Are wood pellets a green fuel?

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James Watt's steam engine vaulted coal to its major role as a fuel for the Industrial Revolution. Today, about 40% of the world's electricity is generated in coal-fired power plants, consuming more than 80% of the coal mined each year. Because combustion of coal produces carbon dioxide (CO2) and other air pollutants, efforts to combat climate change have now turned to seeking alternatives to coal. Natural gas is cleaner and less expensive but, like coal, returns fossil carbon to the atmosphere. Recently, attention has focused on woody biomass—a return to firewood—to generate electricity. Trees remove CO2 from the atmosphere, and burning wood returns it. But recent evidence shows that the use of wood as fuel is likely to result in net CO2emissions and may endanger forest biodiversity.

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