Posted: Apr 10, 2013 2:07 am
The rest of the article gets into why what sounds like a bad idea is a bad idea.
Wood produces carbon twice over: once in the power station, once in the supply chain. The process of making pellets out of wood involves grinding it up, turning it into a dough and putting it under pressure. That, plus the shipping, requires energy and produces carbon: 200kg of CO2 for the amount of wood needed to provide 1MWh of electricity.
This decreases the amount of carbon saved by switching to wood, thus increasing the price of the savings. Given the subsidy of £45 per MWh, says Mr Vetter, it costs £225 to save one tonne of CO2 by switching from gas to wood. And that assumes the rest of the process (in the power station) is carbon neutral. It probably isn’t.
[...]
As another bit of the EU, the European Environment Agency, said in 2011, the assumption “that biomass combustion would be inherently carbon neutral…is not correct…as it ignores the fact that using land to produce plants for energy typically means that this land is not producing plants for other purposes, including carbon otherwise sequestered.”
Tim Searchinger of Princeton University calculates that if whole trees are used to produce energy, as they sometimes are, they increase carbon emissions compared with coal (the dirtiest fuel) by 79% over 20 years and 49% over 40 years; there is no carbon reduction until 100 years have passed, when the replacement trees have grown up. But as Tom Brookes of the European Climate Foundation points out, “we’re trying to cut carbon now; not in 100 years’ time.”
Wood produces carbon twice over: once in the power station, once in the supply chain. The process of making pellets out of wood involves grinding it up, turning it into a dough and putting it under pressure. That, plus the shipping, requires energy and produces carbon: 200kg of CO2 for the amount of wood needed to provide 1MWh of electricity.
This decreases the amount of carbon saved by switching to wood, thus increasing the price of the savings. Given the subsidy of £45 per MWh, says Mr Vetter, it costs £225 to save one tonne of CO2 by switching from gas to wood. And that assumes the rest of the process (in the power station) is carbon neutral. It probably isn’t.
[...]
As another bit of the EU, the European Environment Agency, said in 2011, the assumption “that biomass combustion would be inherently carbon neutral…is not correct…as it ignores the fact that using land to produce plants for energy typically means that this land is not producing plants for other purposes, including carbon otherwise sequestered.”
Tim Searchinger of Princeton University calculates that if whole trees are used to produce energy, as they sometimes are, they increase carbon emissions compared with coal (the dirtiest fuel) by 79% over 20 years and 49% over 40 years; there is no carbon reduction until 100 years have passed, when the replacement trees have grown up. But as Tom Brookes of the European Climate Foundation points out, “we’re trying to cut carbon now; not in 100 years’ time.”