Join the Exchange

Basis Risk: Nodal vs. Hub vs. Zonal

Understanding congestion risk across U.S. power markets

Power MarketsBasis RiskLocational PricingElectronX Education Series · September 2026

Anyone who buys or sells electricity in a wholesale power market quickly learns that there is no single price for power. The price depends on where on the grid the power is delivered. Two plants a few miles apart can settle at prices that diverge by thousands of dollars per megawatt-hour on a congested afternoon. The gap between the price at one location and the price at another is known as basis, and the uncertainty in that gap is basis risk.

Basis risk is one of the most important and least understood exposures in power trading. A hedge can be perfectly sized in volume and still lose money if it is settled at the wrong location. This paper explains where basis comes from, how the three main pricing constructs, nodes, hubs, and zones, differ from one another, and how those constructs are applied across the major U.S. regional markets.

Where basis comes from: locational pricing

Most organized U.S. power markets are run by an RTO or ISO (regional transmission organization or independent system operator) (FERC n.d.). These operators use locational marginal pricing, or LMP. The idea is simple: the price of power at any point on the grid is the cost of delivering one more megawatt to that exact point at that exact moment (ISO New England n.d.a).

An LMP breaks into three parts:

  • Energy. A single system-wide reference cost of generation. This component is the same everywhere in the market. This is sometimes called "system lambda".
  • Congestion. The cost of binding transmission constraints. When a line or interface reaches its limit, that constraint carries a shadow price, the marginal value of relaxing the limit by one megawatt, and each location's congestion component is the sum of those shadow prices weighted by how strongly delivery to that point loads each constraint. This is what makes prices differ from place to place.
  • Losses. The cost of electricity lost as electricity physically moves across transmission lines.

The energy component cancels out when you compare two locations, so basis is driven almost entirely by the congestion component, with a smaller contribution from losses. When the grid is unconstrained, prices across a region converge and basis is small. When a line, transformer, or interface hits its limit, prices on the two sides separate, sometimes dramatically, and basis widens. Congestion is the engine of basis risk (ISO New England n.d.a).

Nodes, hubs, and zones

RTOs calculate an LMP at every pricing point on their network. To make those thousands of prices usable, they are aggregated in two directions: up into hubs for trading, and up into zones for settling load. Understanding the difference is the key to managing basis (ISO New England n.d.c).

ConceptWhat it isWhy it matters for basis
NodeThe price at a single physical point on the grid (a generator bus or a specific delivery point), reflecting energy, congestion, and losses at that exact location.The most precise price, and the most volatile. A position settled at one node carries the full, unsmoothed congestion of that spot.
HubA defined basket of nodes averaged into one reference price. Hubs are chosen to be liquid, stable, and representative of a broad region.The market's benchmark for trading and hedging. Deep liquidity, but it does not reflect the congestion at any single node.
ZoneAn aggregation of nodes used to settle load in a utility or geographic area, typically a load-weighted average of the nodes inside it.Where most retail and load obligations settle. Basis appears between a zone and the hub, and between individual nodes and their zone.

Nodes

A node, sometimes called a pnode or a bus, is the price at a single physical point on the grid. Generators are typically settled at their own node, so a plant is paid exactly the LMP where it injects power. Nodal prices are the most accurate reflection of local conditions, and for that reason they are also the most volatile. A transmission constraint that binds right next to a node can send its price far above or even below neighboring points. A generator that has sold its output at a hub price, but is paid its own nodal price, is exposed to the basis between the two.

Hubs

A hub is not a place so much as a construct. It is a defined set of nodes whose prices are averaged into a single reference number. Hubs are deliberately built to be liquid and stable: they pull together many nodes so that no single constraint dominates the price, which makes them ideal points for forward trading, benchmarking, and financial settlement. Most exchange-traded and over-the-counter power products settle against a hub. The tradeoff is that a hub, by design, smooths away local congestion. A hedge placed at a hub protects against broad regional price movements but not against the basis between that hub and the specific node or zone where the physical exposure actually sits.

Zones

A zone is an aggregation of nodes used to settle load. Utilities and retail suppliers usually serve customers across many nodes, so the market defines a zonal price, most often a load-weighted average of the nodes in that area, as the settlement point for demand. Zones sit between nodes and hubs in both granularity and volatility. They capture the congestion that affects a load pocket as a whole while averaging out the noise of any individual node. For a retailer, the relevant basis is usually the spread between the zone where its customers sit and the hub where it bought its hedge.

