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
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.
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…)
