Procurement

A practical deep dive into multipurchase contracts for UK businesses

Multipurchase contracts let organisations with 1‑5 GWh of annual demand lock in price bands while retaining flexibility to adjust volumes as business needs change. This article explains period choices, tranche structures, caps, triggers and the timing of non‑commodity fixes, and includes a worked example based on current UK market prices.

By TUS Trade Desk — Commercial Energy Consultants•Published 1 October 2026•6 min read

Thesis

Multipurchase contracts are a pragmatic way for mid‑size UK businesses to combine price certainty with the ability to respond to demand fluctuations, without the rigidity of a full‑volume fixed‑price deal. By layering commodity and non‑commodity components, and by using tranches, caps and triggers, you can protect your P&L against market spikes while still benefiting from volume optimisation.

How a multipurchase contract is built

Core components

Commodity component – the wholesale electricity price (e.g. the UK Power Exchange spot price). This is the variable part that moves with the market.
Non‑commodity component – network charges (TNUoS, DUoS), capacity market payments, Renewable Obligation Certificates (RO), and any ancillary services you wish to lock in.
Volume commitment – the total energy you agree to purchase over the contract term, typically expressed as a percentage of your forecast demand.

Why TUS is a strong partner

Access to a 30+ supplier panel, allowing us to source the most competitive commodity pricing.
In the last 12 months we beat supplier projections by 20 %, delivering real‑world savings.
Our Yolk portal provides transparent, real‑time data and has helped clients achieve an average 27 % switching saving.

Period choices – monthly, quarterly, seasonal

Period	Typical use case	Advantages	Considerations
Monthly	Businesses with volatile production schedules (e.g. food processing)	Fine‑grained alignment to actual consumption, quick reaction to market moves	Higher administrative overhead, more frequent settlement
Quarterly	Companies with stable but not static demand (e.g. retail chains)	Balance between flexibility and simplicity	May miss short‑term price spikes
Seasonal	Firms with clear seasonal patterns (e.g. agriculture, hospitality)	Aligns with natural demand cycles, reduces transaction cost	Less responsive to unexpected demand changes

Regulators such as Ofgem require transparent settlement processes for all these periods, and the DESNZ framework ensures that any capacity‑related charges are applied consistently across the contract term.

Tranches, caps and triggers

Tranche design

A tranche is a block of volume that is priced separately. For a 3 GWh portfolio you might define:

Tranche A – 0‑1 GWh, priced at the 12‑month forward curve.
Tranche B – 1‑2 GWh, priced at the 24‑month forward curve.
Tranche C – 2‑3 GWh, priced at the 36‑month forward curve. This structure mirrors the way SECR reporting allows businesses to disclose forward‑looking procurement strategies.

Caps and triggers

Cap – a maximum price you will pay for a tranche. If the market price exceeds the cap, the supplier absorbs the excess.
Trigger – a market price level that, when breached, automatically shifts a portion of volume to a higher‑priced tranche or activates a hedging instrument. Typical caps range from £45/MWh to £70/MWh depending on risk appetite and market outlook.

Fixing non‑commodity components

Non‑commodity elements are often less volatile than the wholesale price, but they can still represent a sizeable cost base. Best practice is to fix these early in the contract lifecycle:

Network charges – lock in TNUoS and DUoS rates at the start of the term; they are regulated by Ofgem and change only on a yearly basis.
Capacity market payments – secure a fixed rate for the portion of demand that falls within the Capacity Market auction price (currently around £20/MWh).
Renewable obligations – negotiate a fixed REGO price or a guaranteed volume of Renewable Obligation Certificates. Fixing these components reduces the number of variables that need to be tracked in the Yolk portal, making the contract easier to manage.

Worked example – a 2 GWh annual portfolio

Assume a manufacturing site with the following profile:

Annual demand: 2 GWh (≈5,480 MWh/month)
Preferred period: Quarterly
Risk appetite: Moderate – willing to accept a cap of £60/MWh on the commodity component.

Step 1 – Define tranches

Tranche	Volume (MWh)	Forward price used
A	0‑1,800	12‑month forward (£55/MWh)
B	1,800‑3,600	24‑month forward (£58/MWh)
C	3,600‑5,400	36‑month forward (£62/MWh)

Step 2 – Set caps and triggers

Cap: £60/MWh for all tranches.
Trigger: If the 12‑month forward exceeds £65/MWh, shift 10 % of Tranche A volume to Tranche B.

Step 3 – Fix non‑commodity costs

TNUoS: £12/MWh (fixed for 3 years)
DUoS: £5/MWh (fixed for 3 years)
Capacity: £20/MWh (fixed for contract term)
REGO: £6/MWh (fixed)

Step 4 – Calculate quarterly cost

Take Q1 as an illustration (1,370 MWh consumed).

Commodity cost – Assume spot price for the quarter averages £57/MWh, below the £60 cap.
- Cost = 1,370 MWh × £57 = £78,090
Non‑commodity cost – Sum of fixed charges:
- TNUoS = 1,370 × £12 = £16,440
- DUoS = 1,370 × £5 = £6,850
- Capacity = 1,370 × £20 = £27,400
- REGO = 1,370 × £6 = £8,220
- Total non‑commodity = £58,910
Total quarterly bill = £78,090 + £58,910 = £137,000

If the spot price spikes to £68/MWh in Q2, the cap activates:

Commodity cost = 1,370 × £60 = £82,200 (instead of £93,160)
Savings from the cap = £10,960, which the supplier absorbs.

Outcome

Over a 12‑month horizon the contract delivers a 5‑10 % average saving versus an unhedged spot purchase, with a payback period of 2‑3 years when compared to the incremental premium paid for the cap. These figures align with TUS’s broader voltage optimisation results (5‑15 % saving, 2‑3 year payback).

When to adopt a multipurchase contract

Demand range 1‑5 GWh – the volume is large enough to justify tranche design but not so large that a full‑volume fixed price is economical.
Variable production schedules – quarterly or monthly periods capture demand swings without excessive exposure.
Desire to lock non‑commodity costs – fixing network and capacity charges simplifies budgeting and reduces regulatory reporting effort under SECR and CIS.
Access to a strong supplier panel – TUS’s 30+ suppliers ensure competitive forward curves and the ability to negotiate favourable caps.

Risks and mitigation

Risk	Mitigation
Market price exceeds cap significantly	Use a trigger to shift volume to a later tranche or employ a short‑term hedge (e.g., a futures contract).
Supplier default	TUS conducts credit checks and spreads exposure across multiple suppliers in the panel.
Regulatory change (e.g., new capacity market rules)	Include a review clause at the 12‑month mark to renegotiate non‑commodity components.
Administrative burden of frequent settlements	Leverage the Yolk portal for automated data capture and reconciliation.

Bottom line

Multipurchase contracts give UK businesses with 1‑5 GWh of annual demand a balanced approach to price certainty and flexibility. By selecting the right period, structuring tranches with sensible caps and triggers, and fixing non‑commodity components early, you can achieve 5‑10 % cost reductions and protect your budget against market volatility. With TUS’s extensive supplier panel, proven track‑record of beating projections by 20 %, and a free data portal that delivers an average 27 % switching saving, the model is both defensible and operationally simple.