Influence of material choice, renovation rate, and electricity grid to achieve a Paris Agreement-compatible building stock: A Portuguese case study

The thermal retrofit of buildings plays a key role to limit global warming. However, the spatial and temporal dynamics of urban-scale renovation are not well understood. This paper proposes a new methodology that is based on a bottom-up building stock model. It links dynamic Material Flow Analysis with dynamic Life Cycle Assessment to include the temporal dynamics of emissions and renovation activity, and the spatial dynamics of the building stock. Alternative renovation scenarios for a Lisbon neighborhood are analyzed over the next 100 years. Thee scenarios include renovation rates, electricity grid transformation and material choice: Conventional renovation systems are compared to bio-based systems (using cork, wood and straw). A need-based prioritization of poorly insulated buildings is suggested and the effect of different energy grid transitions analyzed. The results show that bio-based systems, especially made with fast-rotation biomass, are beneficial regarding radiative forcing. The straw- and wood-based system (“TES”), combined with an increased renovation rate, result in a cumulative radiative forcing of −45.4 * 10⁻⁸ kW/m² for embodied impacts in 2050, compared to 3.5* 10⁻⁸ kW/m² with a conventional system and a business-as-usual renovation rate. A fast and radical transition of the energy grid is crucial to meet the carbon budget to limit global warming to 2 °C.