When is renewable energy not renewable?

Chris Roberts and Alex Pointer, members of the Yorkshire and Humberside Green Party, question whether wood biomass is truly renewable, exploring its environmental and ecological impact.


Image by Szabolcs Molnar from Pixabay 

Chris Roberts and Alex Pointer

Most of us think that we know what the term ‘renewable’ means, but when it comes to energy, some forms are more renewable than others. One form of energy that we argue should not be considered renewable at all, when all relevant factors are taken into consideration, is wood biomass. Due to its ‘renewable’ designation, published figures indicate that we are making progress towards carbon neutrality. However, the truth is rather different.

The basic definition of an energy source being ‘renewable’ is that any carbon produced can be reabsorbed back into the biosphere from the atmosphere. This definition, however, fails to account for a crucial factor – how long the reabsorption takes. Even carbon produced by burning coal is ‘renewable’... if we give it the millions of years required to reform coal. We have just a few years to get our carbon emissions under control. Energy sources, we maintain, should only be defined as ‘renewable’ if they can reabsorb the carbon emitted within a short enough ‘carbon payback time’ to meet that deadline. Best estimates of how long it takes carbon from combusted wood biomass to be reabsorbed, through the regrowth of trees to replace those being burned, range from 44 to 104 years.

Research has found that per unit of electricity produced, generating electricity by burning wood biomass emits more carbon dioxide than coal. Under current legislation, however, power stations burning wood biomass for electricity are allowed to declare their carbon emissions as zero. This ruling stems from the 1997 Kyoto Protocol, which declared that countries producing electricity by burning wood biomass could count the resulting carbon emissions as zero (in order to create a declaration the USA, and one or two other rich nations, would be willing to sign). This was justified on the grounds that the country that the biomass was imported from would have already done a carbon count as part of the land management assessment of the effects of harvesting wood. This created a loophole open to exploitation, especially once the policy was adopted by the UN.

If the source country is not signed up to the UN Renewable Energy Directive, and not all countries are, no carbon accounting will have occurred at either end of the chain. However, even if a country is signed up to the Directive, neither the importing or exporting countries are currently required to account for the carbon cost of cutting, chipping, pelletising, drying and transporting the wood biomass, processes which account for approximately 15-20 per cent of the CO2 cost of biomass.

The existence of this loophole is particularly relevant to the UK, which relies heavily on importing wood biomass. Drax power station, for example, would use up the UK’s entire annual production in just 12 days. Despite overwhelming evidence for the global damage created by this loophole, the ruling was retained in August 2021.

But the problem doesn’t end there. There are ecological factors that impact atmospheric carbon that are not factored into any carbon accounting system and these factors have a huge impact of their own. 

A tree does not exist in isolation, but each one is the centre of an entire ecosystem of interdependent plants and animals, every single one of which – being a carbon based life-form – is also sequestering carbon.  The removal of trees from forests for biomass burning additionally decimates all the associated organisms in that ecosystem. Carbon reparation is further delayed, then, by the time required to entirely restore the ecosystem. Further damage can be caused if the trees removed from ancient mixed woodland are replaced with monocultures of fast-growing pine, as these trees are unable to support such richly diverse ecosystems so are never going to replace the total carbon sequestering capacity associated with the removed trees.

A common justification for burning wood biomass is that some of the wood used is classed as ‘waste’. Apart from the fact that there is much evidence out there of whole trees being used instead of wood collected from the forest floor, much of the carbon released by the decomposition process is recycled back into the food web by bacterial and fungal decomposers, and some makes its way into the soil rather than the atmosphere. Wood that is waste from manufacturing processes, such as sawmills, can be used in a plethora of alternative ways which don’t involve burning and therefore maintains the sequestration, such as in the building trade.

If business continues as usual, there is no guarantee that the replacement trees will survive to maturity to actually replace those harvested. Some will be lost to changes in land use, and others to the ever-increasing incidences of wildfire. The accumulating loss of trees ultimately leads us to the point of no return – a self-sustaining cascade of increasing CO2 emissions – quite the opposite of helping us reach carbon neutral in any time scale at all.

Currently, the burning of wood biomass for energy production in the UK is being propped up by billions of pounds in renewable energy subsidies, funded by the taxpayer. Revoking this funding would render wood biomass financially unviable. This could bring the process quickly to a halt, but could also create a large gap between energy supply and demand. This could be addressed, in part, by changing the way we all live and work; adopting a doughnut economy; reducing demand by repairing, recycling and repurposing instead of land-filling; active travel; less flying; insulating homes; conserving not destroying; installing heat pumps; better public transport; the list goes on.

We would also need alternative means of power generation – preferably that can respond to large fluctuations in demand. Other renewable sources are available, such as biogas derived from waste, poultry litter, or cleared invasive species. Alternative power options include green hydrogen, hydro, tidal, wave, geothermal, all of which are being researched and developed now, and could be making so much more progress with more funding.

To add insult to injury, our Government, which is set to host the upcoming COP26 summit in Glasgow, is claiming to be a ‘leader’ in green economics. The reality is that it has just delayed the Environment Bill for the fourth time, giving it nothing to take to the summit. What the UK Government does as the host of the summit sets an example for the rest of the world to follow – if the UK stopped labelling wood biomass as ‘renewable’, subsidies could usefully be redirected towards genuinely renewable sources of energy. Now, that would be an example worth following. 

The Green Party needs to step into the vacuum left by our Government at COP26. We need to take the lead and push politicians internationally to act now and stop the burning of wood biomass to generate electricity. We cannot afford to wait until we are elected to take action; to do so would be to commit the same globally catastrophic error the biomass industry is making in failing to recognise the significance of how long tree regrowth takes. ‘Political Action Time’ is our equivalent of the energy industry’s Carbon Payback Time.

If you would like to find out more or show your support for our campaign, the background paper to our motion, ‘Close the carbon accounting loophole in the Kyoto protocol’, can be found in the conference section of the Green Party’s Green Spaces.