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Comment by tgb | Hacker News Reader

Why was applying a brake so energy intensive? Seems like it'd be practically free.

In general, turbines use energy to start up! They need to do this in order to overcome the very large inertia. Imagine a wind that lasts for 4 hours, but to harness that, you need to be spinning up for 1 hour, leaving you only 3 hours or useful energy. Instead, they spin up the blades to the optimum speed and can get payback for that initial spent energy.

Also, you still need energy to run the computer that monitors everything.

https://oilprice.com/Alternative-Energy/Wind-Power/How-Much-...

After braking the turbine isn't generating the energy it needs to in order to be net positive.

How bad would it be to insert a comment about regenerative braking here?

But yeah, that sounds so bizarre. The Emperor's New clothes territory.

Regenerative braking is not an issue here. Wind turbines slow down the wind to generate electricity, so, in a sense, they are always doing regenerative braking when operating as intended. They would only be mechanically braked when this (and also blade feathering) is insufficient or inapplicable for some reason.

For this to lead to a net negative, it has to be more than just a lost opportunity to make energy: either it is a significant energy consumer (i.e. not just a dissipater), or the turbines must be incapable of producing significant amounts of energy even when working correctly. There is something that has not been explained here.

That the turbines were incapable of producing significant amounts of energy even when working correctly, is not out of the really of reason.

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