Is Renewable Energy All Divine?
Part 2.2
Hydropower does not last forever, although it does stand more than many lifetimes. According to George Kikiros who obtained a B.E. in Civil Engineering, at The University of Western Australia. All infrastructure is assigned a service life. Dams and many pipelines are assigned 100 years as an arbitrary figure, which is good, but not perfect.
What that means is that if all goes well some time approaching that time period, major upgrading will be necessary to strengthen gravity concrete walls, minor maintenance is always being done or should be, unless the ‘bean counters’ have taken over the running of the power generation company instead of Engineers.
Concrete dams after many years often need post-tensioning, where holes are drilled down through the concrete into the bedrock below the dam and a cable attached into the bedrock. And then tensioned literally ‘pulling’ the dam down onto its bedrock. The holes containing the cables are then filled with a ‘slurry’ concrete or chemical slurry which then dries/sets and maintains the tension in the cable. This action is required where it is determined that the dam is ‘sliding’ on its bedrock, in other words losing its friction on the bedrock from when it was constructed due often to water seeping through the bedrock, or is determined that because of instability on its bedrock and abutments it may be susceptible to overturning, which falling over. Other works may be necessary such as enlarging spillways if not a weir structure.
Other strengthening works may be necessary in tunnels/penstocks leading down to the turbines.
As far as power generation is concerned, all generators/ turbines wear out and eventually are replaced if it is determined that power generation is economically feasible after the cost of strengthening works on the dam, tunnels/penstocks and replacement of its turbines and so on, that’s if the dam gets good funding, if not, it turns to a big manmade waste impacting everything it’s in contact with.
However, these turbines do not last half of the dam lifetime, according to Renewables First, a UK company, they only get to turn and generate electricity for a maximum of 25 years, though they are some that are operating at a lifespan of 50 years still. After it’s life span it’s not really known what happens but, from the materials used, which is stainless steel, it alloys of turbine runners often become corroded or cavitated from being submerged in water. There are used to clean that up but without funding, they might run till no longer useful.
