District Heating

NHS Trusts may be able to benefit from exporting excess heat on to a district heating system for use by external organisations. In particular, where Combine Heat and Power (CHP) systems are oversized in order to produce more heat than would be required based on the site’s own demand.

Estimates for the costs and savings associated with this technology were derived from EEVS’ database of energy efficiency projects in the NHS.

The cost and carbon savings associated with expected reductions in kWh consumption were extrapolated over time using the cost and carbon intensity projections provided by the DECC/HM Treasury Green Book guidance on valuing energy use and greenhouse gas emissions.

The resulting figures were sense checked by stakeholders with experience of building energy efficiency interventions.

Case study sources

Green Book supplementary guidance: valuation of energy use and greenhouse gas emissions for appraisal

Financial Calculations


Energy savings were normalised using the energy spend of the NHS trust from which the various data sources were taken. This gave an average saving of £60,000 annually per trust based on the gas and electricity costs in 2015. Values were extrapolated over time using costs from the Treasury Green Book guidance.


Average capital costs per NHS trust normalised by energy spend were taken as £700,000.

Carbon Calculations

Average carbon savings per trust were calculated using carbon intensity projections from the DECC/HM Treasury Green Book guidance. In 2015, the carbon savings derived from the expected kWh savings were 500 tCO2 per annum for NHS Trusts.


The costs and savings detailed above represent those in addition to the installation of a Combined Heat and Power (CHP) system, rather than the outright installation of a district heating system.