New wind farm designs can power the grid
New off shore wind technology can provide baseload electricity:
Imagine a future where renewable energy comes from winds so strong and so constant, that it can replace what’s known as base-load power.
Ensuring the availability of base-load (always available) power to customers is critical to the historically conservative utility industry. There has, therefore, been a reluctance of some officials to more fully embrace renewable power. The conventional thinking has been along these lines: “How can reliable base-load power be delivered when the sun doesn’t shine and the wind doesn’t blow?”
One answer: several new off shore farm technologies which promise to significantly boost the delivery of stable base-load power to the electrical grid.
Far off shore, in the deep seas- winds blow near constantly- and with strong force. For quite some time, conventional wind turbines- strengthened for deep sea use- have been off shore in the far out of sight deep waters. A good deal of these ocean wind farms are operating in northern Europe. A few deep water wind farms have been planned for the United States, but the uptake has been slow. Previous plans called for turbine placement closer to shore – however, a close-to-the-coast wind farm in New England had stalled for many years due to neighbors’ concerns regarding sight lines.
Additionally, far offshore deep water wind power has faced a number of technical obstacles – it’s notoriously difficult to develop, it’s costly, and it’s difficult to maintain. However, we’ve chosen to focus on two technologies which aim to change that paradigm, and make practical the installation of large scale off shore wind farms.
Offshore Multiple Turbine Platform
One promising technology is being trialed by the European firm Hexicon, and its approach is simple:
Rather than one-by one labor intensive single installations, build two or three rotating wind turbines on one anchored platform- which can be built and operated rather like a conventional offshore oil rig.
Hexicon claims there are additional benefits to a platform based solution. The upside to platform basing includes longer life, reduced wind farm sea cabling (fewer far apart turbines), and easier/ safer maintenance access.
Additionally, the platform can be simply towed back to a shipyard for refits if necessary. Other energy technologies can be placed on the platform, such as wave, tidal and solar power. The platforms can even be used for fish farms!
- Multi Turbine installations provide scale of economy, and the platform becomes more competitive than stand-alone concepts. This features offers a developer to install more MW in the same concession area than what is normally the case.
- Hexicon platforms turn automatically into the wind for optimal efficiency. The ability to turn the platform gives each turbine free and linear wind at all times. (This feature drastically increases access to more locations with best possible wind conditions).
- Throughout the platform, existing well proven marine technologies are used to build the platforms at shipyards in sheltered waters while installing wind turbines at the same time.
Hexicon’s platform is a great example of taking current turbine technology and leveraging it in a manner that makes deep water wind a more sound investment.
What about newer technology for the turbines themselves ?
The Segmented Ultralight Morphing Rotor (SUMR)
Rather than cluster somewhat conventional turbines, (the Hexicon example) is there a way to make a stand alone unit more productive and efficient? Government researchers are developing a significantly enhanced stand-alone turbine. In its energy research facility at Sandia Labs, the Department of Energy has been working on turbine blades that flex and fold.
The ability to flex in the wind is critical- because as turbine rotors and rigid blades increase in size – the weight increases. Extremely large and heavy rotors and blades make wind turbine installation (and operations) both difficult, and expensive.
The solution to this problem is based in nature. A palm tree bends and sways in the wind, but rarelybreaks. To emulate nature’s quite elegant solution, Sandia Labs’ blades are segmented. They will bend and turn with the wind- rather than simply be hardened against it. This type of design enables the blades to be lighter and larger- possibly the largest, most efficient wind turbine blades ever developed.
To power its notional 50 megawatt turbine Sandia has designed a segmented blade which is to be some 200 meters long, twice the size of Sandi’s longest current blade.
The following picture more clearly illustrates the Sandia concept- In high winds – quite dangerous to a standard turbine – Sandia’s morphing rotor completely folds the blades in, to come into an alignment with the wind. When only slightly folded, the blades efficiently generate power at lower wind speeds. (For a demonstration- see the animation at bottom of this post)
Why design such a large turbine? The largest in-production turbines are now some 8 megawatts. Getting much larger than that with conventional stiff blades is a challenge- and current technology will top out at 10-15 Megawatts. By going large and flexible, Sandia’s design could do the work of 5 to10 conventional installations. Fewer installations means less up front capital, shorter construction periods, and a smaller underwater cable grids. Ongoing, a farm with a small number of the larger, flexible blade turbines should also require fewer monitoring and maintenance trips out in the ocean.
Although early in the concept/ experimental stage, the morphing rotor/segmented blade is being developed in partnership with several research teams and wind turbine manufacturers:
The team is led by the University of Virginia and includes, in addition to Sandia, researchers from the University of Illinois, the University of Colorado, the Colorado School of Mines, and the National Renewable Energy Laboratory. Corporate advisory partners include Dominion Resources, General Electric, Siemens, and Vestas.
Deep Water wind farms can provide baseload.
In each of these cases it’s clear that by creating fewer, yet more powerful offshore wind power installations, cost savings can be substantial: Capital costs can be reduced – inspection and maintenance times – cut. Fewer stand alone wind power units also means laying fewer underwater cables – shortening the installation and wiring time. Such installation efficiency can mean a faster tie to the power grid, and, therefore, a quicker return on investment.
Off shore wind is a nearly “always on” source of power- Yet at times of extreme weather that abundant energy hasn’t been available in conventional turbine installations. By re-imagining the wind farm, and the turbine itself – offshore wind can be a clear and economical choice for the provision of base load power.
Based in the waters of the deep sea- these two innovative solutions may out of sight, but should certainly be kept in mind.