Towards net-zero futures: Modular Passivhaus design as a solution to meeting national carbon targets for new housing

Much of the world has an urgent need for housing yet simultaneously have set binding targets on reaching zero-carbon. The buildings sector is responsible for 31% of global CO2 emissions, 50% of which results from operational energy use in housing and 18% from embodied carbon emissions. Previous research has claimed that reducing both operational and embodied carbon to net zero is impossible with current building methods. In this paper, we introduce a new time-series based whole-life carbon analysis methodology for examining such problems globally. This combines operational and embodied modelling together with current and predicted grid carbon intensities. As a demonstration of the approach, a model for UK housing demand was created, predicting the carbon impact if a modular Passivhaus approach was used to meet the housing target of 300,000 homes per year. By 2050, this housing solution only consumes 90% of the total embodied and operational carbon budget allocated to new housing (545 of 604 MtCO2e). It is therefore concluded that with a modular approach, the housing target can be met whilst remaining within the carbon budget, suggesting that the approach has the potential to help solve housing need and the need to reach net zero rapidly and globally.
Practical Application
If the construction industry is to stay buoyant yet not undermine carbon targets it needs to move towards construction techniques that simultaneously reduce operational and embodied emissions. Although once upon a time sustainability was seen as a move in a direction, it is increasingly framed as a numeric target – zero. Hence the industry needs approaches that meet this target and accountancy methods that make this evident. This work demonstrates both.