Wednesday, October 31, 2012

The Energy Pie

There’s a lot of chat these days about “sustainable” or “green” energy.
And a lot of confusion, too.
 “Green” energy means, here in BC, energy that is made using hydro, wind, or wood. Fossil-fuel energy – the kind that comes out of the ground – is not “green” or “sustainable”. So this is the kind of energy that environmentalists would like us to wean ourselves off of.
So let’s first wrap our heads around the size of the problem, and where the problem is. Here’s a graph, based on numbers from Canada’s government office on energy efficiency (2009 numbers), on energy use per sector here in BC:
[ energy use by sector and type ]

It’s colour coded: red pie pieces are “fossil fuel”, blues are “electricity”, and green is “wood”. It’s divided up by industrial sector: residential ("rez"), commercial / institutional ("comm"), heavy industry ("ind"), transportation ("trans"), and agriculture ("ag").
The idea here is that we want to reduce the size of the red chunks. The biggest red chunk is fossil-fuel-based transportation - moving ourselves and our stuff around - surprise, surprise! This chunk represents 33% of all our energy use here in BC, and it is more than twice as large as the total energy used by the residential sector. The next biggest red piece is the fossil fuel energy used by heavy industry (mining, forestry, cement) – which is 15% of our energy use – less than ½ of the transportation piece! Residential and commercial fossil fuel use (most which is used for water and space heating) is third on the list, and come in at about 7.5 and 5.5%, respectively.
[what surprised me was the huge amount of wood-fired industrial use. BC's energy hungy pulp mills use wood waste and what's leftover from their process to fire their boilers.]
So, moving to a more “sustainable” energy basis means we really need to get our transportation system onto electricity. Yeah, home heating could use some updates, but this is a much smaller problem if we want to reduce our fossil fuel use.
The real problem is, of course, that there is not enough electricity in BC right now to electrify our transportation sector. Basically, we are already using all of it. If we want to move our current transportation, as-is, to electricity, we’d need a futher 123PJ of energy from somewhere (taking into account the fact that electric motors are 3x more efficient than FF motors); this is the equivalent of 4.5 site C dams.
We can shrink the currently blue pieces of the pie (probably by 60%) by making better use of electricity…turning off lights, and especially trading in those baseboard heaters for (more expensive) heat pumps, would free up about 20PJ -  but that would still leave us with 100PJ to find somewhere. Still the equivalent of 3.5 site C dams…
It is really hard to escape the conclusion that we need to rethink our freight and human transportation systems if we want to move to more sustainable energy sources. The current system of commuting in single-occupancy vehicles, electric or not, cannot be part of this future.

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