Harnessing the wind to create a cleaner, greener world
Created by the rotation of the Earth itself, wind represents a virtually limitless source of energy. And when harnessed for electricity generation, it results in a net reduction in CO2 output of 90% or more over conventional power plants. Which means that for countries like New Zealand, it's a win-win proposition. And for companies like Olympus, it's a chance to put our technologies to work to help make the world a cleaner, greener place.
Tararua Wind Farm
Surrounded by the Tasman Sea and the Pacific Ocean, New Zealand lies across the latitudes that ancient sailors called the 'Roaring Forties'. It is a region where strong westerly winds created by the Earth's rotation circle the globe, racing across the open ocean unimpeded by any large land masses. These winds, which once drove clipper ships across the sea, are now helping New Zealand to meet its electricity needs, and to combat global warming by reducing its CO2 output and dependence on fossil fuel energy sources.
New Zealand is not alone in this effort to harness the wind. Around the world, wind power is assuming an increasingly important role in the task of electric power generation. Although wind currently accounts for only about 2% of global electricity output, that share has doubled in the past three years, and in countries such as Denmark, Spain, and Portugal, wind already accounts for more than 10% of electricity production. Over eighty countries currently generate some of their commercial power from wind, and worldwide wind generating capacity is growing at a rate of 20% per year.
In New Zealand, wind power already accounts for 4% of electricity production, enough to meet the needs of some 180,000 households, and this is projected to increase to 15-20% of total production over the next 20 years. A total of nine wind farms have been constructed so far, each consisting of multiple towers topped by large, three-bladed turbines and power generating units. The largest, in both power output and number of turbines installed, is known as the Tararua Wind Farm. Located in the Tararua mountain range on the north island of New Zealand, it currently consists of 103 turbines with an output of 660 kilowatts each, and 31 turbines with an output of 3,000 kilowatts each. The larger turbine assemblies are truly enormous, standing as tall as 90 meters (about 300 feet), with rotating blades as long as 45 meters (about 145 feet). To ensure safe, efficient operation, both tower and turbine must be strong enough to withstand high winds and the powerful force of rotational momentum, so structural integrity is essential.
And that's where Olympus comes in. Because through its technical support centers around the world, Olympus has become a major supplier of ultrasonic and remote visual inspection equipment used to help insure the structural integrity of everything from ships and aircraft to bridges and power plants. In the case of wind power turbines, these non-destructive testing and inspection systems help assure not only turbine blade manufacturing quality and structural integrity, but also the ongoing safety and power generating efficiency of turbines in service.
Wind power generator tower weld inspection
Wind turbine blades are usually fabricated by hand using multiple layers of fiberglass cloth. The cloth is cut to shape, laid down in a mold, sprayed or rolled with resins, and finally cured. It is a proven method that is often used to produce fiberglass boat hulls and lightweight car bodies, but it tends to result in small imperfections and variations in thickness that can cause wind power turbine blades to delaminate and fail prematurely. To discover such anomalies before problems arise, inspectors employ Olympus EPOCH ultrasonic flaw detectors and OmniScan phased array systems that use high-frequency sound waves to examine the internal structure of blades. Capable of penetrating up to 80mm of composite material, these advanced devices analyze reflected sound waves and provide inspectors with a readout that enables them to spot any weakness in the blades' critical internal bond lines.
Similarly, Olympus ultrasonic flaw detectors and phased array instruments can be used to inspect welded joints in the towers that support the wind power generators. Ultrasonic weld inspection is already widely used to identify hidden cracking, incomplete fusion, and other weld flaws on bridges and other large steel structures, and the equipment and technology can be readily applied to the towers that support the massive weight of wind power turbine and generator assemblies.
Wind power turbine gearbox inspection
The usefulness of Olympus ultrasonic and remote visual inspection equipment also extends to the Tararua Wind Farm's day-to-day operation. While some in-service inspections are carried out on the blades and tower, the most frequent periodic inspections are performed on the gearboxes in the generator. Torque loads on these gearboxes are typically very high, and gear teeth and bearings can fail over time. But inspecting them is no easy task because the generator housing at the top of the tower is barely big enough for one person to crawl inside. Given these adverse conditions, the only way to thoroughly inspect the gearboxes is to use a flexible videoscope such as the Olympus IPLEX, which enables engineers to see clear, magnified views of critical parts in spite of limited external access.
In New Zealand and around the world, we're always happy to hear that our products and technologies are helping customers to solve problems, increase efficiency, and reduce downtime. And we're especially delighted when those benefits also help them address the larger issue of global warming, and support the worldwide movement to adopt cleaner, greener, renewable energy resources.
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