Combined Heat and Power Quality Assurance (CHPQA) Programme Guidance

The Combined Heat and Power Quality Assurance (CHPQA) programme is DESNZ's certification scheme for combined heat and power (CHP) plants across Great Britain. Operators self-assess their schemes annually against efficiency thresholds — principally a Quality Index of 100 and a minimum 20% power efficiency — to earn 'Good Quality CHP' status.

Certification unlocks significant fiscal benefits: Climate Change Levy (CCL) exemption, Carbon Price Support (CPS) reduction, business rates relief on qualifying plant and machinery, and eligibility for renewable support under the Renewables Obligation (RO) and Contracts for Difference (CfD). For a 150 MW plant, these benefits can exceed £13 million annually.

Between 26–27 March 2026, DESNZ republished its entire CHPQA guidance suite — 30 numbered guidance notes, 4 simplified guides, several appendices, a unit list, a version control index, and the CHPQA Standard itself. Most documents were updated to versions 6–8.

The trigger appears to be the launch of a new CHPQA self-assessment portal, replacing the legacy digital service. The previous submission forms (F1–F4) are now redundant. This is a consolidation and modernisation exercise rather than a substantive policy change — the core thresholds and methodology remain broadly unchanged.

Programme overview and portal

• Simple guide to the CHPQA programme — how to register, submit, and claim benefits; covers simple vs complex scheme routes

• Guidance Note 0: Introduction (v8) — full instructions for self-assessment and certification via the new portal

• Guidance notes version control index 2026 — master list of all 30 active guidance notes with current version numbers

The CHPQA Standard

• CHPQA Standard — sets the Quality Index thresholds that define 'Good Quality CHP'; different issues apply depending on when a scheme commenced operation or entered a CfD contract (Issue 5 for pre-2013, Issue 6 from 2016, Issue 7 from December 2018 for CfD schemes)

Scheme setup and definition (Notes 1–3)

• Note 1: Registration — creating portal accounts and obtaining a CHPQA reference number

• Note 2: Scheme description — administrative requirements for equipment lists and capacity calculations

• Notes 3 and 3s: Self-assessment for new/upgraded schemes — design submission requirements for complex (>2 MWe) and simple (≤2 MWe) schemes respectively

• Note 11: Scheme definition — how to draw scheme boundaries around utilities and process areas

• Note 12: Scheme description (technical) — line diagrams, equipment tagging, heat profiles

Monitoring and measurement (Notes 13–23)

• Note 13: Monitoring — metering requirements by scheme size, accuracy standards (2.0–4.5%)

• Notes 14–16: Energy inputs, power outputs, heat outputs — how to measure and classify each

• Notes 17–19: Uncertainty — calculating measurement uncertainties, acceptable thresholds, and adjustment factors that penalise excessive uncertainty

• Notes 20–22: Indirect determination — fallback methods for fuel inputs, heat outputs, and mechanical power when direct metering is unavailable

• Note 23: Bias correction — detecting and correcting systematic measurement errors

Quality and qualification calculations (Notes 10, 24–28)

• Note 10: Key criteria — Quality Index thresholds (100 annual, 95 initial, 105 new capacity) and 20% power efficiency minimum

• Note 24: Determination of scheme quality — how to calculate the Quality Index

• Note 25: Qualifying fuel input — formula for schemes failing the 20% power efficiency threshold

• Note 26: Qualifying power output — reduced qualifying output calculation for schemes below QI threshold

• Note 27: Qualifying power capacity — minimum operational hours (500–1000 annually) and capacity calculations

• Note 28: Z-ratio determination — measuring the power-heat trade-off in steam turbine extraction, with reference tables for turbines from 2–50+ MWe

Alternative fuels and special cases (Notes 29–31, 50)

• Note 29: Alternative fuels — measurement methods for biomass, waste, and gaseous fuels using gross calorific value

• Note 30: Community heating — qualifying criteria for CHP serving residential heat networks (>60% residential heat threshold)

• Note 31: Schemes ≤2 MW — simplified three-data-point assessment for small schemes

• Note 50: Useful heat outputs — evidence requirements distinguishing 'typical' from 'atypical' heat loads (18.5% IRR threshold for atypical)

Fiscal benefits (Notes 41–44, 61)

• Note 41: CCL exemption and fuel duty relief — claiming tax benefits including Carbon Price Support liabilities for schemes above 2 MWe

• Note 43: Business rates exemption — scope of relief covering generation equipment but excluding heat recovery plant

• Note 44: Renewables Obligation and CfD — quality index calculations for biomass/waste CHP schemes accessing RO or CfD support

• Note 61: Fiscal benefits reporting — annual reporting requirement for benefits received, supporting policy review

Appendices and reference material

• Appendix 3 — worked example for direct use of gas turbine exhaust gases in industrial drying

• Appendix 4 — worked example for Z-ratio determination through plant performance testing

• Generic energy flow diagrams — standardised templates for reciprocating engine CHP submissions

• Unit list — 88 pre-approved small engines (≤500 kWe) from manufacturers including ABB, Bosch, and Cogenco, with efficiency ratings of 69–91%

• Simple guides (eligibility, monitoring, uncertainty) — plain-language summaries of the technical guidance for smaller operators