commercial buildings stuck at GHG status quo

Commercial buildings stuck at GHG status quo

Monday, May 7, 2018

Commercial buildings aren’t making much contribution to Canada’s efforts to reduce greenhouse gas (GHG) emissions to 30 per cent below 2005 levels by 2030. The most recent National Inventory Report, filed with the United Nations in April, finds commercial buildings stuck at GHG status quo — registering the same output of 40 megatonnes (Mt) of carbon dioxide (CO2) equivalent in 2016 as in 2005. However, that is an improvement from the first half of this decade when annual emissions wavered from 41 to 42 Mt.

Nationally, Canada is making somewhat better progress as total GHG emissions dropped to 704 Mt of CO2e in 2016, representing a 28 Mt reduction from 11 years earlier. Arguably, too, growth cloaks some of the achievement thus far. Emissions fell from 22.7 tonnes per capita in 2005 to 19.4 tonnes in 2016. From a GDP perspective, the GHG intensity dropped from 0.49 Mt per $1 billion of GDP to 0.39 Mt per $1 billion of GDP in 2016. Nevertheless, Canada’s reduction commitment is volumetric and GHG levels will have to drop to roughly 510 Mt over the next 14 years to meet the target.

The second warmest winter in 70 years factors into residential GHG emissions for 2016. They dropped to 41 Mt CO2e — down from 45 Mt in 2015 and 47 Mt in 2014. Even so, heating accounts for the overwhelming share of residential emissions, with fully 39.3 Mt attributed to combustion of fossil fuels.

The emissions profile for the commercial building sector is more varied. Fossil fuel combustion produced 29.3 Mt of emissions with another 0.7 Mt from cogeneration. Processes involving halocarbons, sulphur hexafluoride and nitrogen trifluoride added another 5.6 Mt, while non-energy products and solvents produced from fossil fuels contributed 4.5 Mt.

Together, commercial and residential buildings are deemed responsible for 12 per cent of the total emissions in 2016. Of the seven economic sectors where GHGs are apportioned, oil and gas was the biggest emitter in 2016 at 183 Mt CO2e, followed closely by transportation with 173 Mt of CO2e. Those two sectors account for more than half of the year’s emissions. The remainder arose from: electricity (11 per cent); heavy industry (11 per cent); agriculture (10 per cent); and waste and others (6 per cent).

Although emissions related to electricity generation are categorized separately, Canada’s report to the UN draws a connection between the two sectors when it outlines how further GHG reductions may be achieved in the buildings sector. “Measures in the Pan-Canadian Framework that are expected to impact future trends in this sector include developing net-zero-energy-ready building codes that can be adopted by 2030 for new buildings; retrofitting existing buildings and providing businesses and consumers with information on energy performance; and improving the energy efficiency of appliances and equipment. The development of a clean fuel standard will also influence future trends in this sector,” it states.

The report’s breakdown of provincial electricity supply and resulting GHG output draws attention to Canadian regions where efforts to save energy will have a proportionally greater impact on emissions. Generation intensity, measuring grams of CO2e per kilowatt-hour (kWh) of electricity consumption, varies dramatically in Canada’s four most populous provinces.

In Quebec, where 99.5 per cent of the electric supply comes from hydroelectric and renewable generation, the generation intensity is 1.3 grams CO2e/kWh. Quebec’s greater reliance on electric heating similarly results in a lower GHG output relative to other provinces — 10.9 Mt in a province with about 8.2 million inhabitants versus 17.7 Mt in Alberta, which has roughly half that population.

In 2016, Alberta’s generation intensity was 760 grams CO2e/kWh, largely attributable to the coal-fired generating plants producing nearly 62 per cent of the province’s electricity supply. British Columbia’s energy intensity was 11.1 CO2e/kWh and Ontario’s was 36 CO2e/kWh.

Looking outside Canada, the U.S. GHG inventory report draws clearer connections between electricity generation and its end-users. It identifies the electric power sector as the source of 28 per cent of national GHG emissions in 2016, but then apportions that 1,809 Mt of CO2e among the three major sectors — commercial, residential and industrial — consuming power.

Nearly 664 Mt of commercial emissions and more than 684 Mt of residential emissions are attributed to “indirect fossil fuel combustion” related to electricity use. This, in turn, reflects the predominant sources of power generation, as nearly two-thirds of the U.S. power supply is coal or natural-gas fired. In contrast, less than 19 per cent of Canada’s power supply is fossil-fuel fired.

On the flipside, Canadian buildings proportionately emit far more GHGs from direct combustion. U.S. commercial building emitted 231.3 Mt of CO2e and residential buildings emitted 292.5 Mt of CO2e across a population approximately ten times greater than Canada’s. This reflects the Canadian climate and reliance on fossil-fuel fired heating.

Combined direct and indirect emissions from U.S. commercial and residential buildings appear to have dropped more notably from 2005 levels, with a 16 per cent reduction in the commercial sector and a 22 per cent reduction in the residential sector. However, commercial improvement is solely related to indirect emissions and the changing electricity supply. Direct emissions have risen by 4.3 Mt.

“Recently, a decrease in the carbon intensity of the mix of fuels consumed to generate electricity has occurred due to a decrease in coal consumption, increased natural gas consumption, and increased reliance on non-fossil generation sources,” the U.S. report observes. “While emissions from the electric power sector have decreased by approximately 0.1 per cent since 1990, the carbon intensity of the electric power sector, in terms of CO2 equivalent per QBtu (quadrillion British thermal units), input has significantly decreased — by 12 percent — during that same time frame.”

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