Mitigating building emissions

Globally, building construction and use is responsible for about 33% of energy consumption and almost 15% of direct greenhouse gas emissions.[1] In Canada, the energy use of buildings in itself accounts for 18% of national emissions. This includes space and water heating, electricity use for cooling, lighting and appliances.[2] In BC, buildings account for about 12% of provincial greenhouse gas emissions.[3] Therefore, reducing the greenhouse gas emissions from the construction and use of buildings is a key component of meeting emissions reductions targets.

BC has introduced the CleanBC Roadmap to 2030. One of the key pillars of the roadmap is “clean and sustainable communities.” Adopting the Energy Step Code is another approach that local governments can use to reduce emissions. There are many other tools, approaches, and funding opportunities that local governments can use to reduce building-related emissions throughout their lifecycle.

Local governments have direct influence in addressing corporate emissions from buildings, namely through ensuring energy efficiency in new civic buildings and retrofitting older buildings. Considerations include building materials, heating/ventilation systems, energy efficiency, energy sources, as well as location and siting. Local governments also have an indirect influence on community-wide emissions reductions through land use regulation, adopting the Energy Step Code, and incentivizing retrofits of the private building stock.

A corporate lens on buildings

Buildings owned and operated by local governments are an area of focus in corporate emissions reduction.

Low carbon planning, design, and contruction

Encouraging low-carbon construction reduces energy consumption and emissions by orienting and designing the building for efficiency and effectiveness, selecting low-carbon building materials and materials that are available locally, which reduces emissions from transportation.

A low cost way to reduce building emissions is to consider the siting and orientation of the building elements carefully. To reduce heat gain, orient windows towards the north and install external shades on south-facing windows. To increase ventilation, include operable windows at opposite ends of a space. Higher windows can pull warm air out of a space, and a thermal chimney can create a ventilation effect by pulling warm air out of the top of a building. To reduce heat loss, aim for more compact buildings with a lower ratio of envelope to interior space. Buildings that are inset into the ground take advantage of the constant temperature of the earth and can reduce heating and cooling requirements. All of these design strategies take advantage of passive heating and cooling principles rather than relying on mechanical systems to condition a space.

Materials and building technologies influence emissions and energy consumed in building construction. The total emissions from all building materials and products and the energy expended during construction accounts for approximately 20% of the building sector’s carbon emissions. When considered together with operating buildings, the built environment generates approximately 40% of annual global emissions.[3] Reducing embodied carbon (the emissions associated with the lifecycle of a building, from manufacturing to decommissioning) in the buildings sector plays a role in reducing emissions globally. 

There are many creative and well-tested alternative materials that can reduce the embodied carbon of buildings. For example, by using building materials that are available locally emissions from transportation can be reduced. Low-carbon building materials, such as BC wood and Portland-limestone cement (which has 10% less embodied carbon that regular Portland cement), require less energy to manufacture than other common building materials such as steel and aluminum. Additional bio-composite and low-carbon building materials include rammed earth, straw bale, and hempcrete.

Embodied carbon includes end of life, extract raw materials, transport raw materials, manufacturing, transport to site, build. Operate is outside the model.
Embodied carbon includes a building’s lifecycle steps [4]

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An olympic achievement

Richmond Oval

In 2009, the Province of BC passed legislation to encourage the use of pine beetle affected wood as a building material for new publicly funded buildings. This aims to reduce carbon emissions associated with decomposition or burning of wood from trees damaged by pine beetle. Wood from trees damaged by pine beetle has been used in building construction material across BC including, for example, the Richmond Olympic Oval.

Working toward net-zero buildings

Net-zero buildings are those that do not directly contribute to greenhouse gas emissions over their lifecycle. In order to achieve net-zero buildings, several factors must be taken into account:

  • Extraction, manufacturing, and transport of materials to the building site as well as their assembly onsite
  • Energy used during the operations of the buildings, including space heating/cooling, water heating, appliances, lighting, energy consuming devices and electric vehicle charging
  • Emissions from the disposal or decomposition of the materials after the building’s lifecycle is complete.

