My 15th birthday was in 1976. I can’t recall that there was much memorable about it other than I still had hair and had just saved up enough to buy my first album.

In 1976 the households of Australia consumed 2,371 petajoules of energy.
Next year my youngest son turns 15. He is already onto his third iPod and way past his maiden download from iTunes.

He will use a tiny amount of the roughly 6,000 petajoules of domestic energy use – comfortably double the 1976 amount.

When he gets to my age, another 30 years will have passed. Projections have energy consumption by Australian households in 2050 at 17,000 petajoules, another doubling and seven times the 1976 level.

Nothing in the sums or the demand curves suggest that this doubling rate will slow, partly because there will be many more households, enough for the extra 12 million people. So if we want to stay at 2008 levels of energy use, each household in 2050 will need to use 30% less energy than we do now just to accommodate the increase in households.

We can’t do that by changing the light bulbs or even swopping our plasma screens for the new wafer thin stick-on screens that some clever engineer will invent. We will have to live in very different types of house, shower less, wear jumpers in winter and cop the sweat in summer.

Or we could change everything and use even more energy but from clean sources.

I think it will be the latter… and we have yet to fully grasp what that will mean.

M