PSDS for schools: PSC scheme guide, £510 ceiling, eligibility wizard

Grant Carbon Cost (GCC) threshold in the Salix portal

Grant Carbon Cost is the scoring metric Salix uses in the portal. It is the inverse of £/tCO2e: kgCO2e displaced per £ of grant. The two move together but appear in different boxes of the Salix-portal scoresheet [Salix].

Oliver Wakefield-Smith

Founder · Digital Signet

Verified for Phase 4 (final phase) · refresh expected on any Salix or DESNZ policy change

The metric

GCC = lifetime kgCO2e displaced / grant £ requested. A scheme at the £510/tCO2e Phase 4 ceiling has a GCC of 1,000 / 510 = 1.96 kgCO2e/£. Salix-portal applications report GCC as the headline number; the £/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 £510/tCO2e ceiling

£/tCO2e is the price-per-tonne lens; GCC is the tonnes-per-£ lens. Both are reported. A scheme that passes the £510 lens has a GCC of at least 1,000 / 510 = 1.96 kgCO2e/£.

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: £510 ceiling, estimator, feasibility, glossary.