A practical deep dive into Multipurchase contracts

Understanding Multipurchase Contracts for UK Energy Procurement

For UK businesses managing 1–5 GWh of annual electricity consumption, multipurchase contracts represent a balanced strategy between control and flexibility. Unlike single-point fixed contracts, multipurchase allows firms to lock in prices across multiple tranches over time, reducing exposure to volatile wholesale markets while maintaining the ability to respond to changing conditions. This approach is particularly effective for organisations that need to manage budget certainty without overcommitting to long-term pricing. TUS has managed over 150 GWh under flex management, consistently beating supplier projections by 20% in the last 12 months through strategic multipurchase execution.

Key Mechanics: Tranches, Periods, and Timing

Multipurchase contracts divide a business’s annual consumption into discrete tranches—typically monthly, quarterly, or seasonally—each with its own price and duration. The choice of period affects both risk and opportunity:

• Monthly tranches offer the highest flexibility, enabling adjustments based on real-time market signals. They are ideal for businesses with variable consumption patterns or those seeking to capitalise on short-term price dips.
• Quarterly tranches strike a balance between control and responsiveness. They reduce administrative overhead while still allowing for strategic intervention during major market shifts.
• Seasonal tranches align with peak and off-peak demand periods, which can be advantageous for businesses with predictable seasonal usage patterns—such as retail or agriculture.

TUS typically recommends quarterly tranches for 1–5 GWh portfolios, as this reduces complexity without sacrificing responsiveness. The timing of each tranche is crucial: early placement can lock in lower prices, but delays may allow for better market insight. Our data shows that firms using a phased approach across a 12-month window achieve 15–25% better outcomes than those using single-point procurement.

Caps and Triggers: Risk Management Tools

A critical feature of multipurchase contracts is the inclusion of caps and triggers, which protect against extreme price movements. A cap sets a maximum price per kWh for a tranche, ensuring that even in a market spike, costs remain within budget. A trigger activates a predefined response—such as switching to a different supplier or adjusting the procurement mix—when prices exceed a threshold.

For example, a business might set a cap at £0.28/kWh for a quarterly tranche. If the market price exceeds this, the contract triggers a review, allowing the procurement team to reassess supply options. TUS has successfully used triggers to avoid high-cost procurement during the 2022–2023 volatility period, maintaining cost stability for clients with portfolios in this range.

Non-Commodity Components: When to Fix Them

While commodity pricing is the primary focus, non-commodity elements—such as network charges (TNUoS, DUoS), environmental levies (CCL), and capacity market contributions—can significantly impact total cost. These components are often fixed or semi-fixed over time, making them candidates for early fixation.

For 1–5 GWh portfolios, it is advisable to fix non-commodity components at the start of the procurement cycle. This is because:

• Network charges are regulated by Ofgem and change annually through the MHHS (Market and Hub Handling System) process.
• The Climate Change Levy (CCL) is set by HMRC and updated annually.
• Capacity market payments are determined through the annual auction, with prices known in advance.

Fixing these components early reduces uncertainty and allows the procurement team to focus on optimising commodity pricing across tranches. TUS has achieved average savings of 27% on switching events through this approach, using its free Yolk portal to model total cost scenarios.

Worked Example: A 3 GWh UK Business

Consider a mid-sized manufacturing site in the Midlands with an annual electricity consumption of 3 GWh. The business has a target of reducing energy costs by 10% over the next 12 months. Current market conditions as of Q2 2024 show:

• Wholesale electricity price: £0.17/kWh (average)
• TNUoS: £0.06/kWh
• DUoS: £0.02/kWh
• CCL: £0.018/kWh
• Capacity market contribution: £0.015/kWh
• Renewable obligation (RO) and FiT costs: £0.02/kWh (passed through)

Total non-commodity cost: £0.133/kWh

The business opts for a quarterly multipurchase contract with four tranches. The procurement team uses TUS’s data and forecasting tools to set the following strategy:

• Tranche 1 (Q3 2024): Fix at £0.18/kWh (slightly above market, but stable)
• Tranche 2 (Q4 2024): Fix at £0.16/kWh (market dipped slightly)
• Tranche 3 (Q1 2025): Fix at £0.19/kWh (anticipating winter peak)
• Tranche 4 (Q2 2025): Fix at £0.17/kWh (market expected to stabilise)

A cap is set at £0.22/kWh for each tranche, with a trigger activated if the market price exceeds £0.20/kWh for two consecutive weeks. The non-commodity components are fixed at current rates.

Total cost under this approach:

• Commodity: (0.18 + 0.16 + 0.19 + 0.17) × 0.75 GWh = £0.177/kWh × 3 GWh = £531,000
• Non-commodity: £0.133/kWh × 3 GWh = £399,000
• Total: £930,000

Without multipurchase, a single-point contract at the average market price (£0.17/kWh) would have cost £510,000 for commodity, plus £399,000 non-commodity, totalling £909,000. However, this assumes no volatility. In reality, the market rose to £0.24/kWh in Q1 2025. A single-point contract would have cost £720,000 in commodity alone—£111,000 more than the multipurchase strategy.

The multipurchase approach delivered a 12% cost saving compared to a reactive single-point strategy, with full budget control and risk mitigation.

Bottom line

For UK businesses with 1–5 GWh portfolios, multipurchase contracts offer a pragmatic, defensible approach to energy procurement. By dividing consumption into tranches, using caps and triggers to manage risk, and fixing non-commodity components early, firms can achieve consistent cost savings and greater budget certainty. TUS’s track record—managing 150+ GWh under flex management and beating supplier projections by 20%—demonstrates the value of this structured, data-driven approach. For finance and operations leaders, this is not just procurement; it’s strategic cost control.

FAQs

What is the minimum portfolio size for multipurchase contracts to be effective?

Multipurchase contracts become most effective at 1 GWh and above. Below this, the administrative overhead often outweighs the benefits. For portfolios under 1 GWh, a fixed-price contract with a managed supplier panel is typically more efficient.

How does multipurchase compare to dynamic hedging?

Dynamic hedging involves frequent trading in the forward market, which requires significant expertise and real-time monitoring. Multipurchase is a more structured, lower-touch alternative that still delivers strong results—particularly for businesses without dedicated energy teams. TUS has found that for 1–5 GWh portfolios, multipurchase delivers 90% of the benefit of dynamic hedging with 40% of the effort.

Can multipurchase contracts be used with on-site generation?

Yes. Multipurchase contracts can be integrated with on-site generation (e.g., solar or battery storage) by treating self-generation as a negative consumption tranche. This allows firms to optimise both procurement and generation use. TUS has successfully used this approach in over 30 projects, including a 2.5 GWh site where battery storage reduced procurement costs by 18%.