Fixed vs Flexible Business Energy Contracts

A fixed-price business energy contract is an agreement under which the unit rate for electricity or gas is set at the point of contract and remains unchanged for the duration of the contract term, regardless of how wholesale energy market prices move during that period. The standing charge may also be fixed, though the specific terms vary by supplier and contract.

Fixed contracts are the most common form of commercial energy supply agreement for small and medium-sized businesses. They offer a degree of price certainty that can assist with budgeting and financial planning, because the cost per unit of energy consumed is known in advance for the contract period.

Fixed contracts are typically available for terms ranging from one to five years, though the availability of longer terms and the pricing offered will depend on market conditions at the time of contracting. The price agreed at the point of contract reflects the supplier's view of wholesale costs, network charges, policy costs and margin at that time.

Flexible energy purchasing — sometimes referred to as structured purchasing, portfolio management or basket purchasing — is an approach under which a business does not fix its entire energy price at a single point in time. Instead, the commodity element of the price is built up through a series of forward purchases made over a period of time, typically managed by a specialist energy procurement consultant or broker.

Under a flexible arrangement, the business typically enters a framework contract with a supplier that sets out the non-commodity terms (network charges, capacity charges, supplier margin and other fixed elements), while the commodity price is purchased in tranches as market conditions develop. The aim is to spread the risk of buying at a single point in time, though this does not guarantee a lower overall price than a fixed contract.

Flexible purchasing is generally more complex to manage than a fixed contract. It requires a business to have sufficient consumption to make the approach commercially viable, appropriate governance arrangements to authorise purchasing decisions, and a clear understanding of the risks involved. It is not typically suitable for small or medium-sized businesses without specialist support.

Within the category of fixed contracts, there is an important distinction between fully fixed contracts and pass-through (or transparent) contracts. Under a fully fixed contract, the supplier fixes all elements of the price — including network charges, policy costs and other non-commodity elements — for the duration of the term. The business pays the same unit rate regardless of changes to these underlying costs.

Under a pass-through contract, the commodity element of the price is fixed, but certain non-commodity costs — such as network charges, balancing charges or policy levies — are passed through to the customer at cost as they change. This means the total unit rate can vary during the contract term, even though the commodity element is fixed. Pass-through contracts can offer a lower initial price than fully fixed contracts, but they carry more price variability.

Understanding whether a contract is fully fixed or pass-through is important when comparing quotations. A lower headline unit rate on a pass-through contract may not result in a lower total cost than a higher headline rate on a fully fixed contract, depending on how non-commodity costs move during the term. Free Energy Help can help businesses understand the structure of quotations received.

One of the principal characteristics of a fixed-price contract is the degree of price certainty it provides. For many businesses, particularly those with tight margins or limited capacity to absorb cost increases, knowing the cost of energy for the next one to three years can be a significant operational benefit. It allows energy costs to be budgeted with greater confidence and reduces exposure to short-term wholesale market volatility.

However, price certainty is not the same as price optimisation. A fixed contract agreed at a time when wholesale prices are elevated will lock in those elevated costs for the duration of the term, even if market prices subsequently fall. Conversely, a contract agreed when prices are low will protect the business if prices subsequently rise. The outcome depends on market conditions at the time of contracting and how those conditions develop.

Flexible purchasing strategies seek to reduce the risk of contracting at a single unfavourable point in time by spreading purchases over a period. However, this approach introduces a different form of uncertainty — the final blended price is not known until all tranches have been purchased, and the outcome depends on the purchasing decisions made and the market conditions prevailing at each point.

Fixed-price contracts are generally straightforward in structure. The key commercial terms — unit rate, standing charge, contract duration and any break or exit provisions — are agreed at the outset and documented in the supply agreement. The business knows what it will pay per unit for the duration of the term, subject to any pass-through elements.

Flexible purchasing arrangements are considerably more complex. They typically involve a framework supply agreement, a separate purchasing mandate or authority document, and an ongoing relationship with a procurement consultant or broker who manages the purchasing programme. The terms of the framework contract, the purchasing strategy, the reporting arrangements and the fee structure all require careful review.

The complexity of flexible arrangements means they require more management time and resource than fixed contracts. Businesses entering flexible arrangements should ensure they have appropriate internal governance, clear lines of authority for purchasing decisions, and regular reporting from their procurement adviser. The contractual documentation should be reviewed by a suitably qualified adviser before commitment.

