Summary: US renewable developers securing long-term PPAs assume the contracted price floor provides comprehensive hedging against spot market volatility. In reality, PPA settlement happens at a specific demand node (often far from the injection point), creating unhedged basis risk. A merchant solar plant injecting at a supply-rich node (where spot prices are $25-35/MWh) under a PPA settled at a premium demand node ($55-65/MWh) experiences a persistent $30/MWh spread. The plant must buy low at injection and sell high at settlement, but financially settles at the higher price. This creates a hidden revenue leak. A 200MW project modeled at 8.5% IRR assuming $50/MWh commodity price realizes 5.2% when systematic basis risk bleeds $6M annually from marginal cash flow.
PPA Nodal Mismatch Creates Hidden Commodity Leakage
US renewable developers view PPAs as comprehensive hedges. A $50/MWh PPA floor is modeled as a hard revenue minimum protecting the project from merchant spot market volatility.
This assumption collapses when PPA settlement nodes diverge from generator injection nodes. In many US markets, renewable projects inject at supply-rich peripheral locations where spot prices are suppressed. However, offtakers demand settlement at demand-center nodes where prices are premium. The PPA strike price ($50/MWh) is fixed at the demand node, but the plant's marginal revenue comes from the injection node. The gap is basis risk.
Consider a 200MW merchant solar project in ERCOT's South Hub, injecting at a peripheral node (South Houston). Spot prices at injection average $28/MWh. The project has a $50/MWh PPA settled at the Houston demand node, where spot prices average $58/MWh. The plant sells power at the injection node for $28 but must purchase it at the demand node for $58 to fulfill the PPA settlement at $50. The developer loses $8/MWh, or $6M annually on 750MWh.
The financial damage is structural and persistent. An 8760-hour model assuming flat $50/MWh pricing projects 8.5% IRR. In reality, basis risk creates a $6M annual leakage that is not offset by the PPA floor. The realized IRR collapses to 5.2%, dropping below lender hurdle rates and triggering equity erosion over time.
Current prefeasibility models treat PPAs as universal hedges without nodal specificity. They fail to model the exact settlement nodes and calculate resulting basis risk exposure. They assume a PPA price floor holds uniformly across all market conditions.
Developers must immediately move to physically-settled PPAs or financial transmission rights (FTRs) that explicitly hedge nodal deltas. Alternatively, projects must demand that PPAs include explicit basis risk allocation language, with offtakers sharing the cost of premium demand node settlement.
Bottom line: A PPA is only a hedge if the settlement node matches the injection reality. Without nodal matching, the PPA is a revenue cap, not a revenue floor.
Modeling nodal basis risk in US PPA markets requires mapping exact settlement nodes, simulating historical spread distributions, and calculating the financial impact of persistent basis gaps. Static PPA assumptions cannot capture the commodity leakage that transforms a nominal hedge into a margin erosion mechanism. Accurately sizing this risk requires preFeasibility environments that dynamically model nodal spreads against real-time LMP data.