TDR Band Optimiser
Find TNUoS savings by right-sizing MIC to drop into a lower TDR band, then project savings across three years including the RIIO-3 rate uplift.
For energy consultants, procurement managers and finance teams reviewing HV and EHV site capacity agreements.
Try TDR Band OptimiserBand 2 · 487 kVA
recommended target, 49.5% lower annual TNUoS vs Band 3
3-year saving, Band 3 to Band 2 · 49.5% annual reduction
3-year savings projection
RIIO-3 rate impact (April 2026)
| RIIO-2 (2025-26) | RIIO-3 (2026-27) | |
|---|---|---|
| Band 3 · 1,200 kVA | £54,677/yr | £103,780/yr |
| Band 2 · 487 kVA | £27,594/yr | £52,380/yr |
| Annual saving | £27,083 | £51,400 |
The journey
Four steps, one optimised capacity
From MIC and peak demand to a target band, a safe target kVA, and a 3-year saving.
Enter
Enter MPAN, MIC and peak demand
Drop in the MPAN, select the voltage level, then enter the current MIC from the connection agreement and the actual maximum demand recorded over the last 12 months. That is all the tool needs.
Identify
Identify current TDR band and annual cost
We decode the MPAN to confirm the DNO region and voltage, then place the site in its current TDR band. The annual TNUoS cost at the current MIC is shown alongside how far above the safe minimum the MIC actually sits.
Recommend
Recommend optimal band and target MIC
All TDR bands for the voltage level are ranked by annual cost. The tool identifies which band the site can safely reach and calculates a target MIC with a 5% headroom buffer above actual peak demand.
Project
3-year savings with RIIO-3 impact
Savings are projected year by year. TDR rates nearly double under RIIO-3 from April 2026, which means acting before that date significantly increases the value of an MIC reduction. The RIIO-3 table shows exactly what is at stake.
Band 2 · 487 kVA
recommended target, 49.5% lower annual TNUoS vs Band 3
3-year saving, Band 3 to Band 2 · 49.5% annual reduction
3-year savings projection
RIIO-3 rate impact (April 2026)
| RIIO-2 (2025-26) | RIIO-3 (2026-27) | |
|---|---|---|
| Band 3 · 1,200 kVA | £54,677/yr | £103,780/yr |
| Band 2 · 487 kVA | £27,594/yr | £52,380/yr |
| Annual saving | £27,083 | £51,400 |
The problem
Your clients are probably paying too much for TNUoS
TDR (Transmission Demand Residual) charges are based on agreed capacity, not actual usage. Many businesses have MICs set years ago that far exceed their actual peak demand. With RIIO-3 rates nearly doubling from April 2026, oversized capacity is about to get very expensive.
Without reviewing MIC against actual demand, your clients will overpay by thousands - or tens of thousands - every year. And with RIIO-3, those overpayments are about to double.
Why it matters
What you walk away with
Current vs Optimal Band Comparison
See exactly which TDR band you should be in based on actual demand, with clear savings figures.
Target MIC Recommendation
Get a recommended MIC value that maintains a safety margin above peak demand.
RIIO-3 Impact Analysis
Compare current rates with April 2026 rates to understand the urgency of acting now.
3-Year Savings Projection
See cumulative savings over 3 years with year-by-year breakdown - perfect for client proposals.
Built on official published rates
FAQ
Answers, before you ask
TDR (Transmission Demand Residual) is a fixed daily charge based on your agreed capacity. Many businesses have MICs set years ago that are much higher than their actual demand, meaning they overpay significantly.
Still curious? Email [email protected]
Find the band your MIC should be in.
Enter MIC and peak demand, see the target band, the target kVA, and the 3-year saving before and after RIIO-3.