Looking at this morning’s Ontario electric grid numbers, you might get the impression that the morning energy peak in this province was around 18,000 megawatts, and that that peak will, if today is similar to yesterday (i.e., a hot and humid mid-week day across most of the high-population areas in Ontario) gradually increase through the day till it reaches the real peak of roughly 22,000 MW. That impression would be wildly wrong.
This is what the real Ontario energy peak looks like. Vehicles in Ontario generate roughly 25,000 megawatt-hours of energy per hour during rush hour, and dump roughly 6,000 tons of carbon dioxide into the air. If we replaced nuclear electricity generation with gas-fired, then the generators that feed Ontario’s electric grid would dump a similar amount on top of that.
The Ontario energy peak this morning was not anywhere near 18,000 megawatts. It was at least twice that, and I’m not even counting the energy we get from our morning ingestion of pharmacological hydrocarbons (caffeine). My own estimate is that it was in the neighbourhood of at least 40,000 to 43,000 megawatts; possibly much more. That does include the roughly 18,000 MW of electricity, but it also includes another huge, and hugely overlooked, energy category: vehicle transportation. Vehicle transportation, I estimate, used 22,000 to 25,000 MWh of additional energy between 7 a.m. and 8 a.m. this morning.
I base this estimate on two things. First, Statistics Canada (CANSIM, table 405-0002) reports net gasoline sales of 16.4 billion liters in Ontario in 2013. I strongly doubt that many of those litres spent the year in storage. They were stored, but in vehicle fuel tanks, whereupon they were shortly after burned in order to provide motive power. Convert 16.4 billion litres to energy (the whole reason for buying them), and you get 154.2 billion kilowatt-hours.
The second thing on which I base my estimate of an additional ~25,000 MWh of energy is my personal observation that downtown streets in Ottawa, where I live, are typically clogged with bumper-to-bumper car traffic from seven a.m. to nine. Ninety-nine-point-nine percent of those cars are powered exclusively with an internal combustion engine using gasoline as fuel. Every single one of those burns gasoline, at the rate of at least one litre per hour but more often at two to three liters per hour, during its journey. Each litre contains roughly 9.4 kilowatt-hours of chemical energy.
On this basis, I figure there are, on any given morning rush hour, around 1.3 million cars on Ontario roads. If anyone can corroborate this figure, please let me know.
The carbon content (CIPK) of each of those additional ~43,000 MWh of energy was 245 grams.
As you can see, the CIPK of the energy from the electricity grid is much much lower than that.
Here’s a question. If we wanted to reduce the CO2 from vehicles, how should we go about it? By conserving fuel? Or by using cleaner energy to drive our cars?
The CPIK for the ICEV needs to be divided by the drivetrain efficiency to get the TTW-equivalent CPIK. That will be several times the 245 gCO2/kWh figure.
The either/or is a false dichotomy; both will work and some schemes leverage substitution to also increase efficiency. The ultimate solution is BEVs charged with carbon-free power from whatever source, but in the short term “mild PHEVs” with a handful of kWh of storage in high power-density batteries can both substitute electricity for liquid fuels and get much greater efficiency from the fuel they do use.
I thought about that, and elected to go with taking the CIPK of the whole gasoline kWh, not just the part of it that actually moves the car. Of course, a kWh used by the electric part of the hybrid drivetrain is far more efficient, and comes with far lower carbon-per-kilometer than the gasoline engine.
And of course plug-in hybrid gasoline-electric is absolutely the near-term solution to vehicle emissions — the technology is available right now; just needs to get more affordable. Most current ones can handle typical city trips (< 20 km) on pure electric.
Even 20 km is in full-PHEV territory. The near term is going to use what can be shoehorned into existing chassis forms with minimal impact. I like this aluminum-ion battery, assuming it can be built to automotive specs at a reasonable cost, because the cycle life is great and the power-to-weight ratio (3 kW/kg) is amazing, even though the energy density (50 Wh/kg) is blah. 120 kW out of 40 kg of battery is huge. The 2 kWh of storage won’t get you very far (perhaps 8-12 km) but being able to downsize the engine radically and optimize it for pure thermal efficiency would pay off massively. You might want to retain the FWD mechanical transmission for cruising efficiency, but you could get AWD using independent motors on the rear wheels with no mechanical connection to the engine.
At 3 kW/kg, 40 kg of cells packs 120 kW of peak power. That’s 20% more than my Passat TDI had, and while it was no sports car it was not slow. Being able to absorb 120 kW from regenerative braking would slow a 1500 kg vehicle from 100 kph to 20 kph in less than 5 seconds without using friction brakes. Such a car would need rust-free brake surfaces because otherwise they’d almost never get the corrosion polished off and they’d be at risk of locking up.