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Fastfaxr t1_jax3ewd wrote

Never use polynomial fitting if you dont need to.

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VikThorior t1_jazm9f9 wrote

When you fit data, you must have a model in mind. You don't just take something that seems to fit well. Otherwise, a 547th degree polynomial will do the job, but it's really not useful.

Here, your fit seems to suggest that, when the wind is strong, fossil fuel usage increases again. What is the model, the hypothesis, which would explain that?

Also, have you checked if every coefficient of the model is statistically significant? I'd guess that the 3rd isn't.

My guess for the best fit would be something resembling a logistic function: when the wind tends to infinity, fossil fuels tend to 0. In your model, fossil fuels would tend to infinity, which is... unlikely.

If you don't want to come up with a model, you have solutions: a moving average or a local regression like LOESS, which has the advantage to give a confidence interval.

Conclusion: regressions need to mean something. They must not be chosen without a model, even just hypothetical, in mind.

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sault18 t1_jawt6p6 wrote

It looks like there might be a hard floor of 9GW fossil generation that is more apparent at higher wind speeds. Either turning the fossil plants completely off is not allowed by contract or law maybe? Or this grid needs the inertia of these fossil power plants? So, the apparent upswing in the curve fit at very high windspeeds is a bit misleading. Also, extremely high winds might be associated with cold fronts / snaps that cause wind farms to feather their turbine blades or electricity demand to spike.

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Barra79 OP t1_jax6k0u wrote

Wind turbines turn their blades to a full stall position in high wind conditions to prevent damage to the turbine. So if the turbines are not producing electricity at high wind speeds, then more electricity has to be produced using fossil fuels. The wind drought in Germany before Christmas coincided with the coldest weather conditions there this winter.

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Barra79 OP t1_jawiu34 wrote

Electricity Power Source: https://www.entsoe.eu/ ENTSOE API.
Wind Speed Source: https://open-meteo.com/ Open-meteo API, taking the wind speed in Hamburg Germany at a height of 80m.

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kompootor t1_jax8tav wrote

Possible/probable (almost certain? unless you corrected for it) confounding: as wind speed will correlate (causatively, but the wind isn't just local) to temperature gradients, you will find correlation to time of year and time of day, both of which correlate highly to light and temperature which correlate to power demand.

Also, as I always note: you should include credit to yourself, date of graph creation, and cited data sources, in text on the image itself, since jerks like to copy reddit images everywhere without backlinking.

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LargeMarsupial89 t1_jax7d2w wrote

What is a possible conclusion from this relationship?

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Barra79 OP t1_jaxahk1 wrote

That despite the German governments claim that they have a 63 GW total wind capacity, they are still burning large amounts of fossil fuels when it is not windy.

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sisiredd t1_jazgb7d wrote

So they say that when the wind blows, they can generate up to 63 GW from wind power (that's what capacity means). What's wrong with that? Of course they have to rely on other energy sources when there's no wind.

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Swimming-Ebb-4231 t1_jaxa8ws wrote

Dude did you steal this post? Why mark it OC?

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Barra79 OP t1_jaxbmq1 wrote

No, its mine!

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Swimming-Ebb-4231 t1_jaxcm92 wrote

Well it was posted three hours ago by a user that deleted both the post and the account and I can prove it

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Barra79 OP t1_jaxemks wrote

No you cant, because I posted them with my account which isnt deleted. I deleted the posts because I got a lot of negative feedback about the fact that I had power on the x axis. I fixed the graphs but had to create new posts as you cant edit your post.

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