Mapping and Modelling Energy, Carbon and Costs in the Residential Sector in the City of Prince George
From 2009 to 2012 Natural Resources Canada’s (NRCan) CanmetENERGY and Vive le Monde Mapping developed the Spatial Community Energy Carbon and Cost Characterization (SCEC3) Model for the City of Prince George. The purpose of the research was to explore the usefulness of map-based approaches for measuring and modelling energy, GHG emissions and costs in communities.
The SCEC3 model enables the estimation of energy, emissions and costs for Prince George’s residential housing stock. Future scenarios can be developed at the neighbourhood and community scales to assess energy, GHG emission and cost implications of the type and location of new housing, energy efficiency retrofits to existing housing, integration of solar hot water and solar photovoltaic technologies, district energy connections.
The SCEC3 model is innovative in its use of building data from BC Assessment and ecoENERGY audit records from NRCan. It takes an integrated community energy modelling and mapping approach, leveraging the power of software including HOT2000 and ArcGIS. To ensure it is useful for the City of Prince George, the model has been delivered in both Excel Dashboard and ArcGIS Application formats.
In the 2011-2012 timeframe, researchers designed 27 scenarios by making assumptions about future approaches to type, location and rate of new construction, retrofits to existing dwellings and integration of renewable energy technologies. These scenarios were run using the Excel Dashboard version of the SCEC3 model. Based on the City’s Official Community Plan (OCP) Growth Management Plan, four scenarios were then selected for analysis using the more precise SCEC3 model ArcGIS Application: the Business As Usual (BAU) reference scenario and three alternate futures called Standard Suburban, Neighbourhood Centres and Downtown Infill.
SCEC3 model development began in support of the Smart Growth on the Ground initiative in 2009. At that time a Foundation Research Bulletin was developed and outputs from the model supported community-members in selecting an energy efficiency target for new buildings constructed in the downtown.
The SCEC3 model was further refined in 2010 during the development of the city’s Integrated Community Sustainability Plan (myPG). The SCEC3 model contributed baseline mapping data to the effort. Future energy and emissions scenarios for the housing stock were developed and are described in a Case Study.
The SCEC3 model contributed to the City of Prince George being awarded the 2010 Community Energy and Climate Action Award. The model was then used to demonstrate energy savings from both predetermined and preferrred scenarios in Prince George's Community Energy Design Charrette. Maps showing energy efficiency scenarios for housing in the City are included in Section 6.5 of the Official Community Plan Bylaw No. 8383, 2011.
In 2011, the research concepts in the SCEC3 model were transferred to the Tract and Neighbourhood Data Modelling (TaNDM) project. TaNDM is a research initiative of the Province of British Columbia to improve the structure and completeness of the Community Energy and Emissions Inventories (CEEI). An improved method for CEEI reports has been developed as a pilot project, which includes a Standard Building Information Report from BC Assessment.
The methods developed in the SCEC3 project are also being shared with the BC Community Energy and Emissions Modelling Collaborative, the University of Manitoba, the Canadian Urban Institute and Horizon Electric Utility Corporation in the province of Ontario. Community energy and emissions planning efforts in the city of Prince George, including those associated with the SCEC3 model, are also documented in contribution to the International Energy Association’s Annex 51 on Energy Efficient Communities.
Results suggest that long-term cost savings could motivate the City and Prince George residents to work together to conserve energy and reduce GHG emissions in the housing stock. In contrast to the 2040 Business As Usual scenario, the three alternate future energy scenarios could potentially yield between $67.4 million and $97.4 million in cumulative cost savings for Prince George residents by 2040, after capital costs for energy upgrades have been repaid.
The three alternate future energy scenarios could see between 5.2 % and 8.3 % less total energy consumption and between 6.5 % and 8.7 % fewer greenhouse gas emissions by 2040 than the 2040 BAU scenario.
First established through the Partners for Climate Protection program and adopted into the Official Community Plan, Prince George’s community-wide target is a 2 % reduction in GHG emissions from 2002 levels by 2012. The SCEC3 model results show that only by pursuing the Downtown Infill scenario (which took the most intensive approach to retrofits to existing dwellings, renewable energy technology integration and energy efficient new construction) can the residential sector potentially achieve this target. However the date by which the GHG emissions reduction target may be achieved is too far into the future: the Downtown Infill scenario anticipates that the residential sector will only achieve a 2.3% reduction in GHG emissions from 2002 SCEC3 model levels by 2040.
What do the cost savings look like for the average resident of Prince George?
Retrofits to existing dwellings - For the most common single family dwelling in the city built between 1943 and 1977 (that make up 44% of the Prince George housing stock), an effective combined retrofit involves upgrading the furnace, closing the chimney and installing an instantaneous hot water heater. This combination has an estimated capital cost of $7,475 and has a simple payback of 8 years; it has the potential to save an estimated $6,600 after 13 years and $27,000 after 28 years in cumulative operating energy costs, after capital costs have been repaid. This combination also achieves a 31% reduction in energy use and a 42% reduction in GHG emissions relative to energy performance and GHG emissions prior to the retrofits.
Renewable energy technologies - A 60 tube solar domestic hot water system for a single family dwelling will save a homeowner $5,300 over 27 years versus $500 saved over the same time frame by a 30-tube system. The 60 tube system has an estimated capital cost of $8,000, an incremental cost of $1,750 over the system half of its size. The solar domestic hot water system that was modelled for the single family dwelling modelled above was also found to achieve an 86% reduction in natural gas use and GHG emissions associated with hot water use.
Importantly, this research also identified that not all existing homes in Prince George are well suited to harness solar energy due to the slope and orientation of their roofs. In fact, only 24 % of existing dwellings have roof-tops suitable for solar domestic hot water systems. A no-cost check that can be done by home-buyers interested in installing a solar domestic hot water hot water system is to ensure there is a roof area at least 6m2 in size facing south or south-west. For those looking to build a new home with solar ready features, design guidelines are available here.
Approaches to energy efficiency new construction - The strategy laid out in the Smart Growth Downtown Prince George Concept Plan placed an emphasis on higher density apartment units in the downtown. This and, focusing growth of row houses and high efficiency SFDs, if possible built to EnerGuide for Houses 86, in OCP growth priority areas saves residents twice: once through lower housing energy use and GHG emissions and a second time by supporting more sustainable transportation options. Another important co-benefit of providing smaller apartments and town houses is that these types of units can provide affordable housing, often required by students, young families and senior citizens.
The Practical Challenge of High Up-Front Capital Costs
Results of the SCEC3 model speak to the long-term cost savings opportunity but also highlight the short term challenge of high up-front capital costs of potential technical solutions. With the Integrated Community Sustainability Plan (myPG) and OCP completed, the City of Prince George has the enabling policy framework in place. The next challenge, beyond the scope of this research, is to identify creative financial solutions to make implementation accessible and affordable for everyone.
Financial solutions and communication efforts such as cross-promotion of information and incentive programs from utilities and other levels of government can support the residents of Prince George to plant the trees of energy conservation and renewable energy technologies that will one day grow into a forest of cost savings.
A Report of the SCEC3 model methodology and results is now available. For a complete list of resources relating to the model please see SCEC3 Model Publications and Presentations.
The City of Prince George gratefully acknowledges the technical expertise of CanmetENERGY and Vive le Monde Mapping as well as financial support provided by the Government of Canada through the Program of Energy Research and Development and the ecoENERGY Innovation Initiative.