this post was submitted on 21 Oct 2023
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Futurology
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Yeah the rotating mass of a single turbine is relatively small but inertia is significant due to the size of the rotor (rotor diameters of 100 to 200 metres are not uncommon). On top of that we should compare the inertia of a entire windfarm to a convential turbine.
The size difference is still huge. A new onshore turbine might be 5MW, offshore is now maybe 10-15MW, but a single big turbine in say a nuclear or coal plant could be hundreds of MW or even into the GW. The machines are just much bigger and much more massive.
That doesn't mean we should prioritise them, however. The UK's National Grid did a Future Energy Scenarios study and determined that the fastest way to net zero is to go hard on current renewable technology. It's ready, it's proven, and it's cheap and quick to build. Money spent on nuclear is just money that could be spent on getting renewables up and running more quickly, and we'll almost certainly use more combustible fuel waiting for nuclear than we would backing up renewables. If we build a large excess in renewable capacity we should be able to meet almost all demand, regardless of when the sun isn't shining or the wind isn't blowing (the sun still shines through the clouds and it's usually always blowing somewhere), and if we focus on building nuclear afterwards then by the time that's operational our demand may have increased so much that the excess of renewables isn't an excess anymore.
In terms of grid stability, rotating stabilisers are one solution. They're basically giant, heavy spinning discs, providing the same mass and inertia you would get from a large turbine, but driven electrically off the grid. They're used often on large ships, eg cruise ships and aircraft carriers, however on land there is a little concern over what might happen if they fail - the last thing you want is several hundred tons of metal spinning at hundreds or thousands of RPM rolling through the countryside lol. It's quite funny how the manufacturers have different ideas on how to deal with this, GE use gearing to reduce the RPM, Siemens use loads of sensors and monitoring to detect when it's failing before it happens, and ABB plan on shunting all the momentum into this smaller thing housed in a brick building that they hope will contain it.