Biofuels and Greenhouse Gases
Tuesday, 25. September 2007, 15:51:05
In my post on Nitrogen and Bogs I wrote that “Biofuel may well be excellent to reduce emissions of the greenhouse gas carbon dioxide (CO2), but it emits plenty of nitrogen oxides (NOx), another greenhouse gas and pollutant”. This has now once again been confirmed by a new study led by Nobel prize-winning chemist Paul Crutzen (PJ Crutzen et al, Atmos. Chem. Phys. Discuss., 2007, 7, 11191).
Crutzen and colleagues have calculated that growing some of the most commonly used biofuel crops releases around twice the amount of the potent greenhouse gas nitrous oxide (N2O) - also known as laughing gas - than previously thought, wiping out any benefits from not using fossil fuels and contributing to global warming.
For rapeseed biodiesel, which accounts for about 80 per cent of the biofuel production in Europe, the relative warming due to N2O emissions is estimated at 1 to 1.7 times larger than the quasi-cooling effect due to saved fossil CO2 emissions. For corn bioethanol, dominant in the US, the figure is 0.9 to 1.5. Only cane sugar bioethanol - with a relative warming of 0.5 to 0.9 - looks like a viable alternative to conventional fuels.
In a report on the impact of biofuels, the Organization for Economic Cooperation and Development (OECD) said biofuels may "offer a cure that is worse than the disease they seek to heal." Biofuels may in fact hurt the environment and push up food prices. When acidification, fertiliser use, biodiversity loss and toxicity of agricultural pesticides are taken into account, the overall environmental impacts of ethanol and biodiesel can very easily exceed those of petrol and mineral diesel.
Some of my posts on biofuels:
Crutzen and colleagues have calculated that growing some of the most commonly used biofuel crops releases around twice the amount of the potent greenhouse gas nitrous oxide (N2O) - also known as laughing gas - than previously thought, wiping out any benefits from not using fossil fuels and contributing to global warming.
For rapeseed biodiesel, which accounts for about 80 per cent of the biofuel production in Europe, the relative warming due to N2O emissions is estimated at 1 to 1.7 times larger than the quasi-cooling effect due to saved fossil CO2 emissions. For corn bioethanol, dominant in the US, the figure is 0.9 to 1.5. Only cane sugar bioethanol - with a relative warming of 0.5 to 0.9 - looks like a viable alternative to conventional fuels.
In a report on the impact of biofuels, the Organization for Economic Cooperation and Development (OECD) said biofuels may "offer a cure that is worse than the disease they seek to heal." Biofuels may in fact hurt the environment and push up food prices. When acidification, fertiliser use, biodiversity loss and toxicity of agricultural pesticides are taken into account, the overall environmental impacts of ethanol and biodiesel can very easily exceed those of petrol and mineral diesel.
Some of my posts on biofuels:
WIDGETIZE