Commercial energy customers in deregulated markets have three rate structure options: a fixed rate, which locks in a set price for the duration of a contract term; an index rate, which floats with wholesale market pricing in real time; or a hybrid structure, such as block-and-index, which fixes a portion of load while leaving the remainder market-exposed. Each carries a distinct risk and reward profile. This article outlines how each works, which businesses are best suited for each structure, and how to determine which approach fits your organization’s financial reality and risk tolerance.
What Does It Mean To Lock In Energy Rates?
Now, you might be asking yourself, “What is locking in a power rate?”. Great question! It does seem intriguing that you can fix your electricity costs for a long period of time when electricity prices change daily. In order to fully understand how retail energy suppliers are able to offer fixed energy rates, one must comprehend the energy futures market.
In the world of finance, futures markets exist so that two counterparties can agree upon a certain price for a long period of time without having to worry about the fluctuations of daily market prices. Take a food manufacturer that relies heavily on sugar to make a product. It would be very difficult to sell a finished product at a stable price if the cost of sugar is constantly changing. So, the manufacturer might enter into a futures contract with a sugar supplier in order to fix the cost of sugar for a long period of time.
The electricity market is no different. Because electricity futures trade nearly ten years into the future, retail energy suppliers are able to purchase energy on your behalf for an extended period of time. They then, in turn, sell that same electricity to you for a predetermined fixed price.
Fixed Energy Rate Plans
A fixed-rate energy plan locks in a set price per unit of electricity or natural gas for the full duration of a supply contract, typically ranging from 6 to 60 months, depending on the market and supplier. Regardless of what happens to wholesale energy prices during that period, the contracted rate does not change. For businesses that treat energy as a fixed operating expense on their income statement, this structure removes one of the most unpredictable cost variables from their budget equation entirely.
Fixed-rate plans are the most commonly selected structure among commercial energy customers, and for good reason. Businesses where energy cost predictability directly supports operational and financial stability include:
- Restaurants and food service operators
- Hotels and hospitality businesses
- Gyms and fitness facilities
- Commercial and office buildings
- Retail stores and franchise operators
- Healthcare facilities and medical offices
- Educational institutions and nonprofits
These organizations share a common characteristic – their ability to absorb mid-year energy cost increases is limited, and the financial consequences of rate volatility outweigh the potential upside of floating the market.
Pros:
- Budget Certainty for Single and Multi-Year Planning: A fixed rate allows finance and operations teams to forecast energy costs with precision across the full contract term. For organizations managing annual budgets, multi-year capital plans, or investor reporting requirements, knowing the exact cost per kilowatt-hour or therm for the next 24 or 36 months eliminates financial uncertainty.
- Protection from Market Volatility: Fixed-rate supply contracts insulate customers from wholesale market price spikes driven by weather events, fuel supply disruptions, and demand surges.
- Market Timing Advantage: When fixed rates are executed at or near cyclical lows in the forward market, customers lock in a pricing advantage that compounds over the full contract term. In a rising market, a well-timed fixed-rate contract delivers savings relative to index pricing and future renewal rates.
- Simplified Procurement and Billing: Fixed-rate plans eliminate the need to monitor market conditions continuously or manage exposure to index price movements. Billing is predictable and consistent, reducing administrative complexity for accounting and operations teams.
Cons:
- Opportunity Cost If Market Prices Decline: The primary risk of a fixed-rate contract is that wholesale market prices drop materially after the agreement is executed. A customer locked into a fixed rate above current market levels is effectively paying a premium relative to index for the remainder of the term, with no ability to capture the lower pricing without paying an early termination fee.
- Early Termination Penalties: Fixed-rate energy contracts are binding commitments. Exiting before the expiration date typically triggers an early termination fee calculated based on remaining contract volume and the spread between the contracted rate and current market pricing. These penalties can be substantial, and they are rarely negotiable after the fact. Understanding the ETF structure before signing is an essential step in evaluating any fixed-rate supply agreement.
Variable (Index) Energy Plans
A variable or index-based energy plan prices electricity and natural gas at or near wholesale market rates rather than locking in a fixed price for a defined term. Instead of paying a predetermined rate per unit, customers on index plans pay whatever the market is delivering during each billing period.
