Energy: The Achilles Heel of the Resource Pyramid

When economists say that we have far larger mineral resources today than ever before, they are usually referring to a model known as the resource pyramid. What they often fail to mention is that cheap, abundant energy is the key input into this model and that without it much of our presumed abundance would vanish.

In the classic 1954 book “The Challenge of Man’s Future” famed geochemist Harrison Brown posited a future in which there would no longer be mines, only processing facilities. With all the concentrated deposits of metallic and nonmetallic ores and helium (which is found in natural gas reservoirs) depleted, the only minable resources left for society’s needs would be rock, air and seawater. But, together they contain everything we need other than land-based food and fiber for modern civilization.

For example, granite contains many common metals such aluminum, iron, magnesium, titanium and manganese. Many more minerals including uranium are available in quantities of parts per million. Seawater contains most of the elements on the periodic table, the source of which is the erosion produced by streams and rivers feeding the oceans. The air contains rare “noble” gases that are important to industrial civilization including argon, neon, helium, krypton and xenon. The vast majority of the resources from rock, air and seawater, however, are at very low levels of concentration which is why granite and seawater are not currently being processed for their resource content (with the sole exception of salt from seawater). On the other hand, air is presently the only practical source for all the noble gases mentioned above except helium. These gases tend to be quite expensive since the processes for extracting them from air are very energy intensive.

Brown’s depiction is of a world at the bottom of the so-called resource pyramid. Economists use the resource pyramid model to explain why they believe humans will never run out of resources. If prices are high enough for a given resource, companies will have the incentive to develop previously uneconomic deposits, find a substitute for the high-cost resource, recycle and/or learn to do with less until a substitute can be found or new technology allows us to exploit resources that were previously technically impossible to extract. As we move down the resource pyramid, there is a lot more of any given resource to be had in the form of lower-grade deposits. The trick, of course, is to figure out how to extract these deposits economically.

Scitizen