Revert Amber tariff to fetch every minute

[ross-w]

It looks like the Amber tariff was changed to fetch every hour as part of #17601

To me this seems like a simple copy/paste error. This PR reverts to the previous behaviour. If there is an issue with fetching every minute, please let me know.

Amber's pricing will change extremely frequently, and fetching it every hour is not sufficient to get an accurate view of pricing.

Additionally, Amber will be switching to 5-minute settlement (down from the current 30-minute) early this year, which makes the fetch frequency even more important.

[andig]

It looks like the Amber tariff was changed to fetch every hour as part of #17601

@ross-w right, sorry for the regression. That was intentional since the actual nature of the tariff was not clear to me.

evcc currently works with hour-slots only. Are you saying that Amber changes the prices for the hour-slots every minute? I'm wondering how valid our planning algorithm is for that case. Or does Amber actually return quarter-hour or even minute slots? I believe that evcc wouldn't even handle those atm.

[ross-w]

Hi @andig it's a long story but presently Amber returns simulated 30-minute slots, based on estimated values of the 5-minute spot price. From some time soon, they will return 5-minute slots instead (for most customers; some will remain on 30-minute slots for technical reasons.) The current slot is often the actual price, but everything in the future is an estimate (including within the hour) and can (and likely will) change.

Presently evcc seems to take an average of the two returned 30-minute slots for the hour slot price (I think?). This works to some degree. Obviously some times of day will be better than others, and this is "good enough" for planning purposes.

To answer your question, yes. From evcc's point of view the "hour" slot price will change every minute. Hopefully not by large amounts, but it can happen.

It would be nice if evcc's planning could handle this, but I imagine that's not an easy thing to design :) In the mean time, at least having the most up-to-date data would be an improvement.

[andig]

It would be nice if evcc's planning could handle this, but I imagine that's not an easy thing to design

I guess we'll move to 15m slots from planning perspective, but nobody's working on that right now. Tbo, I'm happy that planning works quite well as it currently is :)