West Midlands metals processor — flex portfolio, VO, solar and sub-metering

The starting position

A West Midlands metals processor running 24/7 operations, with electricity its largest controllable cost and significant exposure to wholesale price volatility. The existing arrangement was a single fixed-price electricity contract with a ±10% volume tolerance, renewing annually on a fixed date and re-quoted via a comparison-broker model.

The owner had been exploring solar PV for two years but the financial case kept stalling. The installer's model showed an attractive payback; the energy contract's take-or-pay clause meant the actual payback was much weaker because volume penalties claimed back most of the savings. The two pieces had never been modelled together.

What we changed, in order

1. Strategy and contract structure

We moved the business onto a full Flex Portfolio under a framework agreement. The volume tolerance was negotiated to zero, removing the take-or-pay penalty entirely. Triggers and caps were set at the start of the term, with non-commodity components selected individually for fix or pass-through treatment.

2. Voltage optimisation

A two-week voltage log showed the incoming supply was consistently above optimal. With the site's motor-heavy load, VO was a strong candidate. A unit was sized, modelled and installed during a planned outage. Sub-meters above and below the unit measured the actual savings, which tracked the forecast model within tolerance.

3. Roof solar

With the take-or-pay clause now removed and the underlying load reduced by VO, a properly sized roof solar array was financially viable. We designed the system around the new half-hourly load profile (rather than to fill the available roof), set up Smart Export Guarantee tariff competition, and configured proper export metering.

4. Per-line sub-metering

Each production line was sub-metered so the operations team could see consumption by line, by shift and by product type. Yolk aggregated the data and surfaced the highest-cost consumption windows — which informed shift planning and identified two pieces of equipment due for replacement on energy grounds alone.

5. SECR and CDP integration

The carbon reporting team brought all of the above into the annual SECR submission and CDP response. The improvements year-on-year were material and audit-clean.

What changed materially

• Energy spend: meaningfully lower than the year-prior baseline, with the larger contribution from procurement and the smaller from kit. Both compounded over the contract life.
• Take-or-pay risk: eliminated entirely, removing a ceiling on solar payback.
• Carbon footprint: Scope 2 emissions reduced materially via solar and VO. Reported clean in SECR; flagged for CDP scoring uplift.
• Operational visibility: finance and operations both gained much sharper visibility into which lines and shifts cost most to run.

What we'd do differently

On reflection, the order of interventions was almost right but slightly compressed. With more time we'd have sequenced the VO survey, install and verification into a quieter operational quarter rather than running them in parallel with the solar install. The savings still tracked the model, but the verification phase was tighter than ideal.

The lesson, in one sentence

On a manufacturing site, the contract structure, the on-site generation case and the efficiency kit are not three separate decisions — they're one decision, in three pieces. Modelling them together (which is what flex purchasing inside a TUS engagement makes possible) is what unlocks the full financial case.