Hacker News Reader

Comment by ajross | Hacker News Reader

You didn't provide a cite, FWIW. But taking the numbers as given:

Those aren't the right metrics. First, capacity factor is an approximation of "fraction of maximum", not reliability at all, which is a whole-grid measurement.

Find the data for any one gas plant. How often was it producing (emphasis in the original) no power? I'll bet anything that most plants are offline quite a bit more than 10%, precisely because demand itself is variable and gas is the easiest plant to bring up and down. Yet you call one a "reliability" metric and the other not, why?

In fact as a whole, German wind power has been exceedingly reliable. Wind power everywhere has been exceedingly reliable. The world as a whole has been building out wind like crazy over the last decade (because it's cheap and great) and... I'm not aware of even one instance of a "calm day blackout". Not one. Have a cite for that?

View on HN

I'll take the other side of that bet.

Fossil and nuclear plants routinely run at 90% of nameplate capacity. If a gas plant is down more often than that, it's because that plant is a peaker, which exists to make up for things like, say, the wind dying down.

I'm sure there's a somewhat tedious discussion to be had about how France's recent adventures with their decaying nuke plants affect that 90%. Have at it if this interests you.

So you are comparing "any one gas plant", the output of which can be fully controlled, with "whole-grid measurement" for wind? As a whole grid, wind generation capacity is mostly dependent on wind, and not on demand. While gas is used usually for those cases where such power as wind does not cut it. I dont see how you can compare the two. A gasplant CAN produce 100% output if we wish, wind cannot. You can of course compensate somewhat by building out several times the capacity you need in extremely disperse geographic locations (>1000 miles distance between each farm). Could be done, but not sure how its gonna impact the climate change (those farms need to be built and require continuous maintenance).

Uk has wind capacity factor "long-term average of around 27%". https://www.eci.ox.ac.uk/publications/downloads/sinden06-win...

The reason is that wind generation is optimal during a certain wind speed, and less or no power is generated if winds are too slow or too fast. And wind power blackout occurs not only during calm days, but also during very stormy days. In total there is plenty of occurrences when a specific area has no wind at all. The correlation in weather can be seen in wind farms as far as 800 miles apart. https://www.eci.ox.ac.uk/publications/downloads/sinden06-win...

2021 was a year of very low wind speeds across whole northern europe. https://climate.copernicus.eu/esotc/2021/low-winds

Additionally, wind power may be going down in strength... due to climate change https://www.ft.com/content/d53b5843-dbe0-4724-8adf-75c66127e...

> So you are comparing "any one gas plant", the output of which can be fully controlled, with "whole-grid measurement" for wind?

That was absolutely what I was not doing. That was a counterfactual presented to refute the grandparent, who was.

The source I linked has data for a few other countries, and crucially has "whole-grid" wind measurements for the UK. And the UK never went to 0 for a whole 30 minute reporting period! 99th percentile was under 2% of rated output, though.

> You didn't provide a cite, FWIW. But taking the numbers as given:

Ah, hell. It was meant to be 'https://energynumbers.info/germanys-offshore-wind-capacity-f...', which was Google's infobox for when I searched 'germany wind power capacity factor'.

> Find the data for any one gas plant. How often was it producing (emphasis in the original) no power? I'll bet anything that most plants are offline quite a bit more than 10%, precisely because demand itself is variable and gas is the easiest plant to bring up and down. Yet you call one a "reliability" metric and the other not, why?

I call wind's lack of production a reliability metric because I don't get to choose when the lack of production happens. My home's generator might only run for <1% of the year, but as long as it runs when I need it it's perfectly reliable.

> I'm not aware of even one instance of a "calm day blackout". Not one. Have a cite for that?

What's a 'calm day blackout'? Is it when there's no power produced by an individual wind farm, or is it when rolling blackouts happen because the wind farm didn't produce enough power, in conjunction with the rest of the power system?

The former is pretty common as shown in the link, and you could arguably say that Texas's winter blackouts from a few years back were an example of the latter. (lots and lots of both demand and generation issues in that scenario, but wind didn't come out covered in roses either, and while wind wasn't expected to produce much power in the winter there to begin with 'we don't expect this source to produce much power in the winter' is not a fantastic argument in favor of it being reliable)

Reply on news.ycombinator.com