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.
Wave Energy
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.
Tidal Energy
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.
Logistical Challenges
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.
Environmental Issues
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.
Political Support
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.
Social Support
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.
Environmental Concerns
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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Fundy Bay is famous for pictures of fishing boats tilted on their hulls — run aground by the immense power of the world’s largest tides.
The waters of this scenic coastal inlet along Canada’s Nova Scotia and New Brunswick provinces rise and fall by more than 50 feet twice a day, every day of the year. That predictability is one of the key reasons why green-energy researchers are fascinated with the potential of converting tidal movements into electricity. Solar power goes dark after sunset and wind power rises and falls with moving weather patterns. But tides rise and fall like clockwork, creating the potential for an extremely reliable stream of electric power.
The Trouble with Tidal Energy
Unfortunately, the ocean is one of the worst places on earth to install mechanical equipment. Saltwater is extremely corrosive, and working on machinery underwater is incredibly dangerous and expensive.
Some wave and tidal energy projects are mounting turbines on the sea floor. This keeps the turbines out of sight, which is a boon to coastal views, but it also dramatically increases the costs of upkeep precisely because they are so difficult to access.
Floating Platforms: A Tidal Energy Alternative
Fundy Bay’s epic tides have made it a hub for working out these kinds of challenges in wave and tidal energy research. One alternative researches are exploring is mounting a turbine beneath a floating platform that’s moored to the ocean floor via cables. A turbine connected to a floating platform could have all of its machinery easily accessible from the platform rather than mounted on the sea floor, where the only way to reach it is with scuba divers or remote-operated vehicles (or both).
In March 2016, a Canadian firm called Dynamic Systems Analysis (DSA) helped launch a floating research platform called EcoSPRAY that will document how highly turbulent tides work. This, in turn, will provide clues to the best ways to deploy floating tidal energy platforms that have been moored to the ocean floor.
The platform is operating in the Grand Passage between Freeport and Westport, Nova Scotia, in the Outer Bay of Fundy. Sensors on the EcoSPRAY will track wind speeds, tidal currents and wave actions. A drag plate mounted on the bottom of the platform will simulate the thrust of an underwater turbine, DSA says.
Protecting tidal ecosystems
While floating tidal power platforms would be less visually pleasing than turbines mounted on the sea floor, they have the potential to be less disruptive to underwater environments. Mounting an underwater turbine is a major construction project, whereas placing anchor points on the sea floor for mooring cables could be far less disruptive to the coastal environment.
Protecting that environment is very much on the minds of Fundy Bay researchers. Fundy Ocean Research Center for Energy (FORCE), the Offshore Energy Research Association (OERA) and the Nova Scotia Department of Energy are all working together on a half-million-dollar program to determine the effects of tidal energy turbines this year.
This points to the future of wave and tidal energy, which may well depend on finding the best mix of high energy output, low cost and minimal impact on the subsea environment.
Related articles:
• EcoSPRAY tidal platform inspects moorings in high-tidal flows
• Fundy tidal energy study to look at seabirds, lobster, acoustic environment
Learn more about our Tidal and Wind Energy Efforts today:
The coast of Scotland has some of the world’s strongest waves, which makes it a vital testing ground for wave turbines that convert wave movements into electricity.
So it’s no surprise that the Pentland Firth region of the Scottish coast is the site of the $1.5 billion MeyGen turbine project, where offshore cables are being laid in the opening phases of an initiative that aims to install 279 wave turbines below the surface of the ocean. As a recent Quartz.com report noted, the project could provide up to 400 megawatts of electric juice that could power 175,000 homes.
The wave-power turbines look much like wind-power turbines. Moving waves turn the turbine blades, generating electric power. Some observers say wave-power technology is about three decades behind wind power. But the MayGen project could signal the arrival of wave technology power, once it gets up and running.
Wave power technology is taking a wide array of shapes. Some devices look a bit like mechanical eels floating on the surface of the water; others are more like paddles that flow back and forth with the waves, moving a piston that generates power.
The ocean is an alluring power source, because it is so much denser than air and can therefore generate far more movement that can be converted into electricity. But even with 800 times more density than air at the surface, the water in the ocean creates an extremely problematic environment for energy development.
A recent Wall Street Journal article pointed out severity of the challenge:
“People say this is not rocket science,” says Neil Kermode, managing director of the European Marine Energy Centre. “No. You fire a rocket into a nice, cold vacuum. We’re trying to do things in a salty, grit-filled electrolyte that’s got animals in it.”
Indeed, waves flow in multiple directions, unlike the wind, and the undersea environment could potentially be damaged by these kinds of projects. These and other factors vastly complicate wave-power generation.
