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What future for wind turbines in Portugal?

20 April 2020

Article by José Carlos Matos, director of the Wind Energyarea at INEGI, and Filipa Magalhães, senior consultant. Originally published in the 41st edition of Renováveis ​​Magazine 

During the next decade, Portugal will have a large part of its wind assets reaching 20 years of age, a reality already present in some European countries, such as Germany, Spain and Denmark. What options are there after the 20 years of operation for which they were designed?

1) extend the life of these wind turbines for a few more years (taking care of safety-related issues) and, if necessary, replace some of their components?

2) replace them with others with more recent technology, possibly even with greater generating capacity?

3) or is the wind farm is deactivated entirely?

These are the options that any investor will consider. However, it is important to bear in mind that Portugal has made ambitious commitments , which are reflected in the National Energy-Climate Plan (PNEC) 2030, and it is urgent to define the rules of the game to achieve them, and its in this context that decisions will be made.

Before proceeding, it should be noted that the useful life of a wind turbine is usually defined as 20 years, in the face of very well-typified conditions. A specific wind turbine designed to support a given wind regime may have a useful life shorter or longer than the aforementioned 20 years (or 25 years, a value that some manufacturers have been adopting), if the wind regime to which it is effectively subject is more or less demanding than defined in the design conditions. That said, it is also important to note that although the wind turbine is from a normative point of view and for the purpose in question treated as a whole, it is composed of different components, whose durability are, not only strongly dependent on the loads to which theyre subject, but may be also subject to contractual specificities.

It is in this context that, with regard to the life span of wind turbines, despite still being a topic that raises many questions in the sector, the IEC - International Electrotechnical Commission created in 2018 a dedicated working group focused on the standardization of some practices that already exist in some European countries. The group of experts, which also has the participation of Portugal, foresees the publication of a technical specification (TS IEC 61400-28 - Through life management and life extension of wind power assets) in the next 2 years.

Even so, if the decision is to "prolong” the life of the wind turbines, there will inexorably come a time when they will have to be replaced or completely deactivated. And what to do next?

There is not yet a defined and aligned strategy in the sector in Portugal, with regard to the various impacts resulting from the deactivation of a wind turbine. At an European level, the sector has been attentive and has been working to define a sustainable life cycle for the various materials resulting from the end of life of this equipment.

Currently, the recycling rate of a wind turbine is between 85 and 90%, according to Wind Europe data , which includes the tower, parts of the foundation, and some components of the gearbox and the generator.

The sectors main challenge lies in the blades, namely in their collection, transport to the appropriate location and in the management of the final destination of the waste. These difficulties arise, on the one hand, from the proportions of the blades (today they reach dimensions of tens of meters in length) and, on the other hand, from the types of materials that comprise them (mostly fiberglass and resins).

To date, the sectors concern has been centered on the production of increasingly lighter and larger blades, with materials with lower recyclability rates being introduced into its production cycles. Although this is a worthwhile effort, it does not constitute a solution for the blades of wind turbines currently in operation whose most common destination has been landfill.

It should also be noted that the most recent use of concrete in the construction of the support towers of the machines will imply new challenges in the not too distant future - the installation of hybrid towers became more popular in Portugal from the end of first decade of the 21st century. It is, in any case, a challenge shared with countless sectors that use cement in their activity.

In the future, solutions will involve extending the life of the wind turbines to the maximum and changing the production processes of the blades, incorporating new materials with higher recycling rates and greater durability. Here too, the concept of circular economy, now very much in vogue, makes perfect sense. The exploration of secondary markets will be one of the alternatives for wind turbines that are still suitable for production, thus delaying their decommissioning.

It is, in any case, a mistake to think that this issue is to be dealt with in the distant future: one of the European Commissions major short-term priorities (2020-2022) with regard to innovation and research will be the recycling of blades and, in the medium term (2025-2027), the development of methodologies for recycling materials and components (ETIPWInd Roadmap).

Everyone should be called to this discussion that now arises in our country: "What is the future of wind turbines in Portugal?”. The time has come for the various stakeholders, direct and indirect, to discuss solutions and point out possible paths, in order to achieve economic, environmental and social sustainability. Perhaps so, Portugal will find a new participation in the value chain of this new economic paradigm.

Photo: Benjamin Rasmussen / Bloomberg Green
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