An ambitious attempt to rank future energy sources according to myriad repercussions of their use has found biofuels to be the most undesirable option.
Use of ethanol caused the most climate damage, air pollution, damage to land and wildlife, and chemical waste, according to the analysis.
The study, which claims to be "the first comparative evaluation of proposed large-scale energy solutions to global warming, air pollution, and energy security", considered the implications of using each of 11 different energy sources to power three types of new-technology vehicles — run either on batteries, hydrogen fuel cells or ethanol fuel.
It weighted their contributions to global warming, air and water pollution and thermal pollution (for example from discharging power station coolants into water). It also considered their effects on water supply, land use, wildlife and resource availability. Indirect effects on energy security, nuclear proliferation, mortality and under-nutrition were also included.
The analysis found that wind power, when used as a source of electricity for battery vehicles, performed best. This combination came first in seven categories, "including the most important — mortality and climate damage reduction," said Mark Jacobson, director of the Atmosphere/Energy programme at US-based Stanford University and author of the study. Wind for fuel-cell vehicles came close behind.
In the second tier were battery vehicles using electricity from solar photovoltaics or concentrated solar power (which focuses a large patch of sunlight into a high-energy beam), and also from geothermal, tidal and wave sources. The third tier included battery vehicles driven by hydropower, nuclear, and coal from plants using carbon capture and storage.
The two liquid fuel options — ethanol in the form of corn-E85 and cellulosic-E85 —came last.
But Ned Xoubi fuel cycle commissioner at Jordan's Atomic Energy Commission, said: "Developing countries are in dire need of energy. The best choice for a sustainable, affordable, clean, available form of energy is nuclear".
"It has been one of the most competitive energy sources all over the world, costing less than wind power and requiring less land than wind."
And Magdi Tawfik Abdelhamid, biotechnologist at Cairo's National Research Centre, said: "Including biofuel in the list of the worst energy options is not scientifically justified. Producing biofuel using seaweed in developing countries could be considered as a cheap, environmentally friendly source for energy that doesn't endanger food security."
The study was published in Energy and Environmental Science last month (1 December).
Energy and Environmental Science doi 10.1039/b809990c (2008)