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Comment by qayxc | Hacker News Reader

Careful there buddy!

Take a look at the actual time when wind power contributed little or nothing. It's mostly night hours between 23:00 and 5:00.

Contrary to conventional power sources, wind power can be regulated basically "on-the-spot" by turning turbines on and off.

Living next to a small on-shore wind farm, I can tell you from first hand observation that most of the time turbines are turned off deliberately, because production simply exceeds demand.

A chart like the one you've linked to doesn't tell the whole story and can be very misleading indeed. You'd need to plot the actual load on the grid versus production to get a better picture.

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Why then, would they shut down a wind turbine rather than a gas turbine. There was no point in the last year where gas turbines were not supplying power.

If what you say is true, then the grid is being run in a more carbon intensive way than necessary. Why would this be?

My guess: When the spot price of electricity turns negative (or low enough that is not covering costs), a wind turbine can put on the brakes immediately, whereas a gas turbine might prefer to accept some loss.

Because, as qayxc intimated with "Contrary to conventional power sources", it is more expensive to turn gas turbines off and on again than it is wind turbines. Price will dictate action in a marketplace, so sufficient incentives need to be introduced to motivate greener supply.

This is correct. And the costs are built into the contract. Wind and hydro dams are very easy to control. Gas is quite easy to control. Coal costs more to start and stop, but nuclear nearly changes in output over the course of a week. Nuclear is tuned to output the base load, the level below which demand never drops. Then the other sources are layered on top.

For the situations where all power sources are at max output and there is still not enough power, then the UK will pull power from France. This typically happens when East Enders (TV Soap Opera) finished and millions of people turn on the kettle (high powered water heaters of 2 or 3 kW).

Because gas and other fossil fuels are inelastic - it's expensive to turn them off or on, and it can't be done rapidly. The fact that wind can be turned on or off at will means they can be used to balance demand spikes.

Some valid points.

I'm curious though. If the UK wants to 'go green', then why turn wind turbines off at all, rather than turn off some carbon-based power stations instead? What's the reasoning behind that?

This is a problem I've raised before - if we have excess wind electricity, why aren't we storing it? The UK doesn't really have that much pumped storage/hydro: you need hills and dams, and almost all of those are in areas of outstanding natural beauty, and are therefore difficult to build.

wouldnt the turbines be safer if they are spinning instead of being parked?

you could just disengage the dynamo..

No, that'd be a bad idea.

Keep in mind that the rotors and mechanical parts are subject to wear and tear.

A rotor that's feathered experiences less mechanical stress and thus lasts longer. Same goes for any other moving parts.

It's a measure to increase the lifetime and reduce the risk of fires (e.g. from spinning too fast due to lack of mechanical load from the generator).

I'm no expert, but I guess if you disengage the load the turbine blades would accelerate until the internal heat losses to friction matched the energy input from the wind. In other words, they'd spin very quickly, probably far in excess of their design speed, meaning at best that they would wear out much more quickly, or I guess more likely RUD (rapid unscheduled disassembly), causing them to be considerably more dangerous.

No. A parked turbine has its blades furled and is locked in place. A freely spinning but disengaged turbine is super dangerous because there is nothing to stop it from overspeeding and that can happen quite quickly with the right gust of wind. So you always want to have drag on a spinning turbine.

That's how you get this: https://www.youtube.com/watch?v=u14tBwO5QVQ

Ultimately, the energy has to go _somewhere_, if it's spinning.

This is why electric cars needs smart charging - plug it in when you get home, and expect for it to be charged by the time you need to go to work - but the actual charging hours should be linked to the grid in order to manage overall demand.

Its a shame that this regulation and UI environment is not already ready, since these vehicles are already being mass-manufactured.

Tesla supports this in some markets where they’ve partnered with the utility to orchestrate aggregate EV charge demand.

There were couple of days recently when almost zero energy was generated by wind: https://www.thetimes.co.uk/article/blackouts-fear-forces-pow... (an excerpt without being paywalled: https://www.thegwpf.com/britain-faces-green-energy-disaster-...)

The excerpt speaks for the "quality" of this kind of journalism: headline says

> "Britain faces green energy disaster as lack of wind triggers new blackout warning"

Actual quote says:

> National Grid said the margin notice “highlights that we would like a greater safety cushion between power demand and available supply” but “does not signal that blackouts are imminent”.

In short: yes, regenerative or "green" energy requires a different approach, including overprovisioning, short term storage, and stand-by power stations (e.g. natural gas-powered ones) in order to work reliably.

That's not news, however, that's a well known fact. Plus both wind and solar can be predicted fairly well over the short term and a more intelligent grid could be used to adjust demand accordingly to also help with this.

It's an issue, sure, but not a show-stopper.

> The excerpt speaks for the "quality" of this kind of journalism: headline says

I agree, just I couldn't find a better link to the National Grid announcement.

Posting a link from a 240-year-old Western medium that was downvoted to -3 from the default 1 was the last time I wasted my time on commenting a HN post.

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