Posted on Thu, 05/01/2014 - 09:10
Sankey diagrams provide perhaps the biggest, and most comprehensive picture of the energy systems that drive the Canadian economy. First created by Charles Minard in 1869 to map Napolean’s invasion of Russia, Sankey diagrams provide a graphical representation of large quantities of quantitative data. They are now widely used to depict energy systems. The line widths are proportional to the flows of energy from primary resources, through their conversion to fuels and electricity, to final consumption.
Click here to see an interactive Sankey of the energy systems of Canada in 2010 that is similar to the one shown here (click on the picture to enlarge).
The left-hand side of the diagram reflects the richness and diversity of Canada’s energy resources – biomass, hydroelectricity, coal, oil natural gas, and uranium. The production levels, like the other numbers in the diagram, are presented in energy units – Petajoules (PJ) – but the physical magnitudes are staggering. In more familiar units, the 1,446 PJ of primary hydropower translates into nearly 400 billion kilowatt-hours, more than 10% of the world’s hydropower production and enough to provide over half of the nation’s electricity consumption.
It is a prodigious amount of energy, and yet it is only about 10% of the energy content of Canada’s fossil fuel production. In 2010, the 6,680 PJ of primary oil production represents over a billion barrels, and the 7,035 PJ of primary natural gas represents 189 billion cubic metres. Even the much smaller quantity of primary coal production, 1,486 PJ, represents some 67 million tonnes, enough coal to fill a train that would extend from Vancouver to Halifax and back again.
And then there is uranium. Although often overlooked in tabulations of Canada’s energy production, the energy content in the uranium Canada produces (8,263 PJ in 2010, estimated by counting the heat generated when the uranium is used in nuclear power reactors) exceeds the energy content of both total oil and total gas production. In energy terms, uranium ranks as our largest energy resource, both in terms of production and exports.
All totaled, Canadian primary energy production in 2010 was nearly 25,600 PJ, and after including 3,700 PJ of imports, total primary energy availability was 29,500 PJ. As the Sankey diagram shows, 58% was exported, with the remaining 42% or 12,500 PJ being used domestically, 910 PJ for non-energy applications and 11,652 PJ for the provision of energy end use services to Canadians. The overall efficiency of energy end use Canada is about 32%, so in 2010 the actual useful energy delivered to Canadians, after conversion losses, was 3,712 PJ, just 13% of the total primary energy supply of 29,500 PJ.
Following the Sankey flows from left to right tells us a great deal about the use of fuels and electricity and Canada. For example:
- The transportation sector (1) runs mostly on petroleum (gasoline and diesel) and petroleum products are no longer widely used for energy outside of the transportation sectors.
- Natural gas (2) is the preferred fossil fuel for almost all stationary applications, where it is available, and is the fuel of choice for residential and commercial building heating and industrial process heat.
- Most domestic coal use in Canada is for power production (3); outside of steel and a few other industrial applications, coal is no longer widely used as an end use fuel in Canada.
- While wood (4) is a significant energy source of home heating in many parts of Canada, 4-5 times more biomass is used by the pulp and paper industry.
- As noted above, hydropower (5) is the largest source of electricity on a national scale; solar and wind and other primary renewable energy forms while growing in recent years are still a very small part of the national electricity supply.
These observations are made at the national level; there are large and important interprovincial variations. Also, the patterns revealed by the Sankey are constantly evolving. A comparison of the current situation with the Sankey for 1978, for example, shows the extent to which oil and gas exports have grown as share of total production, the decline of petroleum fuels in all the non-transport end use sectors, and the growth of natural gas as a feedstock in the non-energy sector.
There is a story behind every region and every line in the Sankey diagram; we will be using these visualization techniques in future blogs to tell these stories as a way to identify and understand the opportunities and challenges presented by the coming energy system transition.