the mile long glass

TheOilDrum | The longer straw - the future of fossil fuels (and most other resources)

The future of fossil fuels, particularly of oil, but also many other resources including water and minerals, looks problematic. People keep discussing proven reserves and whether peak oil already has arrived or not. Unfortunately, we will only be able to put this argument to rest in hindsight. But what is more important is the fact that - no matter how much additional oil we can still retrieve - future barrels will be much more difficult to extract relative to the past.

Drilling a hole in the desert and waiting for black gold to gush out is infinitely less complex than drilling a much deeper hole 5000 feet under water, as the public is now painfully beginning to understand. Many experts agree that we probably have used about 40-50% of recoverable oil. It is difficult to prove such numbers, but we may for a minute assume that this is true. For pessimists, this makes our glass half empty. For optimists, it remains half full. This has been the exact argument the energy community has been having, to little avail, so let’s play with that analogy some more: our oil reserves can be compared with a 1 mile deep glass full of our favorite drink. Getting the first sips is easy. Whenever we are thirsty, we lower a straw into the fluid and drink as much as we like. After a while, that straw might become too short, so we have to find a longer one. Not really a problem. We might even get better at making straws for a while. And so it continues.

But once we are half a mile down into this huge glass, the straw will be so long that one might need help to even hold it, and we will most likely require help to suck hard enough to make the fluid come all the way up. What has happened? We still have half of our favorite drink left, but the efforts to get to it are becoming increasingly painful, significantly diminishing the net benefit of that next sip. And so we might (have to) give up drinking long before the glass is empty, just because its too difficult to get at the fluid in a meaningful way, and because the effort of sucking eventually exceeds the benefit and joy from each sip.

The concept behind our "mile-long glass" analogy unfortunately applies to almost every raw material and energy source we are currently using. The more we have extracted, the more difficult it becomes to get to the next unit. Our organization (IIER) looks at this phenomenon using the term "Resource Return on Energy Investment" (RREI), which is based on established approaches used for Energy Returns on (Energy) Investment (EROI). It describes the amount of effort (energy) needed to get one unit of a resource we want to extract. To extract the next unit, our effort typically increases compared to the past, as we have mostly exploited the easy finds and must pursue the ones that are further away, harder to get, more difficult to secure politically, or any such combination. Over time, this increasing effort makes the production less and less useful to societies. Or to use our drinking straw example: at one point sucking out more from that glass exhausts us so much (e.g. the energy invested per sip becomes so big) that we will have to stop our effort and turn to something else, or - if there is no equivalent alternative - drink less.

When looking at RREI, almost all resources currently used in human processes show declines. Less "easy oil" means that we have to drill in hostile environments deep under the surface of oceans, lower ore grades mean that we have to move four times as much rock to extract the same amount of copper when compared to a couple of decades ago, and the depletion of groundwater sources translates to getting drinking water from desalination plants or from fossil (non-renewable) aquifers far away, at much higher energy cost.

This decline in easily extractable resources and the increased effort to retrieve them is much more important than the exact year when peak production of a particular resource actually occurs. It is today's reality, and helps explain why we are drilling at the bottom of the ocean at depths where no human being could survive for even a second.