Jevons Paradox

When a lightbulb gets more efficient, do we end up using less energy, or more energy?

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Obvious, right?

[Or obviously a trick question, right?!]

The answer is that we end up using more energy overall.

As the individual bulbs become more efficient [and so cheaper], collectively, we end up using more of them. In addition to the energy those bulbs use when I flick a light switch, it’s also the energy [and physical resources] involved in producing more lightbulbs in the first place.

Counter-intuitively, individual efficiency leads to an increase in total energy usage.

This is known as Jevons Paradox, after 19th century economist William Stanley Jevons. He noticed that as steam engines improved, they got used more and more.

I’ve seen this in various places throughout my life - I grew up in a house with one television. While that TV was horribly inefficient by modern standards, with TVs and laptops and tablets and phones, we all have a lot more screens now. As another example, I was fairly early getting a mobile phone. That old Ericsson used a lot more energy than my current iPhone … but now we’ve all got smartphones - and we use them waaaaaay more than we used those early mobiles … Same with cars, flights, chatbots … the list goes on and on …

Focusing on efficiency is an example of ‘narrow boundary’ thinking: efficiency is only one part of the energy story. The full ‘wide horizon’ story of a simple lightbulb takes in production, usage and end of life, the energy and resources involved, and a whole bunch of other externalities - do LED lightbulbs affect our sleep patterns, for example?

Who knew that flicking a light switch was so complex?!

PS Jevons was talking about technology and energy, but the concept shows up in other areas … If you get more efficient at work, do you end up doing less work, or more work?!