Editor’s Note: Master Resource’s founder and editor, Rob Bradley, is currently struggling with the aftermath of torrential flooding in the Texas Hill Country. Until he can return to work, he has asked me to post “classic” MR entries. A blog post explaining Vaclav Smil’s concept of “power density” surely qualifies. This is the key concept for understanding a civilization’s energy needs.
Unfortunately, our MR files contain no concise explanation of the concept in layman’s language. (We have many explanations that no conceivable lay reader—myself most definitely included—could possibly understand or appreciate.) The closest thing I could find to a useful journalistic entry was a blog post by Kent Hawkins—a retired electrical engineer in Ontario—published on February 20, 2013. It is reprinted below.—Roger Donway, Managing Editor.
Power Density Separates the Wheat from the Chaff
By Kent Hawkins — February 20, 2013
“Power density (W/m2) is perhaps the most revealing variable in energetics…”[1]- Vaclav Smil
It may be a bit of an exaggeration to say that understanding power density may be all the average person requires to put our energy sources and needs into perspective, but there is some merit in this argument.…
“If the purpose is to show fuel consumption by various fuels in electricity generation, the correct measure is not the electricity produced but the fuel consumed with the impact of erratic and unreliable wind and solar generation accounted for.”
This is the second post in a series reviewing Power magazine’s article on the International Energy Agency (IEA) paper, the recent World Energy Outlook. Part I yesterday dealt with installed capacity projections to 2040 and showed that this was a misleading measure. This post will show that in understanding fuel consumption, simply reporting the electricity produced is also misleading.
To illustrate the trends in fuels for electricity generation, the Power magazine article shows a more complex chart of electricity generation flows (compared to the installed capacity in Part I), reflecting such things as the net effect of plant closures and new plant construction to arrive at a result for 2040.…
“The reality is that non-dispatchable generation technologies, (wind and solar) cannot be directly compared with dispatchable generation technologies (coal, natural gas, nuclear, biomass, and generally speaking, hydro). This is a common mistake.”
Unfortunately, unrealistic representations of wind and solar are alive and well in many publications. Even if mathematically correct, their ability to reflect reality should always be carefully assessed.
These are like maps that show only a few major features, such as coastlines, mountains, large rivers, and major roads, leaving out the likes of non-fordable smaller rivers, marshes, ravines, and steep slopes or cliffs.
Signs to watch out for: