Decarbonisation options should be measured in a consistent approach to enable benefits to be measured and compared. Refer to Appendix 2 for a detailed checklist on information/units of measurement that should be obtained as part of a decarbonisation options assessment.
A summary of key benefits and units of measurement are outlined in the table below:
Benefit | Measurement |
Energy Savings | kWh savings p/annum kWh/m2/year |
Carbon Savings | tCO2e savings p/annum |
Cost Savings | £ savings p/annum £ per LT CO2e |
As outlined in the table above, a useful way to measure the relative carbon savings of different decarbonisation options is in terms of £ / LT CO2e, which is determined from the estimated CAPEX of a decarbonisation project and the persistence factor for a given technology. This allows the relative cost/carbon 'benefit' to be assessed i.e. the most carbon savings for least CAPEX.
Furthermore, there is a range of additional Benefits and Outcomes that could be achieved from implementing decarbonisation options - these are outlined in further detail in sections 8.2 and 8.3. Whilst some of these benefits are more strategic, such as achievement of NZ Targets and ESG/CSR, there are others that have more direct direct/immediate benefits that can be measured - a summary of these and units of measure are outlined in the table below:
Benefit | Measurement |
Thermal Comfort | Operative design temperature Overheating |
Lighting Optimisation | Illuminance levels Glare control |
Improved Air Quality & Ventilation | Temperature Relative Humidity CO2 Total Volatile Organic Compounds Formaldehyde PM2.5 PM10 Ventilation rates |
Acoustic Comfort | Acoustic standards specific to building type |
It is prudent to compare direct benefits (energy/carbon/cost savings) with indirect benefits (asset level benefits) to effectively evaluate decarbonisation options and inform the overall risk/commercial assessment.