
Devices also generate sounds that can affect some subsea species. The spinning blades of subsea turbines can potentially kill or injure fish and aquatic mammals.
Large numbers of devices in the water might also interrupt the migration patterns of fish and mammals, tripping up local fishers that depend on them for their livelihoods.
Levelized Cost of Energy (LCOE)
Levelized cost of energy (LCOE) is a complex calculation that can be used to compare the cost-effectiveness of competing energy sources. For instance, the LCOE of offshore wind installations is about two-and-a-half times higher than land-based wind power, according to the U.S. Energy Information Administration.
Post renewable energy sources have substantially higher LCOE than natural gas or coal, and some estimates say that marine energy devices have a LCOE as much as double that of natural gas or coal.
All of these challenges await anybody who ventures into the marine power device sector. The risks are large, but the rewards of devising technologies that can free us from fossil fuel dependencies could be even bigger — especially to those who come up with the most transformative devices.
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It’s one thing to dream about the immense power residing in our planet’s oceans. It’s quite another to put human ingenuity to work tapping into the ocean’s powers.
That was the backdrop of the International Marine Energies Technologies Course, held in mid-March in The Netherlands. Some of the best minds in marine energy technologies gave presentations covering intriguing innovations in the sector. PMI was the only U.S. company attending the course.
At PMI, we’re fascinated with the potential of marine energy. We supply cable hardware to companies that do business in the deep sea, including seismic exploration firms that tow massive cable arrays to hunt for petroleum deposits below the ocean floor. Since we’re experts in hardware that can survive treacherous undersea environments, we’re eager to contribute to initiatives that tap the energy of our oceans.
Europe has a huge head start on marine renewable energy technologies. Offshore wind farms are now mainstream technologies along the coasts of many European nations. With that technology well understood, European companies are starting to look at other ways to draw energy from the ocean.
The course covered four technologies:
- Ocean thermal energy conversion (OTEC). This technology taps the massive amount of solar energy trapped at the surface of the ocean in the tropics. OTEC uses warm sea water to convert a liquid into steam that drives a turbine, producing electricity. After the steam passes through the turbine, it gets cooled by water pumped up from the ocean depths, condensing it back into fluid form to continue the cycle.
- Salinity gradient power. When fresh water bodies are near salt water bodies, there is a substantial energy potential that can be harvested. Through pressure retarded osmosis or reverse electrodialysis, electricity can be generated. Salinity gradient technologies are being developed in Norway and the Netherlands.
- Tidal power. The ebb and flow of ocean tides can generate substantial kinetic energy that can be converted into electricity by several kinds of technologies. Tidal energy depends on the velocities water moves. (See Massive Tides Invite Wave of Tidal Energy Research for more).
- Wave power. Where tidal relies on the velocity of water, wave power relies on the change in height of waves to harvest energy. (See Scotland’s Sunken Wave Turbines for more).
Each marine energies technology has pros and cons. While all can produce energy without the use of fossil fuels, they also face substantial challenges because of the chaotic and corrosive nature of oceans. Furthermore, they require substantial financial investments and must offer some hope of providing a return to investors.
Moreover, any devices placed in the ocean are entering an active ecosystem that must be protected. The sessions of the International Marine Energies Technologies Course addressed these challenges. The people attending included engineers, researchers and representatives of companies venturing into the emerging ocean-energy field.
So what was PMI doing in Holland for three days? Well, we supply cable hardware to companies that do business in the deep sea, including seismic exploration firms that tow massive cable arrays to hunt for petroleum deposits below the ocean floor. It’s a great business to be in, but we also recognize the necessity to tap into renewable energy sources in the years to come.
Since we’re experts in hardware that can survive treacherous undersea environments, we’re eager to contribute to initiatives that tap the energy of our oceans. Ocean energy technologies are barely off the drawing boards in the United States, but our European colleagues are getting devices in the water and starting to generate energy.
And that’s getting us energized about the power of our oceans.
Want more information about our experience at International Marine Energies Technology Course? Schedule to speak to a representative.