SPP (Southwest Power Pool)

SPP is known as wind country, and its queue is wind-dominated. But on the same deliverable test, signed interconnection agreement, in service by 2028, SPP holds about 2.0 GW of firm gas, the second most of any US market after ERCOT and well ahead of PJM and MISO. It is a small number in absolute terms and an interesting one relative to the market's low profile.

The deliverable gas is concentrated in Oklahoma and the Texas Panhandle, with smaller positions in Nebraska and Colorado. SPP is largely a market of vertically integrated utilities, so like MISO the firm build leans on the utility rather than a deep merchant field, but the queue here does carry a cleaner signal than MISO's because SPP marks executed agreements explicitly.

For a data center willing to look past the marquee markets, the Plains pair cheap land and existing gas with a firm-power picture that is thin but not empty. It is a secondary option, not a headline one.