What is biomass?

In the first of our series ‘Powering to net zero’, we examine the energy source that will enable our carbon negative future.

In the world of commercial power generation, biomass is the term we use to describe any organic matter we can use to produce energy.

Biomass can also describe organic material we use to provide energy in our homes. The fuel burned in wood stoves and wood pellets used to keep domestic biomass boilers running are both examples of this.

How do we use biomass?

Commercially, biomass has a wide range of uses, and comes in an equally wide range of forms. In electricity generation, it could take the form of compressed wood pellets — used in power stations that have upgraded from coal. Alternatively, it could take the form of biogas or biofuels, which are increasingly popular alternatives to fossil fuels in transport.

Biomass is any organic matter used to generate energy — including forest residues, plant material or wood.

Where do we get biomass from?

We can make biomass from many different sources. These include low-grade fibre created by commercial agriculture or forestry — knowns as ‘residues’ — which may previously have gone unused. Biomass also comes from dedicated crops grown purely for the energy industry and from organic waste products — like uneaten food.

Drax Power Station, near Selby, North Yorkshire, is the UK’s largest renewable power station. It produces enough electricity to power the equivalent of approximately four million homes.

The biomass generating units at the power station run on compressed wood pellets, which come from sustainably managed working forests in regions such as the southern United States, the Canadian west coast and the Baltic states of Latvia and Estonia. These pellets are largely made up of low-grade wood. This is a by-product, often made of left-over materials created during the production and processing of higher-value wood products, such as timber for constructionand furniture.

In order for their biomass to be certified as sustainable and responsibly sourced, biomass producers must comply with a number of stringent requirements.

Is biomass renewable?

Because biomass comes from living organic matter, it absorbs carbon dioxide (CO2) from the atmosphere as it grows. Provided it is grown through sustainable means, biomass is classified as a renewable energy source.

When it’s used as a source of energy, the CO2 released in biomass combustion is offset by the amount of CO2 it absorbed from the atmosphere while growing. This is because science says that this ‘biogenic’ or renewable carbon, is counted in the land use sector rather than by power generators.

Biomass — the facts

• In 2019 biomass was responsible 6% of Great Britain’s electricity generation — that’s more than 1/6 of the total generation of all renewable sources put together
• Modern biomass was first developed as an alternative for oil after its price spiked in the 1970s
• The International Energy Agency estimates that bioenergy accounts for roughly 1/10th of the world’s total energy supply

How long has biomass been used as a source of energy?

Humans have been using biomass for energy since the moment we first created a fire. Whenever our ancestors warmed themselves with fire from wood, plants or even animal dung, they were all creating biomass energy.

Wood is still a widely used energy source in many countries around the world. You’ll find biomass in the form of wood used to heat homes, and at much larger scale in power stations. It’s often used as a replacement for fossil fuels which have much higher carbon emissions over their entire lifecycle.

It’s clear that using biomass for energy is part of our history. It’s equally clear that sustainable biomass is very much part of our drive to a zero carbon, lower cost energy future.