Reply #10: Projecting the growth of renewables is a tricky business, all right. (plus a bit of bed-time sci fi)

[GliderGuider]

I tried to observe two criteria in my projections in that article.

The first was to keep my personal biases out of them insofar as possible. That meant using one of three approaches: use other experts' work that reflected some degree of consensus (which I did with oil and coal, and with some hand tailoring for gas and hydro); use numerical results from the literature with little change to their trends (the approach I used for nuclear power); and pure mathematical projections, which I did for renewables.

The second criterion was to be as optimistic as seemed reasonable. I wanted to be optimistic so as not to be easily accused of having a "doomer" bias that would invalidate the analysis from the outset. However, I didn't want to be so optimistic that I could be accused of biasing the outcome strongly in favour of one energy source or another.

The way I met these criteria for solar and wind was through a careful choice of the mathematical trend lines I used to extrapolate the historical production data. I wanted to find curves that fit the existing data very closely, but didn't just shoot off into the ozone after a few years. I wanted curves that would end up with a value at 2050 that passed a "reasonable man" test (would a reasonable man think they looked about right?) without me having to do anything beyond choosing the curve.

I found that Excel's polynomial extrapolations had the right look and feel, and fit the data very well. I did have a long argument with a proponent of solar power who was reviewing the document. He insisted that an exponential curve was more appropriate, even though it showed that solar power would be generating 100 times more than all the world's current energy by 2050 - hardly reasonable. I was unwilling to add in the arbitrary limit it would have required, so I stuck with the polynomial. The choice of a second order for wind and a third order for solar was based solely on how well each curve fit, and whether the result seemed prudently optimist.

So, the direct answer to your question is, each source was treated in isolation and the limitations imposed by declining oil and gas were not factored in, in the interests of optimism. It's the same reason I used the UN population figures rather than building in energy and environmental limits as I had in a previous article.

I plan to use the model in this article as the cornerstone for what I'm ultimately shooting for: a step-by-step narrative of how I think things are going to unfold over the next four or five decades. For the model to serve that purpose, it had to start with as few of my own assumptions as possible. The assumptions will get added in one at a time as I develop the story-line. Each chapter will build on the previous one and rely on the reader accepting the assumptions used to build it. So the base had to be clean.

Over the last few years I have very developed strong and pessimistic opinions about how things are going to unfold, which is why I'm trying to be extra-cautious in doing the analysis. For instance I think the effects of small but sharp disruptions in the world energy supply (short oil supply disruptions and electrical grid crashes in various places) will trigger cascades of failures in our civilization due to its lack of resilience.

Just for kicks, here's how I really, in my heart of hearts, suspect things will go:

A Tale Told by an Idiot, Full of Sound and Fury, Signifying Nothing

1. In five years or so a sharp drop in world oil exports (the "net oil export crisis") will coincide with a destabilization the world's debt structure to trigger a global depression.

2. In ten years, dropping oil supplies (the onset of the real post-peak slide) will prevent recovery and will deepen the depression.

3. This is also when the decline of the industrial and transportation infrastructure will start to interfere with the build-out of nuclear, solar and wind power. That will continue to get worse over the following decades.

4. The decline of gas supplies in 15 years will hit the world's fertilizer market with skyrocketing prices. This will trigger a decline in crop yields in the developing world (they have little discretionary income to reallocate for agriculture).

5. In twenty years the effects of Climate Chaos will become severe, amplifying the effects of the fertilizer and agri-fuel crisis. Famines will be in full bloom in Africa and Asia. Food and fuel riots become commonplace, resource wars break out in the affected regions, and floods of economic migrations will reach Biblical proportions.

6. At about the same time the continuing global depression will combine with the final crash of oil exports to create the conditions for a series of very intense regional wars. The likely participants will be everybody with nukes except maybe South Africa. I doubt it will turn into a classic global holocaust, but it will wreck many parts of the world.

7. In 30 years everyone that's left will be hunkered down in small isolated communities, trying to remember how to farm by hand and store food over the winter with no refrigerators. There will be about four billion of us by then, and our numbers will be dropping fast.

So you can see why I might want to keep my opinions out of my objective analysis. What I'm hoping is that as I build the chain of cause and effect one link at a time it leads ineluctably away from my worst fears. That would be a wonderful outcome, so I'm going to build that chain as objectively as I possibly can.

Paul Chefurka