Accurate consumption forecasting is important for both fixed and flexible contracts, but it is particularly critical for flexible purchasing arrangements. Under a flexible arrangement, the business typically commits to purchasing a defined volume of energy over the contract period. If actual consumption differs significantly from the forecast volume, there may be financial consequences — either from over-purchasing or under-purchasing relative to the contracted volume.

Fixed contracts generally offer more tolerance for consumption variation, though the specific terms vary. Some fixed contracts include volume tolerance provisions that allow actual consumption to vary within a defined range without penalty. Others may include take-or-pay provisions or reconciliation mechanisms. Understanding the volume tolerance terms of any contract is important before committing.

Businesses with highly variable or unpredictable consumption profiles should consider carefully whether a flexible purchasing arrangement is appropriate, and should discuss consumption forecasting and volume tolerance with their procurement adviser before entering any arrangement.

Volume tolerance refers to the degree to which actual consumption can vary from the contracted or forecast volume without triggering additional charges or financial adjustments. Different contract structures handle volume variation in different ways, and the specific terms can have a material impact on the total cost of supply.

Under some fixed contracts, a degree of volume tolerance is built in — for example, the contract may allow actual consumption to be within a defined percentage of the forecast volume without penalty. Outside that tolerance band, the business may pay a different rate for the excess or shortfall, or there may be a reconciliation at the end of the contract period.

Flexible purchasing arrangements typically have tighter volume tolerance requirements, because the purchasing programme is designed around a specific volume profile. Significant deviations from the forecast volume can affect the economics of the arrangement and may result in additional costs. Businesses should discuss volume tolerance in detail with their procurement adviser and ensure they understand the financial implications of consumption variation.

Flexible purchasing is generally more appropriate for larger energy users — typically businesses consuming above a certain annual threshold of electricity or gas — where the potential benefit of an optimised purchasing strategy is sufficient to justify the additional complexity, management time and advisory costs involved. The threshold at which flexible purchasing becomes commercially viable varies, and businesses should seek specialist advice on whether their consumption profile is suitable.

Flexible purchasing may also be more appropriate for businesses that have the internal governance and resource to manage an active purchasing programme, a clear understanding of energy market dynamics, and a risk appetite that is consistent with accepting ongoing market exposure. It is not suitable for businesses that require complete price certainty, have limited management resource, or are not in a position to make timely purchasing decisions.

It is important to note that flexible purchasing does not guarantee a lower cost than a fixed contract. The outcome depends on market conditions, the quality of the purchasing strategy and the timing of purchasing decisions. Businesses considering flexible purchasing should obtain independent specialist advice and should not enter such arrangements on the basis of projected savings alone.

The choice between a fixed and flexible contract is not a question of which is objectively better — it is a question of which is more appropriate for a particular organisation at a particular time, given its consumption profile, risk appetite, governance capacity, budget requirements and market outlook. A contract structure that works well for one business may be entirely unsuitable for another.

Factors that may influence the appropriate contract structure include the size and predictability of the business's energy consumption, the importance of cost certainty for budgeting and financial planning, the business's capacity to manage an active purchasing programme, its tolerance for price risk, and the current state of the wholesale energy market.

Free Energy Help does not recommend one contract type over another as a general proposition. Our role is to help businesses understand the options available, obtain quotations from a broad panel of UK commercial energy suppliers, and make an informed decision based on their own circumstances and objectives. We recommend that businesses seek independent specialist advice before committing to any procurement strategy.

Free Energy Help works with a broad panel of UK commercial energy suppliers to obtain competitive quotations for business electricity and gas. We can present fixed-price quotations across a range of contract terms, allowing businesses to compare the options available in the market at the time of their renewal or switch.

For businesses interested in understanding whether flexible purchasing may be appropriate for their consumption profile and circumstances, we can provide general information and, where appropriate, refer them to specialist flexible procurement advisers. We do not manage flexible purchasing programmes directly.

Our service is free to the business customer. We are remunerated by the supplier on contracts placed. We will always disclose the basis of our remuneration on request. Our aim is to help businesses make an informed decision about their energy procurement, not to recommend a particular contract type or supplier.