Up to 25% savings if wood-based trash is converted into biofuel, says study
Judith Tan, Straits Times 13 Nov 09;
SINGAPORE could replace up to 25 per cent of its petrol usage if it converts all its paper, cardboard and wood waste into ethanol to be used as biofuel, say researchers at the National University of Singapore (NUS).
Last year, 1.5 million tonnes of paper and wood waste were generated, and nearly half was thrown away. The three scientists estimated that if this volume was converted into ethanol instead, it could replace a quarter of petrol consumption, with accompanying greenhouse gas emission savings of more than 29 per cent.
The main hurdle is that people do not separate their trash, making the logistics of conversion difficult, said Mr Allen Shi, a bio-science graduate and co-author of the paper.
He worked with his mentor, Associate Professor Hugh Tan of the department of biological sciences at NUS, and Dr Koh Lian Pin, a research fellow at ETH Zurich - the Swiss Federal Institute of Technology, on the paper, which was published this year in Global Change Biology: Bioenergy.
Ethanol, found in alcoholic drinks, is a form of renewable energy and is often used in a blend with petrol.
World ethanol production for transport fuel tripled between 2000 and 2007 from 17 billion litres to more than 52 billion litres.
Most cars in the United States run on blends of up to 10 per cent ethanol, with 10 per cent mandated in some states. In Brazil, it is compulsory to blend 25 per cent of ethanol with petrol.
In Singapore, another form of biofuel made from waste cooking oil has been available since 2006. There are now more than 400 vehicles and diesel equipment here which run on it.
'Converting waste to biofuels can potentially deliver more energy than the current method of incineration, so it is in Singapore's favour to develop the technology sooner rather than later,' said Prof Tan.
Mr Howard Shaw, executive director of the Singapore Environment Council, said that Singapore's challenge is to get people to separate their garbage.
It may have to be legislated.
'If you can fine people for not flushing, surely you can fine them for not separating their waste,' he said.
Last year, 3.34 million tonnes of waste in Singapore were recycled, out of nearly 6 million tonnes of trash.
