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:
We’ve gone in depth before on how cable terminations are used , now we’re going to explain what sets our terminations apart from the competition.
Many current terminations require an epoxy/polish method of installation. There are many disadvantages to using epoxy. If you’re using heat-cured epoxy, it takes a ½ to cure, but you need an oven to cure it. Room temperature epoxy doesn’t need a special oven, but the cure time can be 2-3 hours or more. When researchers are spending days or weeks out on the ocean gathering information, time is of the essence.
Other terminations on the market don’t use epoxy, but require specialized equipment to install or require extensive cable preparation before installation. In addition, many epoxy-less terminations have a higher connector cost.
PMI provides quality epoxy-less terminations for your ROV needs. Here are 5 that the EVERGRIP Helical Gripping Termination is your ideal solution:
- Faster Installation
The EVERGRIP termination is field installable and easily applied – usually in 30 minutes or less.
- No Special Tools Needed
Our product requires no additional tools or cable preparation to install
- Less Down Time
With the EVERGRIP, there is no need to wait for a termination/retermination to cure.
- Strain Relief for Cables
The special helical rod design relieves strain from the cable. We also have BSR solutions for additional strain relief to prolong cable integrity.
- Reuseable
The housing of EVERGRIP can be used – a Retermination Kit comes at a much lower cost than purchasing a new termination
As new challenges are placed on the ROV industry, PMI continues to provide new solutions to meet those challenges. Whether it’s greater strain capabilities, faster installation or higher cost savings, PMI has the capability to develop and supply the highest quality and reliability solutions.
To read more advice on choosing the best subsea terminations for your project, download our checklist:
7 Questions You Should Be Asking About Your Subsea Terminations
Offshore wind and solar energy have been getting all the attention in the quickly growing renewable energy industry, but there’s another player that is beginning to grow strength in the energy market – ocean waves and tidal currents, or “marine energy”. There are vast amounts of energy that are produced within the moving waters of oceans and rivers, and companies working to harness this energy are quickly gaining speed.
While not nearly as large as the main competitors in renewables, marine energy has strong advocates and is quickly gaining steam in the renewable market. About 30 tidal and 45 wave energy companies are at an advanced stage of technological development. One of the biggest issues these companies are facing that has impeded forward movement in the market is the harsh ocean environments – the same thing that makes the industry work in the first place.
The intensity of sea waves is greatly unpredictable and can cause damage throughout the process. Installation of the equipment is often difficult – the areas that are best suited to harness wave and tidal energy are often very hazardous and can be difficult to navigate. As we mentioned in our article on subsea cable vulnerability, subsea cables and hardware have to withstand 14.5 psi per every 10.05 meters they are lowered into the ocean. That coupled with the harsh environment that marine energy succeeds in, makes for a harsh environment for equipment.
PMI has many years of experience engineering proven subsea hardware for companies around the globe. We are excited to be part of the quickly growing marine energy market and are ready to create custom and quality solutions that will withstand harsh and hazardous environments.
Read more about the potential of wave and tidal energy.
The outcome of your project will rely on the quality of your subsea terminations. Make sure to download our guide – 7 Questions You Should Be Asking About Your Subsea Terminations – for a through breakdown of what you should be looking for in your subsea terminations.
As the energy market continues to turn away from oil and gas and towards renewable energy, many companies that specialize in deep ocean engineering, like PMI, are following suit. One company that has made great efforts to shift from oil and gas into the renewable energy field are the Norwegian subsea specialists Ocean Installer. The company’s advanced vessel, the Normand Vision, was used for work on subsea umbilicals, risers and flowlines (SURF) for major companies in the oil industry. Realizing that their subsea construction support equipment could also be used to work on the underwater cables that connect offshore wind platforms with the power grid, the Normand Vision began working with wind farms, including Germany’s Gode Wind 1 farm. Ocean Installer is not the only subsea construction company to jump on the renewable energy bandwagon. Singapore’s EMAS has also begun adding wind energy projects to their portfolio.
PMI shares the vision of these companies as our energy markets focus on new horizons and is excited to work with customers to solve their cable issues with budget friendly and top quality underwater cable hardware that will maintain cable integrity in every kind of underwater environment.
Read more about Ocean Installer and the Normand Vision.
To find out more about our custom ocean engineered cable hardware equipment, schedule an appointment to talk to our experts today.
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