I was emailing recently with Bradley E. Layton  Ph.D., Associate Professor in Mechanical Engineering and Mechanics at Drexel University, after reading his article A COMPARISON OF ENERGY DENSITIES OF PREVALENT ENERGY SOURCES IN UNITS OF JOULES PER CUBIC METER.  We had been bantering back and forth on the concept of simple pay back.  Sometimes if feels like there is really no such thing as simple payback, as we’re not comparing apples to apples.  The goal of his paper is “to provide a new perspective on how to compare energy sources on a more fundamental basis. Finally, the article provides a method of estimating the dollars-per joule for natural resources versus human resources and concludes with commentary on how political decisions may be affected by energy densities and energy costs.”

In the banter relating to the energy analysis SBS gives to a customer after an audit, Layton replied to me:

Dang dude, that’s a lot for one house. Do you give them a “break even” point? I would hate to have to go out and buy an new toilet if I was broke, if I knew it would only save me money on my water bill after I was dead.

Touche!  And right back to simple payback (and his toilet example above).  I agree on the simple payback on a toilet.  I think most folks would.  But we know the value of water and how simple it is to conserve, so we just buy the better toilet without the simple payback analysis.  So how do we get to apples on energy?  Hence, Layton’s article (and my response to his email above.)

Yes, we usually do include pay-back information.

But due to the size of this project and the client’s desires we didn’t feel like we needed to with them.

We’ve also developed some bigger picture financial payback info that looks beyond “simple pay-back” which is typically not a strong selling point of these technologies.

I had a chance to read your article more carefully. Very cool and something we struggle with all the time. (i.e… comparing energy savings between gasoline usage, propane usage, natural gas usage and electricity usage for our customers, each of them using a different measure.)

From a broader picture- here is something to consider: (just very rough notes)

From your article it is so very clear that oil and it’s derivatives are a massively compact and powerful source of energy. As we are forced to transition away from these fuels and from “the age of oil” is there anything on the radar screen technology-wise that offers similar amounts of energy in such a small package with the same mobility? Right now obviously the answer is NO, but can we expect to replace this incredible gift of energy that we have enjoyed for the last 200 years?

From an economic perspective, it is certain that the growth we have experienced in the last 200 years is absolutely tied to the amount of inexpensive energy we have had access to through these liquid fuels. To continue to grow and prosper as a species we must be able to continue to feed at the trough of an INCREASING energy source in a world that shows an ever DECREASING ability to provide this through traditional discovered forms of energy. Is it scientifically realistic to replace the amount of energy consumed currently, and to indeed, increase that level of energy consumption in order to continue to grow? Or are we doomed to run out of energy and see a decrease in growth of the species?

How much of a part does efficiency play in this equation? It seems that we can safely assume that there is generally speaking a 15-20% savings in energy to be had through efficiency measures. World wide we continue to waste large amounts of liquid fuels due to the fact that for so many years the supply was huge and the price was low.  If 15-20% is a safe number for “free, inexpensive efficiency measures that wouldn’t get in the way of growth” than how does that play in the macro environment of overall energy consumed and remaining supply.

STUDY IDEA NUMBER ONE- I suspect, that if one were to look at the overall total of available energy through liquid fuels remaining on the planet, as compared to the growing desire to utilize this energy by the earth’s human population, that we would see a near tragic confluence of graph lines coming in the near future. (20-50 years? or sooner?) Then, if one were to graph in the savings made possible through efficiency and the resulting decreased demand, would things look different? (I hypothesize, not really) Then, if one were to graph in the possible energy savings from current renewable technologies employed on a big scale what would the graph look like then?  Probably quite different, but I’m still not convinced that it can transition us from this oil boom train we have been on for so long, to another train of equal speed and size!

STUDY IDEA NUMBER TWO- Does this mean that we must invent new energy technologies to replace oil and it’s derivatives to sustain our growth as a species? Do we even want to try, given the population of the planet? If we don’t find a replacement at equal price and mobility, should we be working on designing a “soft landing” where the planet’s population will shrink slowly and without major unrest? What does that do our current economic models where shrinkage and non-growth are equated with death?  Can you design a society that is peaceful, sustainable, and healthy in an environment of economic shrinkage?

I’d love to see the first question addressed (simple analysis of the world’s supply of available energy as compared to the world’s appetite for the stuff.) Then so many other questions would come to light.

I’m sure someone is working on this already, if you see something will you pass it along?

Jeff Crouch, President
Sustainable Building Systems, LLC
www.SBSlink.com