The Rebound Effect: an assessment of the evidence for economy-wide energy savings from improved energy efficiency (5 Mb PDF warning)
It's a paper published in October last year by the UK Energy Research Center. It's a thorough review and meta-analysis of the research on what is now called the "rebound effect" in energy efficiency, which is the modern restatement of Jevons' original idea. I guess it had to be renamed in order to rehabilitate it out from under the shadow of the word "paradox" which of course, it's not. It turns out that researchers have been looking at this effect quite a bit in recent years. As you point out, there are significant complexities involved, and the effect is sometimes obscured by other factors.
The paper defines the effect this way:
Many energy efficiency improvements do not reduce energy consumption by the amount predicted by simple engineering models. Such improvements make energy services cheaper, so consumption of those services increases. For example, since fuel efficient vehicles make travel cheaper, consumers may choose to drive further and/or more often, thereby offsetting some of the energy savings achieved. Similarly, if a factory uses energy more efficiently it becomes more profitable encouraging further investment and greater levels of output. This is termed the direct rebound effect.
Even if consumption of energy services remains unchanged, there are reasons why energy savings across the economy may be less than simple calculations suggest. For example, drivers of fuel-efficient cars may spend the money saved buying petrol on other energy-intensive goods and services, such as an overseas flight. Similarly, any reductions in energy demand will translate into lower energy prices which encourage increased energy consumption. These mechanisms are collectively known as indirect rebound effects. The sum of direct and indirect rebound effects represents the
economy-wide rebound effect. Rebound effects are normally expressed as a percentage of the expected energy savings from an energy efficiency improvement, so a rebound effect of 20% means that only 80% of the expected energy savings are achieved.
The paper examines a broad range of research, and includes the following statements in the conclusions:
It would be wrong to assume that, in the absence of evidence, rebound effects are so small that they can be disregarded. Under some circumstances (e.g. energy efficient technologies that significantly improve the productivity of energy intensive industries) economy-wide rebound effects may exceed 50% and could potentially increase energy consumption in the long-term. In other circumstances (e.g. energy efficiency improvements in consumer electronic goods) economy-wide rebound effects are likely to be smaller. But in no circumstances are they likely to be zero.
and
Rebound effects vary widely between different technologies, sectors and income groups. While these differences cannot be quantified with much confidence, there should be scope for including estimated effects within policy appraisals and using these estimates to target policies more effectively. Where rebound effects are expected to be large, there may be a greater need for policies that increase energy prices.
Obviously, the examples you give of kitchen appliances and water pumps above don't demonstrate the effect easily. However, the fact that you were able to choose examples that present quantification difficulties or have other constraints does not invalidate the theory itself.
In the paper linked above, I especially commend to your attention section 3.4. In it the authors assess 17 research studies on rebound in private automobile transportation, which find long-run rebound effects converging around 20% or so. In section 3.5 they look at the rebound effects in home heating. Again, their meta-analysis shows rebound effects in the range of 10% to 58%. They also note that for time-intensive energy uses like washing clothes or watching television the rebound effects from improving appliance efficiency will be very small.
There is also a large section devoted to the analysis of economy-wide rebound effects, with the following statement as one of the conclusions:
The main insight from this evidence base is the dependence of the economy-wide rebound effects on the nature and location of the energy efficiency improvement, which makes any general statements regarding the magnitude of such effects questionable. However, while little confidence can be placed in the quantitative estimates, the frequent finding that economy-wide rebound effects exceed 50% should give cause for concern. Extending and improving this evidence base should therefore be a priority for future research.
This paper clearly shows that the ghost of Jevons is still stalking the research landscape, and significant supporting evidence has been accumulated.
As to your comment that authors' credentials are less important than their arguments or conclusions, I will say this. Their basic conclusion appears to be given in the title of the book, as well as the Amazon excerpt. The credentials of the authors serve to set our expectations about the rigour of their analysis and the resulting reliability of that conclusion (after all, given their reputations they have significant skin in the game). I would take the conclusions of a Giampetro that Jevons' theory is supportable well before the conclusions of a kristopher that it's hogwash.