Right now, cable-laying equipment is installing the offshore cables that will convey power to the people of Scotland after the wave turbines are up (well, down) and running. While power cables may not seem as exciting as subsea turbines, they still represent one of the most vital components of the project.
As wave power advances, PMI will be poised to provide durable ocean cable hardware to help these kinds of projects succeed. We have the experience and knowhow to design and manufacture rugged cable accessories that can last for years in the most difficult ocean environments. As the energy world transitions from fossil fuels to renewables, PMI cable hardware will be there every step of the way.
Elsewhere on the PMI blog: Tidal and Wave Energy Industry Struggles With Harsh Ocean Environments
Related article at Environment360 published by Yale University: Will Tidal and Wave Energy Ever Live Up to Their Potential?
Need some tips on how to extend your subsea power cable life? Check out our guide:
Subsea power grids require two major kinds of ocean equipment: subsea power cables to convey electricity to the grids, and generating equipment to distribute electricity to pumps and other devices required to find and extract crude oil.
Even in a time of depressed petroleum prices, oil companies still value deep ocean engineering and they like the prospect of placing power grids on the sea floor because the grids improve the efficiency of the extraction process, which helps hold the line on production costs. When the oil market inevitably rebounds, companies with the most efficient production processes will reap the greatest rewards.
Let’s look at some of the ocean hardware that will go into these subsea systems:
- Transformers: These take power from the surface — either from the mainland or a floating platform — and convert it into the voltage needed at the undersea grid level.
- Switch gear: Switches adjust the flow of electricity to the deep-sea components that need it. If a pump needs different voltage than a compressor, switch gear takes care of that job.
- Variable-speed drives: An oil-drilling pump needs to run at multiple speeds to achieve maximum efficiency. VSBs make this happen.
- Cables: Cables carry energy from the surface to the grid and distribute it to the transformers, switch gear, variable-speed drives and any other ocean hardware in the grid.
Why deep-sea power grids are so attractive
Oil drillers need a lot of power to extract oil from below the deep sea. A deep-sea power grid allows power to be distributed to dozens of pieces of subsea hardware across a wide expanse of the sea floor.
A site developing a deep-sea oilfield becomes much easier to operate if power sources are on the sea floor near the point of extraction. Without a grid, power can be sent down via cables to equipment within a very limited expanse. A grid dramatically expands the area of sea floor that has available power.
Challenges for deep-sea equipment
Companies are designing subsea grids that can operate for up to 30 years in up to 10,000 feet of water. That places immense pressure on the equipment and requires precise engineering to protect delicate electrical components.
Saltwater is extremely corrosive, and undersea creatures like to attach themselves to any structures they can find. Fishing fleets drag deep nets that can become entangled in deep-sea equipment, and ship anchors have the potential to damage or cut subsea power cables.
Robust ocean equipment is the answer
Subsea energy companies understand the extreme terrain and know they need to build robust gear to provide reliable systems that can last decades. That also means they need to rely on proven ocean hardware that is high quality, highly reliable and fully flexible.
Offshore renewable energy solutions might be new to the world, but we know that all ocean equipment requires deep ocean engineering experience. And for over 60 years, PMI Industries has provided ocean hardware that increases efficiency, reduces failures, and improves installation and deployment time.
Waves and tides offer some of the most predictable, consistent, and just generally big energy resources available. However, rollouts of actual wave and tidal energy power installations have been slow. Part of the reason for this is that there is no consensus at all on what represents the best device designs to actually harness waves and tides and therefore on what subsea equipment is necessary to use.
Any subsea equipment needed to harness tidal energy is going to be expensive – and will tend to drive building costs to be anywhere between 3 to 15 million dollars and sometimes more. But in the long run, the investment will pay off.
Now the pros and cons of tidal energy always bring debate – but tidal energy has a lot going for it:
Consistent Power – Tides move constantly throughout the day, which provides a consistent stream of electricity generation capacity.
Pollution-Free – By taking advantage of only the tide, tidal power creates no greenhouse gas emissions or water pollutants.
Renewable – No material resources are used or changed in the production of tidal power, making it a truly renewable power form.
Minimal Visual Impact – Tidal power devices are fully or nearly completely submerged in water well offshore. This reduces the “damaging of water views” that has been associated with offshore wind turbines.
Efficient – Tidal Power converts roughly 80% of the kinetic energy into electricity, as opposed to coal and oil which convert only 30% of the energy held within.
Locations – There are numerous locations for tidal power around the world. Other websites online have this number at 40, however the coast of British Columbia, Canada has 89 alone.
And most importantly it offers low operating costs – Once installed, there are few ongoing operating costs or labor costs. By making investments at the forefront and building these systems properly with reliable equipment, tidal energy power plants offer a long lifespan, ultimately reduce costs, and make tidal energy more cost-competitive in the long run.