How Index Pricing Works
In electricity markets, index pricing is typically tied to the Locational Marginal Price (LMP), the real-time cost of supplying the next megawatt-hour of electricity at a specific point on the grid, accounting for generation costs, transmission congestion, and energy losses. Customers on index plans may be priced against the day-ahead market, which sets prices for each hour of the following day based on forecasted supply and demand, or against the real-time market, which reflects actual grid conditions as they occur and is subject to greater hour-to-hour volatility.
Other regulatory fees, such as capacity, network transmission, and ancillary services, may be passed through at cost as separate line items.
In natural gas markets, index pricing is typically tied to a published benchmark, most commonly the Henry Hub spot price or a regional pipeline index, that reflects prevailing wholesale supply and demand conditions at the delivery point.
Index customers see their effective energy rate change month to month, sometimes significantly, based on weather patterns, fuel supply conditions, demand events, and grid reliability factors, none of which are within the customer’s control.
Which Businesses Benefit From Index Pricing
Index plans are not appropriate for every commercial energy customer, but they are a rational choice for businesses whose financial structure accommodates exposure to wholesale market pricing. Businesses that tend to be well-suited to index or market-based rate structures include:
- Oil refineries and petrochemical facilities
- Liquefied natural gas plants
- Manufacturing operations that price energy into their product cost
- Cold storage and refrigerated warehouse facilities
- Large industrial processors with flexible load profiles
- Businesses with in-house energy management and market monitoring capabilities
The common thread across these industries is that energy is treated as a cost of goods sold rather than a fixed operating expense. When energy costs rise, product pricing can often be adjusted to reflect the change. When energy costs fall, margins improve. This pass-through dynamic makes index exposure a manageable pricing structure.
When Index Has Beaten Fixed
Over extended periods, index pricing has historically outperformed fixed-rate contracts for customers who maintained consistent index exposure across market cycles. The core argument for floating the market rests on the observation that retail fixed rates embed a supplier margin and a forward market risk premium, meaning that over time, a customer paying fixed is paying more than index prices to compensate the supplier for assuming pricing risk on their behalf.
Prior to 2021, energy markets in many regions trended relatively flat. Customers who remained on index through that period often paid less in aggregate than customers who locked in fixed rates repeatedly across the same period.
However, the post-2021 market environment has tested this assumption materially. The convergence of the European energy crisis, domestic supply constraints, record-high PJM capacity auction results, and AI-driven load growth has produced a sustained period of elevated energy prices that has significantly eroded the historical advantage of floating the market. Index customers who were exposed during the 2021–2026 price cycle absorbed costs that fixed-rate customers were largely insulated from. This does not invalidate the long-term case for index pricing among appropriate customers, but it does illustrate that the risk/reward profile of floating the market is highly dependent on when in the price cycle that exposure begins and how long it is maintained.
Risk and Reward Profile
The index pricing decision ultimately comes down to a straightforward risk/reward assessment:
- Upside: When wholesale market prices are low or declining, index customers capture savings that fixed-rate customers cannot access during their contract term. Over favorable market cycles, this advantage can be substantial.
- Downside: When wholesale prices spike, driven by extreme weather, supply disruptions, or market changes, index customers absorb those increases without protection. Unlike fixed-rate customers who are insulated for the duration of their contract, index customers face full market exposure in real time.
- Organizational requirement: Managing index exposure effectively requires either a high tolerance for cost variability, the financial structure to absorb market spikes, or active market monitoring and the ability to convert to a fixed or hybrid structure when conditions warrant. For most small to mid-sized commercial customers without dedicated energy management resources, unmanaged index exposure introduces more risk than the potential savings justify.
Hybrid Energy Products: Block + Index
For commercial and industrial energy customers who find the fixed vs. index decision too binary for their actual usage profile and risk tolerance, block-and-index products offer a structured middle ground, combining the price certainty of a fixed contract with the market flexibility of index exposure in a single supply agreement.
How Block + Index Works
A block-and-index contract divides a customer’s total energy load into two distinct components. The “block” portion is purchased at a fixed price for a defined forward period, locking in cost on specific volumes regardless of market movements. The “index” portion floats with wholesale market pricing, typically tied to a published benchmark like the day-ahead LMP for electricity or a regional pipeline index for natural gas.
The split between fixed and indexed volume is negotiated based on the customer’s load profile, risk tolerance, and market view at the time of contract execution. A customer might fix 70% of their expected load and leave 30% indexed, or structure the split in volume blocks.
