Fixed, Index, or Blended: Choosing a Contract That Fits

When you go to market for energy supply, you'll encounter three main contract structures: fixed-price, index (floating), and blended. Each one shifts market risk between you and your supplier differently. Understanding how they work — and when each makes sense — is the single most important thing a commercial buyer can know before signing a contract.

Fixed-Price Contracts: Certainty Has a Cost

A fixed-price contract sets your energy supply rate for the entire contract term — 12, 24, or 36 months is most common. You pay the same rate per kWh (or per MMBtu for gas) regardless of what happens in the wholesale market. If prices spike, you're protected. If prices fall, you don't benefit.

Where the risk premium comes from

Suppliers don't give away certainty for free. When they quote a fixed price, they're buying forward contracts to hedge their own exposure to your load — and they're adding a margin to cover the risk that your actual usage differs from your forecast. That margin is the "risk premium" embedded in every fixed-price quote.

The size of the premium depends on market volatility at the time you're quoting, the term length, and the predictability of your load. In a high-volatility environment, fixed-price premiums can be substantial. In a calm market, the premium is lower — and locking in a fixed rate is more attractive.

Index Contracts: Maximum Exposure, Maximum Flexibility

An index contract prices your supply at (or near) the real-time or day-ahead wholesale market rate — typically hourly or daily. You get the raw market price without a supplier risk premium. Over a long period, buyers on index contracts often pay less than fixed-price buyers — because they're not paying for certainty they don't need.

Who should consider index pricing

• Industrial facilities with flexible operations that can shift load away from peak-price hours
• Organizations with substantial on-site generation or storage that can manage around price spikes
• Buyers with strong cash reserves who can absorb a bad month without financial stress
• Sophisticated energy managers who track the market and can act on signals

The real risk of index pricing

Market spikes are not gradual. During cold snaps, heat waves, or grid emergencies, wholesale power prices can increase 10–100x within a matter of hours. A single extreme weather event can add more to your monthly bill than a full year of the fixed-price premium you were trying to avoid. Buyers on index contracts in Texas during Winter Storm Uri in 2021 faced bills 5–20x their normal amount. Budget for this scenario before choosing index pricing.

Blended / Layered Contracts: The Sophisticated Middle Ground

A blended or layered contract involves purchasing your supply in multiple tranches — some volume locked at a fixed price now, the remainder purchased at market rates at intervals over the contract term. This approach has two main benefits:

• You average your entry price over multiple market windows rather than betting everything on a single point in time.
• You retain partial upside — if prices fall after you've locked the first tranche, subsequent tranches are purchased at the lower level.

How layered purchasing works in practice

Imagine you have a 24-month supply contract starting in January. Instead of fixing the entire 24 months at today's rate, you fix 50% now. Six months later, you fix another 25%. And six months after that, you fix the remaining 25%. Your final rate is a weighted average of those three purchase prices. If the market moves down between purchases, you benefit. If it moves up, you're partially protected by what you already locked.

This approach requires more active management — either by your internal team or by your broker — and it works best for larger loads where the math of tranching is meaningful. For loads under $10,000/month, the complexity usually outweighs the benefit.

How Market Conditions Should Influence Your Choice

The "right" contract structure isn't static — it depends on where the market is when you're making the decision.

• When markets are historically elevated and the forward curve is backwardated (futures prices declining), floating or blended structures often outperform. Locking in a fixed rate at a market peak means paying that premium for the entire term.
• When markets are historically low and the forward curve is in contango (futures prices rising), fixing a long-term rate makes more sense. You're locking in a rate that the market expects to be more expensive later.
• When market volatility is high — regardless of absolute price level — fixed-price premiums are higher. If certainty is your goal, a high-volatility environment is an expensive time to buy it.

A Note on Contract Term

The structure decision and the term decision interact. A 36-month fixed-price contract locks in more certainty but at a higher risk premium (suppliers charge more to guarantee a price over a longer horizon). A 12-month fixed contract has a smaller premium but requires you to go back to market more frequently — which can be an advantage or a disadvantage depending on your market view.

Most commercial buyers end up on 12–24 month terms. Shorter than 12 months rarely makes sense unless you're in a market where prices are high and expected to fall sharply. Longer than 36 months introduces meaningful execution risk and is usually only worth considering for very large loads with predictable consumption.