The metric
GCC = lifetime kgCO2e displaced / grant £ requested. A scheme at the £325/tCO2e ceiling has a GCC of 1,000 / 325 = 3.08 kgCO2e/£. Salix-portal applications report GCC as the headline number; the £325/tCO2e ceiling is the value-for-money read of the same calculation [DESNZ].
Calculation
- Annual kWh fossil-fuel displaced × kgCO2e/kWh emission factor.
- Multiplied by % of demand actually replaced (heat-pump SCOP factored).
- Multiplied by asset life (typically 20 years).
- Divided by grant £ requested.
Difference vs the £325/tCO2e ceiling
£/tCO2e is the price-per-tonne lens; GCC is the tonnes-per-£ lens. Both are reported. A scheme that passes the £325 lens necessarily passes a 3.08 kgCO2e/£ GCC threshold.
Feasibility inputs needed
- Site survey + heat-loss model (W/m²).
- Annual fossil-fuel consumption (12-24 months).
- Proposed measure schedule with manufacturer SCOP / efficiency data.
- Lifetime convention and emission factor source.
See: £325 ceiling, estimator, feasibility, glossary.