An introduction to biomass
In ecological terms, biomass refers to any type of organic matter. It can derive from agricultural or forestry residues, or from dedicated energy crops or waste products (e.g. uneaten food). For as long as humans have used wood, plants or animal dung to make fire, we’ve been creating biomass energy (bioenergy).
For the 12 months ending 31 March 2024, bioenergy made up 82.6% of the renewable electricity that Drax Energy Solutions supplied to its UK business customers. So we want to be clear about how we source it and why the industry regards it as renewable.
But first, let’s investigate the different types of ‘bioenergy’ available.
More about bioenergy
It’s possible to use wood pellets for domestic boilers that run on biomass, and to use biomass logs in households with wood-burning stoves.
On a larger scale, the transport sector uses liquid forms of biomass – biogas and biofuel – to replace fossil fuels as an energy source.
Biomass is also an option at grid scale, of course – as at Drax Power Station, in North Yorkshire. See the ‘Biomass at Drax’ section, below.
Where does biomass for energy come from?
Organic-based feedstocks are derived from a number of sources, including waste, agricultural residues, purpose grown crops and forest products. Pellets like those that Drax Power Station uses are manufactured from low-grade roundwood and forestry and sawmill residuals. These materials are a byproduct of forest management and wood processing that produces higher value products like lumber and other solid wood products.
Biomass producers and users alike must meet a range of stringent measures. Their compliance ensures that the material they manufacture and/or use is sourced responsibly and certified as sustainable in accordance with relevant accreditation standards.
Is biomass renewable?
Biomass grown through sustainable means is classified as a renewable source of energy because these sustainable sources continually regrow after harvest. As biomass comes from organic, living matter, it grows naturally and absorbs carbon dioxide (CO2) from the atmosphere in the process.
When biomass is combusted as a source of heat or electricity, the process causes the release of CO2 that was previously absorbed by the material when it was growing. Regrowth of harvested materials then captures this CO2 again, forming part of the biogenic carbon cycle.
Biomass at Drax
To generate renewable electricity for National Grid, Drax Power Station uses biomass in the form of compressed wood pellets.
In 2003, the plant started exploring the co-firing of biomass alongside coal, which was its original energy source. Ten years later, the plant completed the conversion of its first generating unit to run only on compressed wood pellets. This lowered the carbon footprint of the electricity produced by more than 80% across the renewable fuel’s lifecycle.
Today, the plant uses compressed wood pellets sourced from sustainably managed working forests in the US, Canada, Europe and Brazil. Drax also utilises a small supply of agricultural residues. Drax also runs pellet production plants in Canada and the US South, and sells its biomass to customers in Europe and Asia.
Using sustainably sourced biomass at Drax Power Station helps to support around 6,000 jobs across the North of England. In contrast, coal-fired power stations throughout the UK that failed to convert to biomass have closed, with the loss of thousands of jobs.
These advantages are only the start of what biomass will enable us to achieve. We’ll look at the role of sustainable biomass in reaching net zero emissions in our next article.
