I received a helpful suggestion in my office email regarding the Institute’s CO2 footprint. The message advised that I turn off my PC before leaving work since collectively all those PCs must be drawing a huge amount of electricity. Some reports estimate the IT infrastructure causing CO2 outputs comparable to the airline industry. So it seems to make a lot of sense that we should always turn off our PCs at the end of the work day. However, today the UK Energy Research Centre (UKERC) released a report that explains how the “rebound effect” can significantly reduce the impact of such well intended emission savings.

Energy savings in UK households could be up to 30% lower than previously thought, jeopardising efforts to cut the nation’s carbon dioxide emissions.

As people cut their bills by using more efficient devices, they tend to spend the extra money buying additional goods that cancel out some of the savings.

This is simply another instance of Jevons Paradox at work. The report’s author, Steve Sorrell, explained how the paradox manifests itself both directly and indirectly:

He used the example of someone buying a fuel-efficient car as an example of a direct rebound effect.

“It should mean that I use less petrol, that’s the assumption,” he said. “But because I am using less petrol, my running costs are less.

“As a result, I may choose more often, I may choose to drive to the shops rather than take the bus.

“In the end, I may drive further because driving is cheaper and that will offset some of the energy savings. The energy consumption per mile may be less, but I am driving more miles.”

To illustrate an indirect effect, Mr Sorrell said that if he did not drive more miles then he would save money, which he could spend on other goods and services.

“To take an extreme example, I could put some of that money towards an overseas holiday.

“In which case, some of that money is being spent on kerosene, so there is energy being used elsewhere in the economy as a result of me saving money on my car travel.”

So I’m not going to feel too guilty if I forget to turn off my PC at night. However, I do run the Climate Prediction screensaver application via BOINC software. So it isn’t all a waste.

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