The construction of wind power plants is becoming more and more challenging. Fortunately, batteries can help
July 24. 2023
Just as the share of wind in electricity generation is increasing, so is the number of wind turbines scattered across the landscape. And their size, which makes erecting these structures increasingly difficult. New approaches therefore rely on battery storage.
In 2022, wind power plants with a total rated capacity of 16,148 MW were newly commissioned in the European Union countries alone. In Europe at least, the vast majority of these are being built onshore, 92 percent in the EU. Building offshore wind farms is of course technologically and financially demanding, but erecting a wind farm on land is neither easy nor cheap.
The average cost of a single blade in 2022 was between €2.5 million and €3.5 million, and transporting wind turbine components to their destination is also expensive. It can require a year of planning and up to 10 loadings, so the average cost of transporting a wind turbine in Europe and North America ranges between 25 and 35 thousand euros, although long-distance transport can cost up to three times that.
Bigger and even bigger
The larger the turbines, the more complex everything is, from the design of the equipment, to the choice of site, to the number of vehicles needed to transport one turbine. A medium-sized power plant of around 1 MW rises to a height of around 40 to 70 meters depending on the nature of the terrain and wind flow, with the average length of wind turbine blades currently around 35 meters.
At this length, the blades are still transported by truck, but things are evolving towards larger and taller wind generators, with blades approaching 50 meters in length. Turbines intended for installation on solid ground that is, the blades of newly established offshore power plants are already commonly 90 or even 100 meters long.
At the Danish test center in Osterild, for example, currently the largest and most powerful wind turbine of its kind in Europe is being commissioned. One of its blades measures 115 meters, which exceeds the maximum permissible length of a football field by five meters. The area covered by the rotor is 43,500 m2 and the plant has an output of 14 MWp, more than ten times that of conventional wind turbines.
How to raise a giant
Wind turbines are simply growing higher and higher into the sky, and their installation requires increasingly sophisticated procedures and technologies. Spanish company AIRPES specializes in challenges of this kind, and its SGRE series hydraulic clamps firmly grip any blade weighing up to 45 tons so that the crane can lift it to the required height. Diagnostics or software updates to the clamp can be carried out remotely thanks to an integrated modem, so it can lift blades in a remote location in the mountains, for example, while still being in contact with the manufacturer's team in Spain.
However, the whole system depends on an uninterrupted supply of electricity - the consequences of a forty-ton blade breaking off at a height of one hundred meters are certainly not hard to imagine. A key element of the tool is therefore a back-up battery made up of GAZ cells, which supply electrical power to all the electronics of the lifting equipment, especially the hydraulic system controls. And in the event of a failure of the diesel generator that powers the hydraulics, the battery pack also serves as a backup power source.
The backup battery is stored in a specially designed box directly inside the clamp and is therefore lifted up with the clamp and blade during installation. The box is thermally insulated, as the turbine blades can be installed even in very remote and very cold areas. For the most extreme conditions, GAZ can also custom-manufacture batteries for AIRPES that can withstand temperatures as low as -40°C for long periods of time, i.e. 20°C lower than standard operating conditions.
The electrochemistry of nickel-cadmium batteries makes them ideal for UPS applications, as does their reliability and low maintenance. And since wind turbines are also built in remote conditions or at high altitudes, the wide tolerance of Ni-Cd cells to extreme temperatures also comes in handy.
The combination of wind generation and battery storage is otherwise not unusual. Wind farms, and perhaps to a greater extent photovoltaic plants, use batteries to smooth the generation curve in order to keep the supply to the grid as stable as possible even when there is little or too much sun or wind. You can learn more about this use of battery storage in the articles listed in the top right corner of this page.
For more information about technologies related to wind turbine construction please visit the website of Airpes whom we thank for their cooperation on this article.
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