Quote:
Originally Posted by Fuzz
https://www.cbc.ca/news/canada/calga...686433?cmp=rss
So becuase we get our electricity form burning natural gas, and natural gas buses exist, I'm really curious what the emmisions profile looks like between the 2 choices, and total life cycle costs including purchase price and fuel/electricity usage. I'd hope they did this analysis.
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1) Sorry, but I'm gonna be a bit pithy with this first bit.
Yeah, probably not. The people's who's job it is to make these kinds of decisions almost certainly didn't think to...you know, do their job. If only they had read a random message board post, they might have thought to do the analysis
2) Quick back of the envelope math
Diesel ICE Efficiency: 25-37%
But these are nat gas engines, which are 12-22%
https://ui.adsabs.harvard.edu/abs/20...to%2022%20%25.
For the power plants:
Combined cycle gas turbine efficiency: 50-60%
Typical coal plant efficiency: 35-38% (which makes up a pretty small part of Alberta electricity, and will be 0% by the time these busses are on the ground, but people like to bring it up when electric vehicles are mentioned)
Then there is a mix of other gas power plants, cogen, wind, hydro, etc.
Yeah, back of the envelope says, it'll be more efficient (the losses in transmission and charging will not be significant enough to make up the difference.
So yeah, electrifying NG busses will be more efficient from a carbon emissions point of view.
The way I look at it, all things being equal, prices is a proxy for energy intensity which is a proxy for carbon emissions. It's not 1:1:1, but it's a pretty good rule of thumb, especially if your comparing the same fuel (NG engine vs NG electricty generation)
If you're saving money for the energy use, then it's likely got a lower carbon foot print. Charging with NG powered electricity, is way cheaper than diesel, or a nat gas engine, so chances are, it's more efficient.