Dangers in biomass burning

I started these posts in October 2007 and this is the 536th post. Many of these posts have been about the need to stop burning biomass. I have found some who have shared my views and also others whose blind faith in the benefits of biomass closed their eyes to the fact that burning biomass creates emissions which are significant and unnecessary.

Now it seems that the Environment Agency is coming round to my way of thinking. In theory biomass is supposed to be carbon neutral because new growth sequesters the carbon emitted and left to its own devices the dead biomass would rot, emitting carbon as it does so. There are, however, several “buts” to this simplistic and almost universally adopted view of biomass:-

1.       The well known “but” is the carbon cost of transporting biomass. There are plans to build a biomass power station in Port Talbot, and we can confidently expect that the biomass will be imported from Russia and Canada. There are many London Local Authorities whose view of complying with their own sustainability and low carbon rules is to permit biomass boilers (with a back up from natural gas boilers) ignoring the problems and carbon cost of delivering constant volumes of low mass bulky biomass pellets to be burnt in the middle of the United Kingdom’s largest city.

2.       If you leave wood to decay only a proportion of the carbon dioxide is emitted into the air; some of it is sequestrated in the soil; burning it prevents soil sequestration and commits all the carbon dioxide into the atmosphere, where it does the most harm.

3.       People burning biomass have no control over the people who farm and crop the biomass. To overcome the transport emissions and lack of soil sequestration that burning creates, it is certainly necessary to plant enough biomass to cover these losses, not just to replace the biomass. Merely planting enough biomass to recreate what you have burnt ignores the losses.

4.       Burning biomass harms air quality; this is a health issue. We may, if we are not careful, lose all the benefits of the Smoke Control Legislation enacted in the 1950s.

The Environment Agency has now realised that burning biomass can be more polluting than burning fossil fuel. Their studies show that while burning waste wood and MDF produce the lowest emissions burning willow, poplar, and rape seed oil creates the highest emissions. They have also studied the effect of farming grasslands to produce biomass crops – something that I reported over a year ago. Like me, they have found that the carbon dioxide spikes created when ploughing virgin land outweigh the benefits that the crop grown for burning brings.

The Environment Agency has suggested that we need to report biomass burning emissions; this is a very important suggestion, and one that we should act upon immediately.

We must stop looking on biomass burning as a sustainable and environmentally friendly source of energy. It has a role to play, but like fossil fuels, biomass burning must be carefully regulated and controlled. It should be used as a last resort, rather than as an alternative to the genuinely renewable and relatively harmless technologies of solar and wind.

Its most important role will probably be in combined heat and power operations of a certain scale. Provided these are close to the source of the fuel, carefully regulated and properly maintained and their emissions counted biomass has a future in the mixed energy requirements of the future. If we rush into large scale biomass burning we shall find that we have simply replaced one source of emissions with another.