Green Communities: Decarbonizing the Built Environment

Source: 

Pacific Institute for Climate Solutions 

Tue, 06/30/2020
A new Prince George-based study by the PICS Energy Efficiency in the Built Environment (EEBE) project may contribute to plans by that city and other similar communities to reduce greenhouse gas (GHG) emissions within the areas that residents live, work, commute and socialize. 
 
The study entitled Energy Efficiency in the Built Environment: Community Solutions; West Bowl Case Study Report is one of three neighbourhood scale case studies that simulate the climate impact of potential policy options governing growth management, active transport, and energy and emissions, within common types of communities found in British Columbia (BC): The community types being studied are high growth/high density/temperate climate (Vancouver), moderate growth/moderate density/temperate climate (Victoria) and low growth/low density/cool climate (Prince George).
 
Given that 55% of BC’s GHG emissions originate in the built environment where most people (86%) live, communities around the province are asking “which policies work best” for reducing those emissions. Prince George, for example, has set ambitious new short-and-long-term targets in its 2020 Climate Change Mitigation Plan released this spring, to reach an 80% GHG reduction by 2050.
 
With the support of city staff, researchers from the EEBE set out to find how policy options available to a city like Prince George affect GHG reductions and contribute to quality of life at the same time. Using spatially explicit models based on Prince George’s centrally located West Bowl neighbourhood, the researchers ran 9 experiments that simulated the effectiveness of combinations of proposed and contemplated growth management and active transportation policies, new building and retrofit standards, over thirty years of implementation (2020 – 2050).
 
Their findings?  Progress toward community energy and emissions reduction goals depend on appropriate combinations of policy options working together. In a less dense, slow growth community like Prince George, new energy efficient builds and higher density are necessary and important, but would contribute less (from a GHG reductions perspective) than deep retrofits of existing building stock coupled with expanded no-carbon travel options such as cycling paths. Dwelling density for example, was projected to increase modestly from the current almost 10 dwellings/hectare to 12 dwellings/hectare, by 2050.
 
To put some numbers on it; deep retrofits (to a high-performance standard) to existing buildings plus the implementation of BC Energy Step Code on all new buildings contributed to 37% reductions in annual building energy use per resident and 51% reductions in annual building emissions per resident – a sizeable step towards meeting community GHG reduction targets.
 
But what about the travel emissions that occur within the built environment? Small low-density cities such as Prince George are more significantly impacted by travel-related emissions (notably private automobile trips), with 38% of community emissions attributable to buildings and 52% to transport. What can help shift trips from private vehicles to transit, cycling or walking? Access and safety are two factors. The researchers found that by adding east-west and north-south designated cycling paths, the percentage of residents within 400 metres of cycling infrastructure increased from 69% to 93%.
 
The research team urges BC communities to consider combinations of building sector energy efficiency measures with complementary land-use and mobility policy initiatives to meet their emissions reduction targets. For full details on the modelling approaches used, and the scenarios that were tested, click here to read the West Bowl case study.
 
Pending is a forthcoming report from the EEBE project that will compare policy options in the three Vancouver, Victoria and Prince George case studies together.