Basis risk
The risk that the price where you actually buy or sell power moves differently from the price where you hedged it.
Basis risk is the gap between the price you're exposed to and the price you hedged. A wind farm in West Texas gets paid at its own local node, but the liquid market where it can sell a hedge is a hub hundreds of miles away. If the two prices moved together perfectly, no problem — but they don't. The difference between them is called basis, and the danger that it moves against you is basis risk.
The classic failure mode: a generator locks in a fixed price at the hub, feeling fully hedged. Then a transmission line near the plant becomes congested, the local nodal price collapses, and the plant's actual revenue falls — while the hub price it hedged at barely moves. The hedge pays off exactly as designed and the project still loses money, because the hedge was written on the wrong location.
Basis risk is the tax that nodal markets levy on distance from liquidity, and managing it is a core discipline for anyone with a physical asset. The tools include buying congestion-hedging instruments, choosing hedge structures that settle closer to the asset, and — most fundamentally — understanding which transmission constraints sit between your node and your hub, since those constraints are the machinery that generates basis in the first place.
For the technical reader
Basis between node and hub is, mechanically, the difference in congestion (plus loss) components of their LMPs, so a basis position is an implicit position on the shadow prices and shift factors of the constraints separating the two points. Its distribution is ugly for hedgers: regime-dependent and heavily skewed, near zero for long stretches and then persistently large when a constraint binds — episodes driven by identifiable causes like transmission outages, new generation additions, and load growth.
Hedging instruments include CRRs/FTRs (auction-priced claims on congestion rent between two settlement points) and structuring choices such as hub-settled versus node-settled PPAs, which allocate the basis between offtaker and generator rather than eliminating it. Quantitatively, basis analysis is congestion analysis: forecast which constraints bind, with what shadow prices, and how your node's shift factors expose it to each.