Wood has been used as an energy source for centuries. But in the form of compressed pellets, a type of forest biomass, wood has been re-established to rival incumbent fuels such as coal. As a result, there are many misconceptions about where wood pellets come from and how they feed into Great Britain’s ever-decarbonising power system.
One of these is Duncan Brack, an associate fellow of the Chatham House think tank and a former UK Government special adviser. In a report published earlier this year, he makes a number of incorrect assumptions about biomass and the forestry industry. More than this, he fails to recognise some of the key reasons why biomass is an important and useful low-carbon energy source.
Here we look at some of the points critics of sustainable biomass fail to spot and detail why renewable wood pellets should remain a crucial part of our decarbonised power mix.
It’s making use of an ample resource
Perhaps the most common misconception of biomass is what it actually is. Whole forests are not being cleared to produce wood pellets. In reality, biomass is made up of residue wood fibre and low-grade wood harvested from responsibly managed forests, as part of the natural process of sustainable forest management.
Thinning – the process of periodically removing a proportion of trees from a growing forest – is common practice in silviculture as it reduces competition for resources and allows the most-promising trees to flourish. Were these weaker trees not removed, they would likely be crowded out by their stronger counterparts, causing them to die, decompose and release CO2 into the atmosphere. They would also detract from the health and growth of the remaining trees and overall forest.
It’s not destroying ecologically sensitive forests
As well as not flattening entire sections of land, biomass is not sourced from protected forests. Instead, it comes from commercially-grown, managed forests – such as those in the Southern USA, where Drax operates three of its own biomass production facilities.
More than that, the biomass market can help keep forests healthy. The majority of forests used for biomass are privately owned, so the economic incentive a market for wood products creates encourages land owners to replant felled stands and not overharvest in a way that is damaging to soil.
A healthy forestry industry is good for trees – and the environment
The harvesting and replanting of forest stands helps to increase a forest’s ability to absorb more CO2 from the atmosphere, as young stands of tree grow much faster than mature stands and need more CO2 to facilitate this process. This makes younger forests more effective carbon sequesters (absorbers) than older ones. Industries that economically incentivise the continuous growth of more productive forests then play a part in contributing to the number of young trees absorbing and storing carbon.
But a healthy forestry industry can have even more widespread effects. As well as being a massive employer across the US’ southern states, it can also protect natural environments. Urbanisation is the largest threat to forests in the region. Keeping the land valuable through wood and biomass demand prevents it being sold off to encroaching developers.
It can lead to a more flexible, stable energy system
Biomass is a low-carbon source of energy that not only offers cleaner electricity, but also the reliability and flexibility to drive further adoption of more renewables.
When intermittent services like solar and wind produce a limited amount of electricity (when wind is low and the sun isn’t shining) biomass offers a lower carbon alternative to fossil fuels. Converting existing coal power stations to biomass, as is the case at Drax, also helps reduce Great Britain’s coal usage. These large power stations can also offer the system services that are essential to grid stability and frequency control.
These advantages of biomass as an energy source, in addition to the environmental benefits of managed forestry and the importance of a healthy wood product market, highlight that while biomass usage in electricity generation is still in its infancy, it has a crucial role to play in the future low-carbon energy system supporting an increasingly electrified economy.
Read in full: Review and Comments Related to the Chatham House Report: Woody Biomass for Power and Heat Impacts on the Global Climate, prepared by Dovetail Partners, inc. with support from Drax Group plc