NET ZERO | DECARBONOMICS There are three steps to the Decarbonomics approach: benchmarking, roadmap and delivery Fabric-first approach 20 Reduction 0 Offsite 40 Fuel switching Offsite renewable 60 Solar power Onsite renewable 100 80 HVAC upgrades Residual LED lighting Heat decarbonisation Smart meters 120 Demand reduction The roadmap is intended to show a client how its buildings can get from their current carbon performance to the level that will enable them to reach their final performance destination. Data from benchmarking allows us to develop the roadmap to enable the client to make informed decisions, says MacLoughlin. Perhaps the most fundamental question that needs addressing at the outset is whether the estate and its make-up is right for a clients needs, both now and in the future. Do they have the right floor area where it is needed, because Covid has caused many organisations to review their estates in the light of new working practices, asks MacLoughlin. Having decided on the make-up of an estate, SNC-Lavalin then uses what MacLoughlin describes as a systems-based approach to assess potential interventions. Well look at the impact of interventions to a buildings fabric to reduce heating and cooling loads, whether thats through adding insulation, replacing windows, adding solar shading or improving airtightness, he explains. Once weve done that, well end up with a lower residual load that the HVAC systems then need to meet; then well look at decarbonising heat, perhaps by replacing gas and oil-fired boilers with air source heat pumps, which may also GPA net zero programme path to net zero Ops Optimisation Roadmap Quality of data can be an issue so well have to work with a client to determine the best way to understand the carbon performance of its buildings GHG emissions stage of Decarbonomics, SNC-Lavalin undertakes a site survey to assess the condition of the properties in the portfolio. In scoping the work for a particular project, our engineers and surveyors go to site to identify the opportunities to improve carbon performance, MacLoughlin explains. In its work for the GPA, for example, SNC-Lavalin had a building services engineer and a building surveyor visit various sites to undertake a detailed survey. The surveyors would already have the energy consumption data, so they would be looking at the condition and performance of the building fabric and M&E systems, to see what measures could be retrofitted, he says. The performance benchmark data for a portfolio of properties is presented to the client using a Decarbonomics dashboard and this is key to the next stage of Decarbonomics the roadmap. The GPA uses Decarbonomics in its net zero and life-cycle replacement programmes framework 32 March 2022 www.cibsejournal.com CIBSE March 22 pp30-33 Decarbonomics.indd 32 25/02/2022 18:30