Using biomass as a replacement for coal in electricity generation was a seductive idea a decade or so ago. Pellets made from scrap timber, sawdust and shavings could be used to fuel our power stations. And since these came from trees that could be replaced, they were to all intents and purposes a renewable fuel. Unfortunately, that all changed once governments began to offer subsidies and big business began to grow trees to use as biofuel.
According to Michael LePage at New Scientist:
“While burning some forms of wood waste can indeed reduce greenhouse gas emissions, in practice the growing use of wood energy in the EU is increasing rather than reducing emissions…
“Overall, burning wood for energy is much worse in climate terms than burning gas or even coal, but loopholes in the way emissions are counted are concealing the damage being done.”
The main difficulty is that wood produces more greenhouse gas per MW of electricity than coal. Moreover, when forests are logged, their soils emit more carbon over the next 10-20 years.
“[Replacement] can take up to 450 years if forests do indeed regrow… To avoid dangerous climate change, however, emissions need to be reduced right away.”
As with corn ethanol, wood-burning is at best a semi-renewable fuel. It is only effective when it draws on a limited supply of waste biomass. Once it becomes an industry in its own right, the pressure to continuously expand simply makes it an additional problem to those we are already struggling with.
At the very least, the regulations now need tightening to ensure that governments are only providing subsidies to those using genuine waste wood.