Which combination of policy measures are most appropriate for reducing urban emissions? New peer-reviewed research shows how economic, technology and urban building energy models can be combined and used to evaluate policy efficacy.

Until now, uncertainties of economic and market-driven factors in urban building energy models (UBEM) have been a challenge for building energy modellers. The spatial impact of energy and emissions policies in urban environments is often hard to determine. UBEMs often fail to recognise the financial and social influences over new buildings and/ or retrofitting existing building stocks. In INTEGRATION OF AN ENERGY-ECONOMY MODEL WITH AN URBAN ENERGY MODEL, Lu et al. present a new approach for integrating these different types of model. Specifically, the authors integrate outputs from a spatial economic model with a spatially explicit community-level UBEM. This is a major contribution in the development of an integrated modelling approach, but also in quantifying the co-benefits of multi-scale effects of energy and emission reduction policies.

Lu et al. adopt a 'sandbox' approach to simulate urban form and building retrofit policies, working at a neighbourhood scale. The sandbox represents a particular urban form, including population density, street pattern, block size and land-use proportions, all derived from a real neighbourhood. This allows for an increasingly realistic representation of the integrated processes that influence energy-usage and emissions output, including fuel choice, building design, mechanical systems, urban form and behaviour.

With this combination, the researchers have been able to model the evolution of a neighbourhood's individual buildings (HVAC system and the building shell) over time. This provides a much higher level of granularity than many existing efforts to understand how building stock changes over time in response to different policy strategies. The interaction between building technology policies and different urban growth-management strategies can be better understood and harnessed. Policy makers are afforded extremely valuable and detailed insights into the impact of energy policies at an individual building-level, prior to their implementation. Insights arising from this combined model will assist practitioners involved in both city planning and energy management.

A case study applies the model to the Sunset region of Vancouver, Canada. The case study explored three urban-form policy experiments: dispersed, commercial corridor, and transportation-oriented development (TOD). The analysis illustrates the combined results of a technology policy regulating a shift towards electrification and a spatial urban form densification policy. The authors identify specific growth-management strategies that can be more effective for reducing emissions than when integrated with other urban form strategies.

Policies focused on energy and emissions standards for new buildings will be relatively more effective in areas with a growth-management strategy that necessitates the redevelopment of many existing buildings. This demonstrates a useful approach for understanding exactly which policy instruments, such as densification, higher building energy standards, and fuel switching, will bring the most emissions reductions.

Funding

The research was funded by Pacific Institute for Climate Solutions (PICS).  Additional funding from Environmental Systems Research Institute (ESRI) Canada and the Natural Sciences and Engineering Research Council (NSERC) supported tool development and related research.

Reference

Lu, Y., Scott, A., Kim, J. C., Curi, C. B., McCarty, J., Pardy, A., Rysanek, A., Girling, C & Kellett, R. (2021). Integration of an energy-economy model with an urban energy model. Buildings and Cities, 2(1), 114-133. DOI: https://doi.org/10.5334/bc.71