Daily guide · SE1 · 2026-07-31
The number your Sweden Luleå price model has to beat this week
All numbers computed from the week's published auction results at publication and frozen — this article is an honest snapshot, not a page that rewrites itself. Reproduce via the API.
The benchmark to beat in Luleå this week is a persistence MAE of 8,77 EUR/MWh across the six days. That average hides a wide spread. The weekend of 25 and 26 July is quiet, with persistence errors of 6,93 and 5,15 EUR/MWh against day means of 6,2 and 3,4 EUR/MWh. The middle of the week is where the work is: 27 July carries a persistence MAE of 14,43 EUR/MWh on a day mean of 17,82, and 28 July sits at 11,40 EUR/MWh.
The pattern to note is the mismatch between error and level. On 30 July, persistence MAE is only 5,03 EUR/MWh while the day mean is 12,56 — a firm day the naive model tracks well. The hardest days combine higher means with sharper moves, so beating 8,77 depends almost entirely on the 27 and 28 July block.
One caveat for the reader: our own last-59-day scorecard shows an MAE of 9,12 EUR/MWh against a baseline of 8,11, so we are currently behind persistence. Focus modelling effort on the mid-week peaks rather than the calm weekend edges.
Before you train anything on SE1 prices, you need the number your model has to beat. In day-ahead forecasting that number is naive persistence: predict that tomorrow's curve equals today's. It costs nothing, needs no features, and it is embarrassingly hard to beat — because power prices are dominated by daily and weekly rhythms that persistence gets for free. We computed it on this exact week:
8.77 €/MWh
persistence MAE on this week's SE1 auctions — the bar. A model that can't get under this adds negative value.
9.12 vs 8.11
our live production model vs its persistence baseline, trailing 59 scored days — the same scoring, in public, on /accuracy
Why the bar moves: this week, day by day
| Target day | Day mean €/MWh | Persistence MAE |
|---|---|---|
| 2026-07-25 | 6.2 | 6.93 |
| 2026-07-26 | 3.4 | 5.15 |
| 2026-07-27 | 17.82 | 14.43 |
| 2026-07-28 | 7.22 | 11.4 |
| 2026-07-29 | 15.56 | 9.66 |
| 2026-07-30 | 12.56 | 5.03 |
Calm days make persistence look unbeatable; transition days (weather swings, weekend boundaries) are where a real model earns its keep. Averages hide this — always look at the daily distribution.
The part everyone gets wrong: the features
The model is the easy half. The silent killer is lookahead: training on weather reanalysis instead of the forecast that existed at issue time, on revised load data, on same-day flow averages that hadn't finished flowing at the auction. Backtests built that way look brilliant and die in production. Our Quant feature matrices serve one row per (issue day, 15-minute slot) where every column is documented with when it became knowable — the same rows our own models train on:
curl -H "Authorization: Bearer YOUR_KEY" \
"https://voltcast.com/api/v1/features/SE1?issue_from=2026-07-01&horizons=1"
# columns include: price lags · previous-run weather (as forecast AT issue)
# · grid drivers (lagged to last COMPLETE day) · day-ahead load/RES forecasts
# · ensemble spread · target_price label (null until matured, never imputed)
Start free: the persistence bar above needs nothing but GET /v1/prices/SE1
(free tier covers any one zone). When your walk-forward backtest beats it honestly, prove it in public on the
Forecast Bench — forward-blind, open scoring code, and our
own model is auto-entered under identical rules. If you'd rather buy the plumbing than build it, that's
the Quant tier.
Method & citation. Prices are hourly means of published day-ahead auction results (native 15-minute periods averaged; ENTSO-E/SMARD, attributed). Wholesale-price component only — grid fees and taxes come on top and vary by supplier. Cite as "Voltcast Research, voltcast.com/guides/quant-features-se1-2026-07-31".
The monthly European power roundup
Negative-price records, the biggest spreads, which zones were hardest to forecast — every number computed from our production data, on the 2nd of each month. No filler, unsubscribe anytime.