Is biomass carbon neutral?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

A major UK energy supplier has been called into question when referring to their biomass as ‘carbon neutral’; claiming that their woody pellets neutralise carbon emissions due to the fact that new trees are planted to absorb gases, with scientific advisors now disputing this as biomass subsidies are due to expire in 2027.

This brings to the mainstream an interesting debate of whether biomass, and particularly woody biomass, is carbon neutral?

What does ‘carbon neutral’ actually mean?

The term ‘carbon neutral’ refers to the ability to achieve a balance between emitting carbon into the atmosphere and absorbing carbon from the atmosphere.

Currently, carbon neutrality is a driving goal for the UK in their efforts to significantly reduce carbon emissions and ultimately achieve Net Zero by 2050; turning away from energy generated by fossil fuels and towards renewable and alternative energy sources such as anaerobic digestion and Energy from Waste plants, green hydrogen projects, and Carbon Capture, Usage & Storage (CCUS) to achieve this.

It comes as no surprise, then, that - at this time - large-scale and industrial energy generation processes are being questioned on such a public level.

The question of wood burning

Alongside this, recently, the harmful effects of (personal) wood burning stoves has been highlighted on a governmental level; with stoves being banned in London from Feb. 2023 and ‘old’ wood burning stoves found to be 3700x more toxic than gas central heating [where EcoDesign stoves manufactured after Jan. 2022 are 450x more toxic].

And, although the issue of wood burning stoves and woody biomass are, of course, very different, they share an interesting common ground - burning wood.

The issues with burning wood

Burning wood on any scale creates carbon dioxide and, although it may be viewed by many as a relatively clean energy source due to the fact it is organic, the smoke emitted from wood burning is complex in its make up and includes over 100 hazardous chemicals that are toxic and carcinogenic; meaning that the issues with wood burning are not simply contained to greenhouses gases, but extend to a myriad of health risks and other, related, environmental risks.

Is biomass carbon neutral?

‘Biomass’ is an umbrella term that describes a renewable organic material that comes from plants and animals, and can therefore refer to a number of materials such as animal waste (manure), crops & plants, and wood & wood processing wastes and, the process of burning any type of biomass will inevitably produce CO2 in varying degrees which - for those wishing to achieve carbon neutrality or even reach carbon negative status - can be captured, used and/stored to further reduce emissions.

As such, biomass can be considered carbon neutral.

However, woody biomass specifically is what’s being questioned in this example and, although new trees are being planted to absorb the carbon emissions produced by burning wood pellets, burning wood can be as harmful - if not more - to the environment as burning traditional fossil fuels, not only in the CO2 produced, but in the other gases that serve to make up the smoke emitted by wood burning.

Therefore, surely if we want biomass to be carbon neutral, we need to move away from viewing wood & wood processing waste as a biomass as well as - more generally - moving away from burning wood; moving instead to viewing truly renewable energy generation processes, such as Energy from Waste and anaerobic digestion, supported by Carbon Capture, Usage and Storage, as carbon neutral biomass?