3 Comments »Posted on Wednesday 30 September 2009 at 7:28 am by Jacob Aron
In Climate Change & Environment


Turning our waste paper in to biofuel could replace over 5% of global petrol consumption, say scientists from Singapore and Switzerland. It would also reduce the burden on our rapidly filling landfills.

So-called “first generation” biofuels made from food crops such as corn or soy have been widely criticised as an unworkable solution to the energy crisis. Growing crops for fuel takes up valuable agriculture land and leads to higher food prices. Now, a new wave of biofuel producers are looking to alternative sources.

A study published in the journal GCB Bioenergy details the possibility of producing a fuel called cellulosic ethanol from waste paper and cardboard. The researchers created a model to estimate the amount of this waste in each country, and found that the potential for waste-based biofuel amounts to over 80 billion litres globally.

Clearly, the quantity of fuel that can be produced depends on the level of waste in each country. Nations like Sierra Leone could only manage to produce around a third of a litre of fuel per person each year, while Norway could potentially turn out nearly 50 litres.

Fuel demands also vary by country of course. By modelling this demand and comparing it with the potential for generating fuel from waste, the researchers found cellulosic ethanol could replace 5.36% of global petrol demand.

Cutting down on petrol also means reducing greenhouse gas emissions. The data on emissions from cellulosic ethanol is varied, but the researchers estimate that a switch to biofuel would save between 29.2% and 86.1% of greenhouse gas emissions.

“Our results suggest that fuel from processed waste biomass, such as paper and cardboard, is a promising clean energy solution,” said study author Associate Professor Hugh Tan of the National University of Singapore.

“If developed fully this biofuel could simultaneously meet part of the world’s energy needs, while also combating carbon emissions and fossil fuel dependency.”

SHI, A., KOH, L., & TAN, H. (2009). The biofuel potential of municipal solid waste GCB Bioenergy DOI: 10.1111/j.1757-1707.2009.01024.x

  1. 3 Comments

  2. The problem with ethanol is that the azeotropic mixture is about 95% alcohol, 5% water. You need to thrown in some benzene and a lot of energy to get the alcohol concentration to a level usable in a vehicle (unless of course you’re using it to fire a boiler). That would be why you can get up to 95% alcohol dirt cheap but ‘absolute ethanol’ always costs an awful lot more.

    Imagine the process used though – take green waste and possibly sort and grade it, chip it, mix into a huge vat with appropriate bacteria/enzymes and temperature control, wait a long time, filter, and process further for ethanol. Compare that to one method of commercial production from what is otherwise waste gas at an oil refinery: just add water and heat and bingo!

    Short story: if the bioreactive material can be supplied very cheaply, some people in small communities may consider doing this to create a supplementary cooking/heating fuel. On a large scale it would be too resource intensive with too long a turn-around time.

    You know what I’d do with waste paper and cardboard? I’d compact them and use them to fuel a boiler for a generator – MUCH less effort involved and it works – you just need a damn big parade of trucks loaded with scrap paper.

    By MadScientist on Wednesday 30 September, 2009 at 1:06 pm

  3. What I worry about is that however good an alternative to 1st gen biofuels (and fossil fuels obviously) we find the system changes needed to implement its use will most probably be cost prohibitive (on a nationwide scale).

    On MadScientist’s last paragraph I saw something recently about “houses of the future” where all the card and paper waste was made into pellets which then heated the house and fueled a generator.

    By Katie on Thursday 1 October, 2009 at 9:16 am

  4. The lab next to mine is working on ways of breaking lignin down into some form of biofuel as well. Still uses plant matter (as with first generation biofuels) with the noticable exception that ligninase plants could process *inedible* plant matter…which usually gets thrown away in food processing.

    By Lab Rat on Thursday 1 October, 2009 at 10:35 pm

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