The same constructs, applied differently

Every RTO uses nodes, hubs, and zones, but they define and emphasize them differently. The liquid hub in one market may be a single dominant benchmark, while another market spreads liquidity across several regional hubs. Some markets are strongly zonal in how load is settled and discussed; others push almost everything down to the nodal level. The table below summarizes the landscape.

MarketNotable hub(s)How nodes, hubs, and zones are used
PJMWestern Hub (the market benchmark), AEP-Dayton Hub, N Illinois Hub, Eastern Hub, Dominion Hub and othersThousands of pricing nodes. Load settles at utility zones. Western Hub is the reference for most financial trading. Congestion is hedged with FTRs, funded through ARRs.
MISOIndiana, Michigan, Minnesota, Arkansas, Louisiana, and Texas hubsNodal generation across a very large footprint. Load resource zones settle demand. Basis between north and south can be large when the regional interfaces bind.
ERCOTHouston, North, South, Panhandle, and West hubs, plus bus-average hubsFully nodal since 2010. Generators settle at resource nodes, load settles at eight load zones, and hubs are simple averages of a set of buses. Congestion is hedged with CRRs.
CAISONP15, SP15, and ZP26Nodal prices with load aggregated into default load aggregation points. The three trading hubs anchor the forward market. Congestion is hedged with CRRs.
NYISOZone G to J references; Zone J is New York CityEleven load zones with nodal generation underneath. Zonal structure makes the New York City and Long Island basis especially visible. Congestion is hedged with TCCs.
ISO-NEInternal hubNodal generation with eight load zones. Mass Hub is the liquid trading point for New England. Congestion is hedged with FTRs.
SPPNorth and South historically, West added recently with RTO expansion.Nodal Integrated Marketplace with hubs and load zones. Wind-driven congestion can move nodal prices sharply away from the hub. Congestion is hedged with TCRs.

Sources: CAISO n.d.; ERCOT 2024; ISO New England n.d.b, n.d.c; MISO n.d.; NYISO n.d.; PJM Interconnection n.d.; SPP n.d.

A practical reading of the table: in PJM, the Western Hub is the gravitational center of the market, and basis is usually framed as the spread from a zone or node back to that hub. In ERCOT, the four regional hubs and eight load zones do most of the work, and the north-to-south and Houston import constraints are the classic sources of basis. In NYISO, the zonal structure itself puts basis front and center, because the constraints into New York City and Long Island are so persistent that those zones trade at a structural premium.

Managing basis risk

Because basis is driven by congestion, the tools for managing it are the same instruments the RTOs created to let market participants hedge congestion directly. They go by different names in different markets but serve the same purpose:

  • Financial transmission rights (FTRs), congestion revenue rights (CRRs), transmission congestion contracts (TCCs), and transmission congestion rights (TCRs) are financial instruments that pay the holder the congestion difference between two locations. Buying the right path lets a participant lock in the basis between a node or zone and a hub (PJM Interconnection n.d.; ERCOT 2024; NYISO n.d.; SPP n.d.).
  • Hub trading concentrates liquidity at a benchmark so that the large, regional part of price risk can be hedged cheaply and transparently, leaving only the residual location basis to manage separately.
  • Basis products let participants trade the spread between a hub and a specific zone or node directly, rather than assembling it from two separate outright positions.

The practical discipline is to match the settlement location of a hedge to the settlement location of the underlying physical position wherever possible, and to treat any remaining mismatch as an explicit, measured basis exposure rather than an afterthought. A position that looks fully hedged in volume can still carry meaningful risk if it is long at a node and short at a hub. Sizing that residual, and deciding whether to carry it or hedge it, is the heart of basis risk management.

Key takeaways

  • There is no single price for power. Location determines price, and the difference between two locations is basis.
  • Congestion drives basis. The energy component of LMP is common to all locations; transmission constraints are what pull prices apart.
  • Nodes are precise, hubs are liquid, zones settle load. Each construct trades granularity for stability in a different way.
  • Every RTO uses all three, but differently. Knowing which hub is the benchmark and where the binding constraints sit is essential in each market.
  • Basis is hedgeable. Congestion rights and basis products let participants manage the spread between where they are exposed and where they trade.

References

Disclaimer

This material is provided by ElectronX for educational purposes only. It is a general overview of power market structure and does not constitute trading, investment, legal, or tax advice.