The block can sized to cover a customer’s predictable base load, on-peak load, or seasonal load, while the indexed portion covers load that fluctuates with production schedules, seasonal demand, or other operational factors.
How It Splits Risk
The block-and-index structure is designed to capture the primary benefit of each rate type while limiting the primary downside of each. The fixed block eliminates price uncertainty on the customer’s core load, insulating that portion of consumption from market spikes. The indexed portion retains market exposure on the variable load, which can generate savings when spot prices are low, off-peak pricing is favorable, or when the customer has operational flexibility to shift consumption to lower-cost periods.
The net effect is a blended cost that moves with the market to a degree but within a range that is more predictable and manageable than pure index exposure. In a rising market, the fixed block provides a meaningful cost floor. In a declining market, the indexed portion allows the customer to capture some of the benefit without being locked into a fully fixed rate that no longer reflects market conditions.
Why Block + Index Is Popular with Large Commercial Accounts
Block-and-index products are particularly well-suited to large commercial and industrial customers for several reasons.
First, at higher usage volumes, the financial impact of rate structure decisions is amplified. A small improvement in the effective rate per unit across large consumption produces meaningful savings.
Second, large commercial accounts typically have more predictable base load profiles, making it easier to size the fixed block accurately without over-or under-hedging.
Third, organizations with dedicated energy management resources or broker support are better positioned to monitor the indexed portion actively and act when market conditions warrant a structural adjustment.
When to Consider a Block + Index Structure
A block-and-index product deserves serious consideration in several specific scenarios:
- Forward market prices are elevated and locking 100% of load at a fixed rate feels like poor market timing.
- The customer’s load profile has a clearly identifiable base load component that can be fixed with confidence, and a variable component that benefits from market flexibility
- The business has some ability to shift energy-intensive operations to off-peak hours, making the indexed portion of the load more manageable and cost-effective
- A fixed-rate renewal is approaching but the forward curve suggests prices may improve
- The customer wants to introduce energy cost management sophistication beyond a standard fixed-rate renewal without taking on the full complexity of a pure index position
For a full breakdown of the energy supply product options available to commercial customers, including fixed, index, block-and-index, and other structured products, visit our energy supply products guide.
Comparison Table: Fixed vs. Variable vs. Hybrid Energy Rates
The table below compares the three primary commercial energy rate structures across the factors that matter most for procurement decision-making.
| Fixed Rate | Variable (Index) Rate | Hybrid Rate (Block + Index) | |
|---|---|---|---|
| How It’s Priced | Set price per unit for full contract term |
Floats with wholesale market (LMP, day-ahead, real-time) | Fixed block + indexed portion split by load volume |
| Price Certainty | High – rate does not change during term | None – rate changes each billing period | Partial – fixed on block, variable on index portion |
| Budget Predictability | High – costs fully forecastable | Low – costs fluctuate with market conditions | Moderate – base load predictable, variable portion fluctuates |
| Market Upside Potential | None – locked in regardless of market movement | Full – captures market lows in real time | Partial – indexed portion captures market improvement |
| Downside Protection | Full – insulated from market spikes for contract term | None – fully exposed to price spikes and volatility | Partial – fixed block insulates core load from volatility |
| Contract Term | 6–60 months | Month-to-month or short-term | Typically 12–36 months |
| Early Termination Risk | High – ETFs apply if exited before expiration | Low – short-term commitments lapse naturally | Moderate – depends on fixed block term and structure |
| Active Management Required | Low – rate is set at execution | High – requires ongoing market monitoring | Moderate – indexed portion benefits from active oversight |
| Best Market Condition | Low or backwardated forward prices | High prices expected to decline; favorable spot conditions | Elevated markets where full commitment feels premature |
| Risk Tolerance | Low – appropriate for risk-averse organizations | High – requires financial tolerance for cost variability | Moderate – balances certainty with market flexibility |
| Energy Treated As | Fixed operating expense | Cost of goods sold | Either – depends on load split and financial structure |
| Best For | SMBs, budget-sensitive operators, multi-year planners | Large industrials, manufacturers, businesses with pass-through pricing | Large commercial accounts, sophisticated buyers, transitional procurement periods |
Can I Switch From Index To Fixed In The Middle Of A Contract?
