Modelling decarbonisation pathways: from global pledges to buildings and cities

UBEM-SER: Role of sufficiency, efficiency and renewable in the decarbonization of commercial building stock at city scale
The transitional pathway for decarbonization of commercial building stock requires adequately managing the degree of complexity by providing a coordinated effort with the implementation of non-technological mitigation strategies, energy conservation measures and the use of renewable distributed energy resources (DERs). However, there exist significant challenges in facilitating coordination among different methodological characterizations of building stock interventions. These challenges hinder the ability to reveal the quantitative description of sufficiency, efficiency and renewable DERs in achieving a carbon-neutral building stock. To address this challenge, this paper presents a multi-model framework to integrate an urban building energy model (UBEM), that supports the consideration of energy conservation and socio-behavioural effects, with a physical-based approach of BIPV potential estimation to estimate energy demand and supply patterns of commercial building stock at the city scale. A scenario-based simulation procedure is constructed to explore the degree of variability of sufficiency and efficiency dimensions in decarbonization pathways as complementary levers rather than contrasting ones. The analysis of results reveals that: sufficiency provides an additional gain of 15 % to reduce the annual median value of energy use intensity (EUI); 60 % reduction in energy demand is observed with larger energy savings originating from efficiency measures accounting for 46 % reduction potential; and sufficiency supports wider decarbonization with reduction of peak load by 18 % and improvement of self-sufficiency (SS) by 20 % with longer duration of negative net load. Overall, this study provides a context-based perspective of energy conservation and socio-behavioural effects to energy modelers and policymakers for achieving broader decarbonization of commercial building stock at the city scale.

Promising climate progress from net-zero ambitions to the Paris Agreement goal
Isabela S. Tagomori (PBL), Fabio A. Diuana (Coppe), Luiz Bernardo Baptista (Coppe), Christoph Bertram (UMD), Ioannis Dafnomilis (PBL), Laurent Drouet (CMCC), Florian Fosse (JRC), Dimitris Fragkiadakis (E3M), Oliver Fricko (IIASA), Elena Hooijschuur (PBL), Gokul Iyer (UMD), Jarmo S. Kikstra (IIASA), Volker Krey (IIASA), Gunnar Luderer (PIK), Yang Ou (Peking University), Lara Aleluia Reis (CMCC), Oliver Richters (PIK), Pedro R. R. Rochedo (Khalifa University), Zoi Vrontisi (E3M), Matthias Weitzel (JRC), Matthew Zwerling (UMD), Bas van Ruijven (IIASA), Roberto Schaeffer (Coppe) & Detlef van Vuuren (PBL/UU)

Climate targets require strong commitments from countries to be achieved. Using a multi-model analysis, we show that current net-zero pledges bring the world closer to a well-below 2 °C pathway, but an emission gap remains. Increasing ambition will be crucial: expanding the global coverage of net-zero pledges and speeding up action increases consistency with the Paris Agreement (1.5–2.0 °C range in model mean). However, reaching the 1.5 °C goal without overshoot seems increasingly unlikely. While net-zero pledges help reduce carbon-intensive energy sources, domestic policies aligned with strong climate commitments are needed to reduce the reliance on fossil fuels and increase renewable energy capacity. Our scenarios show that emission reductions are driven by gains in energy efficiency, a strong phase-down of coal use and the electrification of sectors such as transport and heavy industry.

The climate policy modelling protocol - Climate policy representation in integrated assessment models
Model-based scenario analysis is often used to evaluate the impact of national climate policies on global greenhouse gas (GHG) emissions. ‘Current Policies’ scenarios are thus normative scenarios that attempt a realistic representation of projected emissions that include policies adopted and implemented by national governments. In this work we present the Climate Policy Modelling Protocol (CPMP), a comprehensive protocol to translate climate policies on a national level into inputs to integrated assessment models (IAMs). Furthermore, we apply the protocol to develop the ‘Current Policies’ scenario using the IMAGE model, and present relevant results. The protocol can be used to guide the implementation of climate policies in national and global models, highlighting the importance of policy selection and quantification in IAMs, and the development of climate policy scenarios that add to the literature on baseline scenarios used by e.g. the IPCC assessment reports and the UNEP Emissions Gap report.