This comprehensive accounting of the emissions from a building is complicated and often the data is not available. As a result, net-zero buildings are generally achieving net-zero objectives wherever possible rather than having met this high bar throughout all phases of their lifecycle. However, each phase is important and when all of these phases are taken into account, buildings have a significant impact on community emissions inventories. For example District of North Vancouver estimates that residential, industrial, commercial and institutional buildings combined account for 41% of the sources of all carbon emissions of the municipality.

The concept of net-zero or zero carbon buildings is helpful in framing the role of buildings in mitigating emissions and playing a role in carbon neutrality. While net-zero energy/zero carbon green buildings may reduce energy consumption and carbon emissions, the terms encapsulate several performance categories in terms of emissions reductions. For example, a newly built facility may be “net-zero ready” such that it is designed to accommodate renewable energy generation such as solar arrays. However, the facility may be heated using gas or consume electricity from a non-renewable grid. In contrast, zero carbon, grid interactive buildings use no non-renewable energy sources for heating/cooling and do not place high demand on green electricity grids by managing demand, load, and on-site energy storage.

Summary of net-zero energy ready to zero carbon continuum[5]

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A community-wide lens on buildings

Siting municipal facilities

  • Beyond the direct emissions from the construction and use of buildings, there are indirect emissions that result from the location and site design. Decisions about where buildings are located, what mode of transportation they support, and their relationship with other places in the community can also make a difference in emissions reductions.

This may involve considering:

  • how the public and employees will access the facility (transportation mode)
  • how the facility is integrated into the adjacent community (public realm, landscaping, and land use mix)

The site design contributes to the convenience of various modes of building access and also sends signals about how a building is to be accessed. Therefore, buildings should emphasize the preferred modes of access where feasible. Examples include:

  • Minimizing parking and placing parking spaces to the rear of the building so the building addresses the street frontage, where appropriate
  • Charging for public parking whenever possible
  • Providing preferred parking for carshares, small vehicles or low/zero- emissions vehicles
  • Providing electric vehicle chargers
  • Providing adequate and safe parking for bicycles of all types and sizes
  • Providing safe and paved sidewalks or pathways between the building access and the periphery of the site, such as sidewalks along neighbouring streets
  • Connecting the building entrance to bus stops or other transit options

When selecting the building site, prioritize one that:

  • Is close to sidewalks or access points used by pedestrians, with windows facing the public realm that connect the building to the community.
  • Can share parking and other amenities with complementary uses nearby
  • Is close to transit routes/stops and active transportation routes
  • Integrates a range of land uses and/or is in an area with higher density such as a downtown or community node. This may include co-location of uses such as a library below residential and office, or a recreation centre that includes retail uses
  • Integrates concepts of social equity in locating facilities so they can be more easily accessed including by underserved groups
  • Integrates concepts of adaptation in location selection and site design. This may include avoiding hazard areas, avoiding environmentally sensitive areas, using green infrastructure stormwater features, and using drought resistant and native species in the landscaping plan

A community hub

The Greater Victoria Public Library opened its sxʷeŋxʷəŋ təŋəxʷ James Bay branch in 2018. At the corner of Menzies and Superior Streets in Victoria, the branch is a prominent part of a mixed-use phased development that features residential, office employment, retail grocery, and retail café land uses. The development site, located near the provincial legislature and a transit exchange, incorporates a pedestrian-focused public realm and cycling facility improvements.

Influencing community-wide building energy efficiency

While local governments can directly reduce emissions from their own corporate buildings, they only have an indirect ability to reduce emissions from privately-owned buildings through their communities.

The BC Energy Step Code is an optional compliance path in the BC Building Code that local governments may use to incentivize or require a level of energy efficiency in new construction that goes above and beyond the requirements of the BC Building Code. Over 70 local governments reference the BC Energy Step Code in their building bylaws.

For example, the Bowen Island Municipality updated its building bylaw in 2019 to require that building permit applications under parts 3 (complex buildings) and 9 (houses and small buildings) of the BC Building Code meet step 1 (energy model at design stage). As of October 2020, parts 3 and 9 applications are required to meet step 3 (energy model at design stage as well as post-construction performance improvements).

Pathway to net-zero-ready construction in the BC Energy Step Code

The Better Buildings BC Program is a provincial incentive program that supports the design and construction of multi-unit residential, commercial, and institutional buildings that target the BC Energy Step Code or the Passive House standard. The program offers financial incentives for net-zero energy ready buildings.