Ontario is one of the few places where the grid is getting dirtier

Toronto and Canada are trying hard to electrify heating.¹ I’m told that starting around 2025 it’ll be pretty hard to build a new condo that uses gas heating, and many projects today are putting in ground source heat pumps from the jump. But all that new electricity demand won’t save us much emissions if the marginal producer of energy is natural gas! We all know that a heat pump running on natural gas is better than burning the gas, but it sure can be an expensive solution for not much impact. Electrification only makes sense if you’re decarbonizing the grid too. 

So I’m a bit disappointed to see that Ontario is one of the few places in the world where the carbon intensity of the grid (measured in gCO2eq/kWh) has been getting worse for three years straight. As far as I know, Ontario is the only region where carbon intensity has gone up so much (on a relative basis). Even Germany, notorious for closing all of its nuclear plants, has managed to keep emissions on a (slight) downward trajectory. All of this data is from the Electricity Maps web app, and I’m normalizing to 2018 (you’ll see why in a minute).

Why is this? Well, there’s something in here for everyone. But the main reason seems to be that Ontario is trading nuclear power for natural gas. Ontario gets most of its power from nuclear power plants (and so has very low absolute carbon intensity, see below), but nuclear production has fallen from 90 TWh in 2019 to 79 TWh in 2023. Renewables have not increased meaningfully,² so natural gas plants (like the one pictured above) have doubled production: going from 10 TWh in 2019 to 20 TWh in 2023, adding an extra 5M tonnes of CO2 emissions in 2023.

The good news is that Ontario still has pretty clean electricity. If you drop my somewhat sneaky relative basis comparison, Ontario is doing okay. Still though, if you compare to France, who also get most of their power from nuclear, it’s pretty disappointing. France doesn’t really have the option to use natural gas the way Ontario does, but it shows a path that Ontario could have chosen. This is a longer subject, but I think that Ontario has great wind and solar resource that it should absolutely be leveraging.

1. Toronto and Canada both have grants for single family homes, and the city has a program for rental apartments or shared areas in condominiums. But there is no program for condominiums over three stories that have individual HVAC systems for each unit (which happens to be my family’s situation). ↩︎
2. Ontario has significant hydro and wind, but negligible solar and biomass. Ontario Premier Doug Ford famously had to pay $231M in fees to cancel some 750 renewable energy contracts, but is now looking to procure 2 GW of wind, solar, and hydro. ↩︎