Repowering wind farms with fewer wind turbines

In many countries, wind turbines that are close to the end of their expected useful life are beginning to abound. The tendency to extend its operation beyond that term is also growing.

In the case of Spain, the age of the state wind farms, with a total installed capacity of 20,000 MW, has already exceeded more than half of their useful life, established between 15 and 20 years, according to data from the Wind Business Association ( AEE). The association itself indicates that the trend in the sector is to extend the operation of current wind turbines beyond the expected 20 years. On the other hand, the adequate spaces in the territory for the installation of new wind farms are running out and the new ones are installed in areas where there is space, but where the wind conditions are not the most suitable.

For this reason, as explained by Ricard Horta, professor of Electrical Engineering at the Terrassa School of Industrial, Aerospace and Audiovisual Engineering (ESEIAAT) of the Polytechnic University of Catalonia – BarcelonaTech (UPC), “if you want to reach the goal of cover 35% of the energy demand with clean energy, it is very important to start repowering the wind farms in Spain and Catalonia, as is already being done in Germany and the Netherlands. It is the only way to renovate the park, increase production and minimize environmental impact. For this reason, very important investments are necessary on the part of the companies and changes in the bureaucratic circuit of the administration. At this time, the current legislation does not take into account the obsolescence of the turbines”, says Horta.

It is in this line that the ESEIAAT student Carlos Rosa has prepared his Final Degree Project. Rosa has created wind farm management software on the MATLAB platform that would help repower wind farms in any company in the sector, that is, a tool that would facilitate the dismantling and replacement of current, aged wind turbines with others of greater power. , with greater height and blades of superior dimensions.

Carlos Rosa affirms that “repowering means fewer wind turbines, with better technology and more powerful, and, therefore, more efficiency, more productivity and less costs, because the wind is better used, maintenance is reduced, the energy generated increases, fewer the hours of unemployment and there is less visual impact”.

Carlos Rosa. (Photo: UPC)

The tool that Carlos Rosa has created allows companies involved in the value chain of a wind farm to work with all the data necessary to carry out repowering with guarantees, such as data on the direction from which the wind is coming and its speed in a certain latitude and longitude, the number of generators in the park, the model and the heights of the wind turbines, the power curve, the cutting speed, the average temperature, the annual energy produced, the calculation of the energy produced by the new devices and the calculation of the distances between wind turbines.

The student has also investigated how to apply the new system created in a wind farm like the one in Les Colladetes (Perelló, Tarragona), where 54 45-meter-high turbines are currently installed. The current power of the park is 35,640 kW. His proposal is to dismantle it and replace the 54 turbines with only 14 wind turbines with a height of 100 meters, so if the nominal power remains around 35,000 kW, the park could increase energy production by 140% with 40 turbines. less. In fact, the old generators each produce 0.676 GWh per year, while the new ones would produce 6.26 GWh per year.

For Carlos Rosa, “the wind farms in Spain and Catalonia must start a repowering process sooner rather than later. According to the University of Queensland, in the world there are 2,000 wind farms installed on green spaces of ecological value. Repowering will help to greatly minimize environmental impact and produce more clean energy. In this sense, the system that I have created can facilitate the execution of repowering projects. However, bureaucratic procedures must be streamlined by the administration, and important investments must be made by companies”, concludes Rosa. (Source: UPC)