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Optimizing our Energy Systems for Decarbonization

If our primary goal behind electrification is decarbonization - and it should be! -  then we  must ensure that as we electrify, we are using electricity for its highest decarbonization value.  Over the next two to three decades our electricity supply will not keep up with the demand for electrification.   That means we should ensure that, particularly for policy-driven electrification, that every marginal kWh of electricity is displacing the maximum amount of CO2

Public policy makers, regulators and utilities will have to come together to determine which electrification policies will have the most efficient (and scale) impact on decarbonization.  This is no small consideration.

All credible decarbonization pathways require very significant levels of electrification.  In fact, most observers estimate that the electric grid will need to deliver between two and three times more energy than it does today, and that would need to be in place within the next 25 years or so to meet 2050 net zero goals.  Without wholesale changes in how we design, consult, permit and finance these projects, this is simply not feasible.

British Columbia’s Site C hydro generating facility, for example, was first studied in the early 1980’s,  received approval in late 2014 and will start delivering electricity to the grid in 2025.  At 1100MW at peak - but slated for average capacity of about 600MW - it will deliver less than 10% of British Columbia’s electricity.  The province would need to build about ten(!) more projects of the scale of Site C over the next 20-25 years in order to double the grid, with additional parallel investments in transmission and distribution.  In fact, BC would need to have two more Site C scale generating plants online by 2030, just to meet the demand associated with the EV and heat pump policies currently in place.

Given these practical realities, we will have to be smart and nuanced about how we use each marginal kWh of electricity. 

In Ontario, a typical air source heat pump (with electric resistive backup) will mitigate a little over 1000kg of CO2 -- about 95g of CO2 for every kWh consumed. This is primarily because when the heat pump has to rely on electricity to supply supplemental heat on cold days, that electricity almost certainly comes from a marginal gas plant, generating significant emissions. That same heat pump, backed up by a high efficiency gas furnace, would mitigate nearly 3000kg of CO2 –  about 500g of CO2 for every kWh consumed – so that solution is about five times as efficient in reducing CO2 through electrification.   This means that policies – like the ones currently in place in Canada – that promote all electric heat pump options are actually supporting decarbonization solutions that are highly inefficient.  We SHOULD be promoting hybrid solutions, with gas backup, as a much more efficient way to use electricity to decarbonize.

By comparison, electric vehicles can mitigate as much as 800g of CO2/kWh, in a fairly clean grid (like Ontario’s) timed to consume during periods of low demand.   That means an EV is more than 8 times as efficient at using electricity for decarbonization as the all electric heat pump.  This is pretty good, and something our policy makers should be encouraging – even more than heat pumps!

We have to electrify almost everything to decarbonize our society – but smart policy means that we have to be pragmatic about how we think about ‘decarbonization efficiency’ as we think about electrifying society.

For the first 100+ years of our electricity grid, we really didn’t try to manage demand – we built the grid to support whatever was needed, as it was needed.  For the next 50 years, as we collectively address the existential crisis that is climate change, because of the scale of the change that is required, we will have to be more intentional about how we use our grid (and energy in general). 

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