Yes! If you first decide to enroll in an index-based energy plan but decide that a fixed-rate suits your needs better, you can always roll your contract into a fixed rate. However, if you signed a fixed-rate contract, it can be quite difficult to unwind that agreement and turn it into a market-based agreement. Often, there are early termination penalties associated with breaking a fixed-rate energy contract. You may, however, be able to negotiate a blend and extend the contract with your existing supplier that allows you to change the rate and type of agreement. You should consult with an energy broker for guidance before exploring this option.
When Is the Best Time to Lock In Energy Rates?
Timing a fixed-rate energy contract well is one of the highest-value decisions a commercial energy buyer can make, and one of the most commonly mishandled. The honest answer to “when should I lock in?” is more nuanced than “when the market is low.” It requires understanding seasonal pricing patterns, reading forward curve signals, and monitoring commodity-specific indicators that drive electricity and natural gas prices in your market.
Seasonal Procurement Windows
Historically, the best time to lock in electricity rates and the best time to lock in natural gas rates have both followed seasonal patterns tied to demand cycles. Energy prices tend to be more favorable during the spring and fall shoulder seasons due to heating and cooling demand being at their lowest. Summer peak demand from air conditioning load and winter demand from heating tend to push both electricity and natural gas prices higher, making those periods generally less favorable for fixed-rate execution.
For natural gas, the timing dynamics are closely tied to storage inventory levels and winter supply risk. The late summer and early fall period, before winter storage withdrawals begin, can present favorable natural gas procurement windows, particularly when storage levels are adequate and winter supply risk is not yet being aggressively priced into forward markets.
It is important to note that these seasonal patterns are tendencies, not guarantees. In recent years, structural market changes, including increased LNG export demand, AI-driven electricity load growth, and tighter domestic supply, have introduced volatility that does not always follow historical seasonal norms.
Reading Futures Curves for Timing Signals
The most reliable timing signal available to commercial energy buyers is the forward curve itself, Two curve structures are particularly relevant for procurement timing decisions:
- Backwardation: When near-term prices are higher than forward prices, suggesting the market expects prices to decline over time.
- Contango: When forward prices are higher than near-term prices, signaling that the market expects prices to rise.
Monitoring the shape and direction of the forward curve, not just the current spot price, is the most actionable basis for procurement timing decisions.
Natural Gas Specific Timing: Storage Reports and Seasonal Spreads
For natural gas procurement specifically, the best time to lock in rates is influenced by several commodity-specific indicators that electricity buyers do not always track:
- Weekly EIA Storage Reports: The U.S. Energy Information Administration (EIA) publishes weekly natural gas storage data that measures the volume of gas held in underground storage facilities relative to the five-year average. Storage levels significantly above the seasonal average tend to suppress near-term natural gas prices. Storage deficits relative to historical norms signal tighter supply conditions and tend to support higher prices.
- Winter/Summer Spread: The spread between winter forward prices and summer forward prices in the natural gas market reflects the market’s expectation of seasonal demand differentials. When the winter premium over summer is narrow, it may indicate that near-term winter supply risk is not heavily priced in, potentially presenting a favorable window to lock in winter-delivery natural gas supply before that risk premium builds.
- LNG Export Dynamics: U.S. LNG export volumes now represent a material component of domestic natural gas demand. Periods of high LNG export activity tighten domestic supply and support higher spot and near-term forward prices. Monitoring export facility utilization and capacity additions provides additional context for natural gas procurement timing decisions.
Why Broker-Assisted Market Monitoring Is Critical
The forward curve structure, seasonal patterns, storage inventory levels, and LNG export dynamics described above require continuous monitoring. A procurement window that appears in the spring forward market may close within weeks as market conditions shift. A favorable entry point identified through storage data may be gone by the time a renewal process is initiated without adequate lead time.
Most commercial energy customers do not have the bandwidth, market access, or analytical tools to monitor these signals consistently between procurement cycles. This is precisely where an experienced energy broker delivers value that extends well beyond the initial contract negotiation. Diversegy monitors forward energy markets on an ongoing basis across electricity and natural gas, tracks seasonal pricing patterns in every deregulated market we operate in, and positions our customers to act when conditions align with their procurement objectives.
Need Help Navigating Your Next Fixed-Rate Energy Contract?
In conclusion, there are many benefits to locking in an energy price for your business. Our team of energy market experts can advise you on energy market price trends, the different types of fixed-rate contracts available, and how long to fix your energy rates. Contact us today to explore your options.
