That’s the greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials (e.g., concrete, foam insulation and steel).
Project coordinator Natalie Douglas is heading a low-carbon homes pilot project funded by FortisBC as part of the implementation of Nelson’s climate plan Nelson Next. It’s the first such work by a small city in Canada.
The goal, she told council at its Sept. 28 meeting, is to provide information and engage people in the building community on how Nelson and Castlegar can assist builders and homeowners who wish to reduce the embodied carbon in new buildings. The pilot project, which started earlier this year and runs until December, will not include any regulatory changes imposed on builders.
Douglas is supported in the project by City of Nelson building inspector Sam Ellison.
The first step has been to calculate the amount of embodied carbon in a typical house in Nelson and Castlegar. Douglas and her team analyzed 35 new houses in Nelson and Castlegar over the past few months by entering building data into a specialized tool developed by the group Builders for Climate Action in Ontario.
Much of the data collection and analysis work was done by Michele Deluca, a local energy advisor with 3 West Building Energy Consultants and a member of the pilot team.
The results of the pilot are summarized on a video presented by Chris Magwood of Builders for Climate Action, in which he lists the most carbon-intensive building materials in the 35 homes and their carbon footprints. He said the average carbon footprint of the materials in those homes was 26.4 tonnes per home.
Magwood said that extending those numbers to the 72 new homes built in Nelson and Castlegar in 2020 would amount to 1,900 tonnes of embodied CO2, the equivalent of driving 465 cars for one year or 900 tonnes of coal burned.
The study also produced a list of the materials with the highest carbon emissions in their manufacture averaged across the 35 buildings. These included various kinds of concrete, insulation and exterior cladding.
The results also include details on alternate types of concrete, insulation and cladding that have lower footprints.
This analysis is ground-breaking work, Douglas said.
“Nelson is one of the only communities in Canada that has gathered data on embodied carbon of new residential homes,” she said, adding that the City of Nelson will be presenting, along with the City of Vancouver to a group of B.C. municipalities on this topic in November.
In 2018, Vancouver adopted a plan to reduce embodied carbon in all new buildings by 40 per cent by 2030.
For the next step in the pilot project, to take place this fall, Douglas will be talking to builders, contractors, materials specialists, architects, and policy-makers in Nelson and Castlegar.
She will be looking for their advice on how to move forward with this information — how to create incentives for builders and homeowners to decrease their embodied carbon footprint.
Following those discussions, and before the new year, Douglas will develop educational materials for the West Kootenay builders and the public, including a guide to materials and their carbon footprints along with suggestions for alternative materials and recommendations on how to incentivize their use.
Building costs and regulations
At the Sept. 28 council meeting, Councillor Jesse Woodward asked if using low-emission materials will make construction more expensive.
Douglas said not necessarily.
“There is no correlation between low-carbon materials and high costs,” she said. “There are some that are lower, some the same, some higher.”
Mayor John Dooley echoed this concern, but then stated that, “At the end of the day, the consumer is going to drive demand, not the builder.”
Councillor Rik Logtenberg said this work would be valuable to all municipalities in the province and Nelson should get other municipalities to collaborate in funding a larger project.
Councillor Keith Page asked what sort of incentives or regulations will be created by council or the province.
“Will there be certain kinds of materials only allowed after a certain point? Will we be advocating for changes to B.C. building code? What is on the table, regarding options so total carbon costs will be as low as possible?”
Douglas said that discussion is already happening at the provincial level, and it may come up at council in the future, but this pilot project is simply to provide local data and education.