Holdfast Training Services Trial Blog

As 1 of 12 benefits forming the business case for the current project I’m working on it was identified that the installation of more efficient primary plant (CHP and boilers) along with more sophisticated and energy efficient control systems, pipework insulation, wireless thermostatic radiator valves (TRV) etc. would reduce the carbon emissions of the building.

Based on the improvements mentioned above and gas and electric meter readings of the building it was estimated from the antiquated 2017 SAP carbon intensities (0.218 kgCO2/kWh for gas and 0.399 kgCO2/kWh for electricity) that a saving of 554 tonnes of carbon per annum would be achieved, this figure is enshrined in the business case and needs to be met.

Flaws…

The project identified that the building was insufficiently heated and has upgraded both the capacity of the primary plant and the pipe sizes to accomodate faster mass flow rates and therefore an adequate delivery of heat as per the only equation I remember from phase 1, Q=mdot*Cp*DeltaT… joking of course.

More heat at a better efficiency = net carbon emission increase or decrease?
The metering strategy within the building is crude with little sub-metering, coupled with the fact that the occupancy patterns and building use are highly variable increases the difficulty with assessing in any detail the realisation of the target. It was also found that the lack of insulation on the pipework was actually relied upon in some areas (Like underfloor heating) to heat the bulding fabric. Therefore by introducing pipework insulation you’re reducing the heat losses in one place (the pipe) which increases the heat demand in other places (the emitters/radiators) to compensate for the removal of the indirect heating effect. Maybe there is a net reduction in consumption from the pipework insulation, no detail exists yet.

When the target was set there was no methodology for how to track and measure its achievement, no appreciation for the diffculties involved in being able to state, with a high degree of surety, this target has been met. It is assumed that the blanket energy meter readings will be looked at when the project is finished and the hope is that they’ve reduced by 554 tonnes of carbon…

Mission creep has led to enhancements and improvements that compromise the carbon target. Design ommissions such as the removal of wireless TRVs and large scale PV arrays just increase the burden for whatever solution (Likely a closed loop heat pump) is decided upon to address the delta in the carbon target.

Was the target SMART. Specific? Yes, Measurable? Yes but with sophisticated sub-metering and an accurate baseline with extensive data to start from. Achievable? Mission creep with a lack of cohesion across the programme may have resulted in net carbon emission increase, the data isn’t there yet.

White lies? Lets say your overall carbon emissions increased from 100 tonnes to 200 tonnes, but the plant you are now using is 93% efficient whereas before it was 75%. The argument could be made that as a direct result of having higher efficiency plant, the saving you have realised over the original plant is 18 tonnes of carbon, irrespective of the net carbon emission increase. The original wording in the business case was ‘reduce emissions by 554 carbon tonnes’ not ‘achieve a net carbon emission reduction of 554 tonnes’.

Whilst I see the importance for Bottom Line up Front business cases, in this situation the lack of detail with no technical justification completely discredit the benefit and the pressing environmental need for reduced ‘NET’ carbon emissions.

Food for thought.