10.  Reflections on repowering

The conventional lifespan of a wind turbine is around 20 years (cf. standard NF EN 61 400). Guaranteed-price electricity purchase contracts are usually for 15 years, after which the electricity is bought back at the market price. As wind power capacity continues to grow over the next few years, it will be necessary to replace wind turbines that have reached the end of their service life, in a process known as repowering.

Over a period of 15 to 20 years, wind turbine technology has advanced considerably. So-called "repowering" phases provide an opportunity to replace old wind turbines with new, more efficient ones. These operations offer a number of advantages:

• Whereas the commissioning of a new site requires a large number of studies to assess its potential, extending the life of an existing wind farm allows us to...