Flows of Energy in the US Economy

A friend brought the following diagram to my attention and asked whether I have even seen it!  “Why yes,” I said, “the U.S. Dept. of Energy has been producing those for decades.” I reminded him — he is old enough to recall — that the administrations of Nixon, Ford and Carter made significant strides in the 1970s to bring public attention to renewable resources (alternatives to fossil fuels), to energy conservation (efficient use of energy), industrial cogeneration (AKA “combined heat and power” or CHP), and the potential for electricity pricing — reflecting marginal costs — to affect human behavior. “Dynamic pricing” is the term of art today, and the pricing specialists still have not figured it out!

Energy-Flow-Graphic (download PDF; Graphiti appears in Technology Review published by MIT, May/June 2010.)

When I reviewed the PDF carefully I saw a reference to the diagram’s creation in 1990. I knew that was wrong by a decade or two. I needed to prove to myself that this diagram (or a close relative) was of much earlier vintage. In an article “Energy Conservation” by Richard Merrill, in the second edition of Energy Primer (Dell Publishing, 1978), I found the following diagram. It was prepared in 1971:

The two charts show impressive amounts of waste in the production and transformation of fossil and other fuels into usable energy commodities.  They make the point that production could be more efficient; for example, by increasing conversion efficiencies, lower transmission losses, or capturing some of the waste heat that is otherwise lost. (Note: These two diagrams have different assumptions behind them and are separated by 39 years so a close inspection will reveal many differences.)

However, the charts do not show at all how inefficiently we use the energy flows which are labeled “usable” or “utilized” in the lower right corner! Note: “Useable” is the more accurate term because what happens to the commodity as it “leaves” this diagram is of critical importance. Both diagrams are inaccurate to a great degree if you take that perspective.

Our utilization of the energy commodity is tremendously inefficient.  For example, when you buy one unit — a kilowatt-hour — of so-called “usable electricity,” it may power a light bulb which converts only 15% of the electrical energy into visible light! (I assume a new, efficient light.) The other 85% of the energy labeled as “usable electricity” becomes heat.  Did you intend to “use” 85% of the electric commodity as heat? (Do you intentionally heat your home with lights?) Or is that a measure of waste not shown in the diagrams above?  It sure is.

I would argue that these diagrams are overly optimistic in their portrayal of energy flows. They track the commodity, but the commodity is just one input into the end use value that consumers seek.

Americans can do better.  To start, a smart analyst needs to begin where these commodity flow diagrams leave off. How much of the so-called “useable energy” is actually useful and how much is wasted?  How could we display that?


2 Responses

  1. As we move through time past the industrial revolution through to the end of the century responsible for the technology revolution. We may not realize how significant and precarious our current living conditions are placed. People born this century inevitably will have no idea that the society they are born into is living on a knife edge with regards to their basic needs. Electricity, food, shelter, water. One meteorite or solar flare and this could be gone in a flash….but people would still survive without emergency preparedness skills so this where they will suffer. If we start by not taking these things for granted and monitoring our electricity usage to understand what we do and do not need this would be a start. You can see more information under the articles section here http://polarbearplanetenterprises.com/Articles-Info.
    We the care takers need to impart information to our younger generations to prepare them and make our planet a better place.

    What do u think about that


    • Sven — More information about usage will help people make better choices, regardless of whether we are talking about energy efficiency or waste, vehicle efficiency (mpg or km/l), or the even fat or calorie content of food! Poor information about electricity usage is a long-standing problem in the USA. There seems to be a consensus emerging that advanced meters (and the “smart grid”) will result in new opportunities for consumers to become better informed, and to use more sophisticated (“smarter”) devices. There will certainly be efficiency gains from these changes.

      Regarding what will happen in coming centuries, or whether we respond appropriately at that time, I do not know. I would predict that within 10 years we will make substantial progress toward energy efficiency, reduced waste, more intelligent appliance purchases, better informed consumption and good investments in energy infrastructure.

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