The BEIS CHPQA Review in 2012 introduced a safeguard provision to ensure that renewable CHP schemes which initially fail to achieve a Quality Index of 100 but meet certain criteria can still be guaranteed a QI of a 100. A more generous X value will be re-calculated to allow the scheme to achieve a QI of 100 as described in Issues 5 and 6 of Guidance Note 44.
The re-calculated X value will be conducted on the scheme’s design data and will be used to calculate QI and QPO for the scheme at all operating conditions over its lifetime. There will be no subsequent re-calculation of the X value based on the scheme’s F4 operational data.
In order for a renewable CHP scheme which fails the QI at the design stage to be eligible for the safeguard provision above, it needs to meet the following criteria:
achieve minimum primary energy savings (PES) of 10% (0% for schemes < 1 MW electrical capacity)
achieve a minimum heat efficiency of 10% (based on gross calorific value, GCV), and
for schemes with electrical capacity > 25 MW, achieve an overall efficiency of at least 35% (GCV)
A renewable CHP scheme which fails the QI based on design conditions, can conduct the checks above to see whether it is eligible for the safeguard.
A spreadsheet tool has been developed to help CHPQA Responsible Persons (RPs) estimate the primary energy savings arising from their CHP scheme in comparison with the separate production of heat and power under expected or actual operation. The information required to perform the calculations (apart from the grid connection voltage in kV) can be found either on the CHPQA Certificate or on the CHPQA self-assessment forms.
Two PES calculation spreadsheets are available at the top of this page for use by RPs.
Which version of the PES calculation spreadsheet to use?
PES Version 1
Version 1 is based on historic EU reference efficiency values for the separate production of electricity and heat. This spreadsheet should be used for renewable CHP Schemes that received an F3 or an F4 CHPQA certificate prior to 1 January 2016 (but were not operational before 26 July 2012 and did not achieve financial close prior to this date).