News broke this week that “the Ontario government plans to make the majority of the province’s buildings emissions-free by 2050 as part of a dramatic plan to meet its climate change goals.”

The current version of the Ontario Building Code (OBC) has an energy performance requirement for buildings that requires the proposed building design to have lower modelled annual energy consumption than a reference code building. Two other less well known requirements of the Code are that the proposed design must also have lower peak electrical demand and lower annual carbon emissions.

For the purposes of calculating carbon emissions, the OBC provides carbon intensity factors of 400 grams per kWh for grid-delivered electricity (approximately equal to the intensity of electricity generated by natural gas) and 191 grams per equivalent kWh for natural gas burned on site. This means that the OBC considers grid-delivered electricity to have a higher carbon intensity than any fossil-fuel based energy source delivered to a building, a structure that strongly favours energy saving strategies which reduce electricity consumption over those which reduce natural gas consumption.

However, grid-delivered electricity in Ontario currently has a much lower annual average carbon intensity of 77 g/kWh. This low carbon intensity is due to the elimination of coal power and the use of nuclear and hydro power to generate most of Ontario’s electricity. With more renewable power coming on line every year — I just checked Gridwatch on a weekday morning in April and wind was supplying more electricity (11%) than natural gas (5%) — it’s more clear than ever that if the Ontario government wants to reduce carbon emissions in buildings, it will have to encourage the development of low-carbon space heating strategies that do not rely on natural gas. If the carbon intensity factors of the OBC were to change so that electricity had a lower carbon intensity than natural gas, this would represent a dramatic swing to a new structure that favours energy saving strategies that reduce natural gas consumption over those that reduce electricity consumption.

For example, in a building heated by natural gas, reducing lighting power will save energy on electricity but will increase energy on natural gas. Although total energy will be saved on balance, the reduction in waste heat from the lights will require the heating system to use more natural gas to keep the building at the same temperature. This energy-saving strategy would lower carbon emissions for electricity with a carbon intensity factor of 400 g/kWh, but it would increase carbon emissions with a carbon intensity factor of 77 g/kWh.

Regardless of what happens with the OBC, the path to reducing carbon emissions in Ontario leads away from using natural gas for space heating. Arborus has been researching low carbon space heating strategies for the Ontario building market, and will soon publish a white paper on the subject to be presented at the SBE 2016 Conference in Toronto on September 19th and 20th.