All the news that's fit to burn

Newspaper Innovation claims that in London every weekday, 400,000 copies of the London Lite and 500,000 copies of The London Paper hit the streets, almost literally as they are discarded on the floor. Have you ever wondered what that flow of newspapers would be worth as a source of energy?

My friend weighed an typical London paper and came up with 100 grammes. So we have just short of 65 tonnes of newspapers per day, every day, on average (i.e. averaging the weekdays over the weekend too).

What is a kilogramme of newspaper worth, in energy terms? Aysen Ucuncu at the Department of Civil and Environmental Engineering at Duke University comes up with a figure of 7540 BTU/lb, or 4.9 kWh/kg. So we can calculate 13 MW of potential thermal power flows onto London's streets, embodied in the carbon bonds of those free newspapers.

What could that potential be worth? Imagine you could collect all the newspapers up, without expending a single Joule of energy in the process, and burn them in a biomass boiler. Let's say you attached the boiler to a generator to make electricity at maybe 27% efficiency and sold it for £32/MWh, a typical long-term contract price for electricity from a waste-to-energy plant in London. You'd get £1m per year, or roughly 0.4 pence/newspaper.

Are the newspapers a significant source of energy? No. Burning them would supply only 0.04% of the average UK primary energy demand per person (13 MW of power over a readership of 7 million Londoners is 0.04 kWh/day/person, while average UK demand is 120 kWh/day/person).

Funnily enough, if you were to ever read one of these papers, it wouldn't be long before you read that you should unplug your mobile phone charger, for the sake of climate and energy security. But leaving a phone charger plugged in these days typically draws less than 1 W of electricity, or less than 0.02 kWh/day. You could generate electricity at more than five times that rate by burning your daily paper in the scheme above. Whether you thought it was worth reading first is up to you. All I can say is unplugging your mobile phone charger isn't going to save the planet.