SPP's two trading hubs on one axis: settled real-time against the day-ahead clearing price, in the market where wind sets the tone more than anywhere else in the country.
How do SPP day-ahead and real-time prices compare?
SPP hub prices peaks at $196 on Sun, 7 PM, against a low of $-41.12 — a swing of $237 across the window. North Hub is the heaviest area at 53 $/MWh.
Every line above, and who produced it.
Observed or settled values for the plotted intervals. Source: SPP.
Observed or settled values for the plotted intervals. Source: SPP.
Each hub’s settled real-time price, cleared day-ahead price, and any model forecast published for the same delivery hours.
Each day of the window on its own.
Every hour of the window, shaded by load.
| 0 | 6 | 12 | 18 | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sun, 10/11 |
| Hub | Peak ($/MWh) | Peak hour | Low ($/MWh) | Average ($/MWh) |
|---|---|---|---|---|
| North Hub | 53 | Mon, 12 AM | -31 | 11 |
| South Hub | 196 | Sun, 7 PM | -41 | -21 |
| Forecast | Avg miss ($/MWh) | Avg miss % | Bias | Hours |
|---|---|---|---|---|
| Day-ahead auction | $16.77 | 123.3% | +$11.58 | 48 |
The latest published vintage of each forecast, against what settled. Smaller is better on every column. Bias is signed: positive means the forecast ran high.
| Series | Produced by | Method | Horizon | Issued |
|---|---|---|---|---|
| Day-ahead clearing prices | SPP | SPP day-ahead hourly and real-time five-minute LMPs at the trading hubs; cleared market result | Day-ahead clears once daily; real-time settles every five minutes | Clearing time not exposed by this feed |
SPP publishes cleared prices, not probabilistic forecasts, so no band is shown. The day-ahead-to-real-time spread can reflect load and renewable forecast errors, outages, congestion, interchange, fuel costs, bids, and other changing system conditions; this comparison does not assign cause.
SPP settles trade against two hubs: North (Kansas, Nebraska, the Dakotas) and South (Oklahoma and the Texas Panhandle). Both sit inside the US wind belt, and the spread between them is mostly a wind-and-transmission story — when the north is windy and the lines south are full, the hubs price apart.
Wind output and wind-forecast error can affect commitment and congestion in SPP, alongside load, outages, transmission limits, bids, and interchange. This page measures the day-ahead-to-real-time price spread; it does not assign that spread to one driver.
SPP's day-ahead market is a financially binding auction clearing before delivery. Its prices are cleared market results rather than SPP forecasts. The scorecard measures their difference from settled real-time prices over matched hub-hours.
curl "https://askthegrid.com/api/v1/grid/series?iso=SPP&metric=dam&node=SPPNORTH_HUB"
Connect your agent to mcp.askthegrid.com and this forecast is a tool call away — the same host Claude and ChatGPT connectors already use.
Two aggregated price points: SPP North Hub across Kansas, Nebraska, and the Dakotas, and SPP South Hub across Oklahoma and the Texas Panhandle. They are the reference prices for trade across the fourteen-state footprint.
Wind. When overnight wind output exceeds what load and export capacity can absorb, prices clear below zero — wind with production tax credits keeps running at negative prices. It is among the most frequent negative-price markets in the country.
Mostly because the wind forecast misses. Day-ahead clears on the forecast; real time clears on delivery. A windier-than-forecast night undercuts day-ahead, a calmer one overshoots it — the scorecard above puts numbers on how often each happens.
Plotted window Oct 11, 4:00 AM CDT → Oct 12, 3:55 AM CDT. Real-time updates continuously; day-ahead once per day.
| Mon, 10/12 |
|---|
Darkest cells are the tightest hours. The window peaks at 196 $/MWh on Sun, 7 PM, local to the market.