Why do windmills have a lifespan instead of being repairable/upgradeable?
In: Engineering
It costs too much.
Sure you can replace the rotor on a worn out wind turbine and that goes for both the wing and generator parts. You can put a cost estimate down for the work hours of the engineer and the part that probably hasn’t been produced in five years.
You can also buy newer more modern parts and simply build a new turbine that makes five times the money per dollar invested.
What choice would you make?
Everything man made has an economic lifetime, after which the costs of maintaining or upgrading are higher than building new ones. Ships are a good example of this, many go to the scrap yard after 20 to 25 years, but with good maintenance, they could serve for 40, it’s just to costly to do this though, newer ships are more efficient and economic in use. Same with Trucks, machinery, etc.
Same with wind turbines. Newer turbines are FAR more efficient than old ones, turbine technology has advanced a lot in 20 years.
Denmark for instance had recently replaced old turbines after 20 years instead of the planned 30, because it’s cheaper and more economical.
And since the power infrastructure and the foundations were already in place, the cost of replacing them isn’t all that high.
Many are upgradeable — it is called “repowering” the turbine. It is the blades that tend to have a firm lifespan (20-30 years), because they are fibers (glass or carbon) suspended in a resin matrix. Over decades of loading and unloading, that material has degraded and can no longer sustain the loads. So the blade is scrapped and landfilled. New research is being done that will allow blades to be recycled, but to keep running past 20-30 years, the turbine would need new blades.
Keep in mind that there is NO engineered material that doesn’t eventually break down due to fatigue. The design goal is to have them last as long as it makes sense financially—to expand the material beyond 30years would require such groundbreaking material work that the cost would be infeasible, so no one does it. As one of my professors used to say — any one can build a bridge that doesn’t fall down; it takes an engineer to build a bridge that barely doesn’t fall down. Our goal is to meet the demands of the project without vastly over engineering the thing.
Also keep in mind that while we recently have focused on wind turbines and solar panel lifespans traditional power plants also require major maintenance/overhauls and without that would not last the 20-30 years of a wind turbine or solar panel. Basically everything requires maintenance and overhauls and singling out wind turbines or solar panels or batteries is just ignoring the reality of every other source of power on this planet
You could think of them like computers and cars. They are built to be serviceable and repairable. At a certain point though, it costs more to fix them than replace them. If they’re designed right, they live their lives with minimal repair costs and pay for themselves. Once they’ve reached the end of life, they are retired and replaced.
Fortunately all the infrastructure is in place already, so replacement is quicker than original install.
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