Whether they are lifting oil from deep below the seabed or experimenting with data centers on the ocean floor, anybody getting work done below sea level lives in perpetual fear of subsea equipment failures.
This is especially true as oil-development machinery equipment installed decades ago reaches the end of its projected operating life. What do you do with 20-year-old machinery that was built to last 20 years? Replace it now or wait for it to fail?
Either way, it will not be cheap. How can companies mitigate the risk of subsea equipment failures? A few tactics spring to mind:
Dive deeper into predictive maintenance
With today’s high-powered computers, databases, and networks, it’s getting much easier to collect data that will provide authoritative data on the likely expiration of subsea equipment. Of course this requires sensors that measure the conditions of equipment, and cabling to convey all that data to the surface.
It’s not an easy or a quick fix, but it should be built into any process of replacing or upgrading any new equipment being installed now. Forward-thinking drillers who do this today will reap far more benefits when oil prices inevitably recover.
Invest in more in-depth training
Subsea equipment fails for highly specific reasons that might be invisible to people who make routine checks and are trained to look for only a few data points. The key is to amass the knowledge of your most senior technicians and develop protocols to pass their advanced knowledge onto your junior technical staff.
Again, the oil market downturn can be a boon to advanced training because you can provide more in-depth training to smaller technical staffs. When repair and maintenance crews have to be ramped up in a year or two, you can implement your advanced training regimen to a wider audience.
Broaden your approach to integrity management
Integrity management has three anchors: inspection, maintenance and repair (IMR). You want to address all three holistically so that any change in one anchor is reflected in the others.
Deep-sea inspections can be logistically difficult and repairs can be disastrously expensive. That’s why so many companies are turning to data to help them understand the likelihood of failure so they can get every last minute out of a piece of subsea machinery but replace it before it actually fails and causes massive downtime or, worse yet, an environmental disaster.
There’s no question that all phases of IMR are costly, but the consequences of neglecting IMR are far worse. There will always be a temptation to cut corners on the quality of your subsea equipment, but these short-term savings can get extremely expensive if the equipment fails unexpectedly, endangering investments, ecosystems and people’s lives.
As a leading underwater engineering company, PMI has more than four decades of experience in creating subsea hardware for the oil and gas industry. Our track record of providing world-class cable hardware also can be a huge advantage companies in the emerging fields of offshore wind and tidal energy.
Want to learn more about deep-sea hazards? Download our Free Guide – the 6 types of corrosion that concern underwater engineering companies.
The island nation of Iceland has more renewable energy than it needs. Great Britain wants to use more power from renewable sources. A 1,000-kilometer submarine power cable could conceivably help Iceland export its surplus renewable power and help Great Britain meet its renewables goals.
All this is possible because of the advantages of high-voltage direct current (HVDC), which makes it more practical to transmit power over long distances via submarine power cables. Electrical grids around the world generally use alternating current (AC) because it’s more economical over short distances.
The problem with AC is it becomes less practical the farther the power has to be transmitted. When power has to be transmitted distances in measuring in the hundreds of kilometers or more, it becomes much more sensible to use high-voltage direct current.
Using HVDC to move lots of power over long distances is extremely helpful in developing nations like China that have rapidly emerging energy demands. But another of the great opportunities for HVDC lies deep below the ocean with subsea power cables.
Long-distance subsea power cables have a host of applications:
- Windfarms located far offshore. Wind is more abundant far away from shore, and many near-shore sites have already been developed. Submarine power cables using HVDC make these remote windfarms practical.
- Subsea electrical grids. Electrical grids beneath the ocean are being developed to improve the productivity of off-shore drilling operations. HVDC could allow them to be powered by production facilities on dry land.
- Metro areas where it’s impractical to build new power plants. In the San Francisco Bay Area, for instance, subsea power cables can extend power across the bay and avoid the need to build new power generating capacity.
This potential sounds awesome until you hear the statistics on how long it takes to repair a damaged submarine power cable. It can be days, weeks or months depending on the location and the severity of the damage.
The rugged reality of deep-ocean engineering is that it only takes one fishing trawler or cargo ship anchor to foul up a deep-sea power transmission plan. That’s why subsea cable protection is so important.
Providing that kind of protection has kept PMI in business for more than four decades, engineering rugged, durable ocean hardware for companies and projects around the globe.
Our deep ocean engineering experience helps enable the world-changing potential of renewable power. No matter how breathtaking the advances in technology, if the power has to be sent through subsea cables, those cables need extra protection that our ocean hardware provides.
Our guide, 6 Ways to Extend Your Subsea Power Cable Life, can provide more insight into increasing the longevity of your subsea cables. Download the free guide today:
