PowerSwitch

This is an edited re-post of a topic that existed before the forums were hit by a virus in June 2005. Please feel free to add comments at the end.


I knew this idea but never knew the official name of the theory itself. Anyway...

Jevons paradox
From Wikipedia, the free encyclopedia.

The Jevons Paradox, named after its discoverer, William Stanley Jevons, states that as technological improvements increase the efficiency with which a resource is used, total consumption of that resource may increase, rather than decrease. In particular, Jevons' paradox implies that the introduction of more energy efficient technologies may, in the aggregate, increase the total consumption of energy.

In his 1865 book The Coal Question Jevons observed that England's consumption of coal soared after James Watt introduced his coal-fired steam engine, which greatly improved the efficiency of Thomas Newcomen's earlier design. Watt's innovations made coal a more cost effective power source, leading to increased use of his steam engine in a wide range of industries. This in turn made total coal consumption rise, even as the amount of coal required for any particular application fell.

Jevons' observation is not a logical paradox, but it is still considered paradoxical because it runs counter to the common intuition that improved efficiency enables people to use less of a resource.

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A Corollary to the Jevons Paradox
Localized solutions to global problems often confound the solution of the overall problem. Jevons paradox implies that as individuals become increasingly efficient, the overall economy will compensate by supporting additional individuals and increasing overall consumption.

For example, consider a green business which attempts to alleviate global environmental concerns by consuming renewable energy resources. If the business saves 10 units of energy from the local power plant which operates at 40% efficiency, they will save 1000 units of currency. This cost savings will allow the business to hire an additional two employees.

However, each of these two employees must commute to work in automobiles. These automobiles still consume 10 units of energy because they operate at only 15% energy efficiency. Thus by switching to renewable energy, the business has reduced the overall energy efficiency per unit of consumed resources from 40% to 15%.

By first saving money, then using it to hire two new employees, the green business has actually expanded the economy. The expansion of the economy will most likely result in an overall increase in energy consumption, which in the example above also shows the possibility of reducing energy efficiency by its effects in the wider community.

This paradox illustrates how difficult it is to solve global economic problems.

When the (in-use) energy efficiency of a product is increased, its day to day running costs decrease. If a device that was previously a luxury item, i.e. used by few, has its efficiency significantly improved, then the device will suddenly be made available to many more potential customers. Products that are already in the main stream (lights, refrigerators, washing machines, cars) are likely to be used more carelessly (in terms of energy).

I think that both of these factors (luxury & commonplace, and careless use) aid understanding of Jevons paradox. If the number of devices stayed the same following their increased efficiency, total energy usage would go down, but as their increased efficiency gives them a wider market and encourages careless use, total energy usage increases.

It is down to society's and the individual's response to greater efficiency: when a car is produced that does 90mpg, does the average consumer say, That's great - I'll buy that"; or do they say "Now I can have one for both me AND my partner".

As with anything - many factors to be considered: we live in an interdependent world."

Interesting but sounds like bad planning to me. I wonder if we had a system that balanced energy consumption with production (i.e. used energy rather than money as a means of control of production) would this paradox still hold?

This paradox is used in Peak Oil discussions often, tho it's not usually refered to be that name.

The PO-naysayers often use the old cars are much more economical than they were at the time of the last oil shock" as a reason why things are better now than they were oil-wise.

Yet they always overlook the fact that in 1979-80 the uk had like 8m cars (someone can correct me on the number!) and now it has 25m.

It's total efficieny of a resource use that matters not individual.

That wiki link is useful !"