Also, a detailed investigation is carried out for weaknesses or flaws associated with a particular type of wind turbine, such as known shortcomings in the quality management during specific production periods or certain components or design flaws that lead to premature defects. The conditions of the main elements of the turbine — i. The immediate shutdown of a turbine is recommended in the event of significant damage that would compromise the safety of continued operation.
In most cases, however, the damage discovered is relatively minor and caused by corrosion, weathering and material fatigue. For instance, rotor blades or cables frequently need maintenance. Close attention is also paid to any changes in the surrounding environment of a wind farm.
Expansions in neighboring sites must be taken into account in turbulence calculations. In the analytical part of the lifetime extension assessment, operating loads are compared with design loads. The results of the physical inspection are considered in these calculations. Fatigue loads are simulated using software-based models that take into account site-specific wind conditions as well as design conditions. All load-bearing components contributing to the structural stability of the turbine are examined: the tower and foundation, screws and bolts, load-bearing parts of the drive train, the hub, the shaft, the rotor blades, braking systems and the safety functions.
This report specifies the remaining time until design loads are reached. Based on the calculations, a statement is prepared highlighting immediate measures required for continued operation, as well as measures that become necessary at defined points in time, like exchange of parts or individual inspection strategies.
As long as wind farms are operated within their design lifetime and the design conditions are not exceeded, a defined safety level against the occurrence of damages caused by material fatigue is maintained. In many cases, wind conditions at the site result in lower loads than originally planned. Thus, the supporting structure of the turbine is often free from significant damage and the necessary repairs are generally minor and cost-effective.
A lifetime extension assessment determines whether continued operation is possible and assists managers and operators when planning for the future of their assets. The results of a lifetime extension assessment can also be used to plan maintenance shutdowns and to forecast the costs that are likely to be incurred during the remaining lifetime of a turbine.
They can produce more energy, meaning you need fewer of them, which saves money on transport, installation and servicing. Siemens Gamesa says 20 of its new 10MW turbines, announced last year with 94m blades, could power Liverpool, with a population of half a million.
But large turbines bring along their own challenges, including what to do with them when they are no longer needed. Bigger blades "need bigger factories, bigger vessels, cables, foundations, and handling equipment," says Ray Thompson, global business development head at Spanish-headquartered Siemens Gamesa, one of the world's two largest wind turbine makers. Longer blades can make for bigger recycling headaches, too. The composite fibreglass in blades is "the most difficult, and the most expensive part" of turbines to recycle, Mr Kragelund says.
And there's more of it. There's some reselling of second-hand turbine components from Europe to the Middle East and Asia pacific, he says.
Big data, leading to better maintenance regimes and more reliable components could also mean today's blades might last longer, says Siemens's Mr Thompson. Recycling has made more progress so far in the onshore than offshore industry, which is newer, he adds.
But while "there is work being done to find ways to recycle materials from old turbines," it "would be nice to see more design input now, so that's easier in the future," says Prof Cochrane. Image source, Global Fibreglass Solutions.
Turbines from the s are reaching the end of their working lives. Don Lilly of Global Fiberglass Solutions hopes to sell pellets made from recycled turbine blades. Pellets made from old turbine blades can be used to make new products. Wind turbine power is an infinitely sustainable form of energy that does not require any fuel for operation and generates no harmful air or water pollution-produces no green house gases and toxic or radioactive waste. In addition, the land below each turbine can still be used for animal grazing or farming.
Disadvantages of using wind turbines include the need for more land space to support a wind farm and the difficulty in having a location with enough wind to produce maximum efficiency and power Figure 3.
The placement of turbines in areas of high population density can also result in aesthetic problems. Other drawbacks include death of birds and bats due to collision with spinning turbine blades and turbine obstruction in their flight paths9' Studies are being conducted to improve turbine design so as to reduce wildlife contact and mortality rates.
In cold climates, ice and rime formation on turbine blades can result in turbine failure12 A heating system or a special coating of the blade's surface can reduce the risk of failure.
However, the potential for ice to be thrown great distances during windy conditions is a potential health hazard. A recommended safety zone area should be factored into the design specification to reduce public access, potential risks, and sound.
Wind speed is for standard sea- level conditions. Figure 3: U. Department of Energy DOE Annual Report on the development and trends of wind power reports that the cost of wind power is nearly very competitive with those of conventional power technologies. And this does not account for the environmental and health benefits of using a non-polluting source of energy.
It is expected that over time, wind energy cost will decrease as most conventional generation technology costs continue to increase.
Since , the cost of turbines has been on the rise because of increase cost of input material, energy prices, and in some cases, shortages in certain turbine components The cost of electricity produced from wind farms can be attributed to the annual capacity factor, location, wind quality, and installation and maintenance costs.
However, the cost per kW decreases as the size of the turbine increases. Wind availability at a site also influences cost. Wind turbines installed in very windy locations generates less expensive electricity than the same unit installed in a less windy location.
It is therefore important to assess wind speeds at the potential site during the planning stage See Figure 3. It is the second largest new resource added to the U. Wind turbines have been installed in 22 states, with Texas, California, and Iowa leading the nation in annual capacity growth And when the giant turbines come down, they can leave a lot of waste behind.
The steel towers can be recycled, but the fiberglass blades typically end up in landfills. The state of Wyoming has decided to nip this problem in the bud.
The Bureau of Land Management and Wyoming Department of Environmental Quality are working together to ensure that future wind farm projects are not abandoned.
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