Biogenic Carbon v’s Fossil Carbon

25 May 2024

There is serious confusion about carbon emissions and wood burning stoves for heating. The CO2 produced when burning wood for heating is biogenic carbon, which comes from a renewable source. This should NOT be confused with CO2 from fossil carbon which is not renewable (gas, oil, coal).

Comparing CO2 emissions from Wood Burning Stoves with other Fuels

Biogenic carbon circulates naturally within the environment, from plants and animals, to the air, the sea. and soil, and then back to plants and animals again.

Key examples of carbon facts and wood burning for heating can be found in links to reports and technical documents at the end of this article.

The carbon in wood used for heating is referred to as biogenic carbon. This biogenic CO2 does NOT contribute to climate change. This should not be confused with the CO2 produced when using fossil carbon which is not renewable (gas, oil, etc).

Biogenic carbon circulates naturally in the environment, from plants and animals, to the air, the sea. and soil, and then back to plants and animals again. 

Example: What’s the difference in CO2 produced from electric heaters and wood stoves? – Generating 1kW of heat from a modern stove produces 1/19th of the CO2 emissions of direct electric heating (at current grid carbon intensity and current wood processing and transport carbon intensity). So how does that work? Broadly, a little over 40% of current grid electricity is generated from renewables. So just under 60% of the 1kW of heat from direct electric heating comes from burning fossil fuel, which obviously produces CO2. The CO2 produced from generating 1kW of heat from wood burning relates to the CO2 produced during the processing and transport of the wood and not from burning it. The CO2 released when burning wood for our heating is biogenic and forms part of the natural (non fossil) carbon cycle.

Heat pumps are very efficient. But at current grid carbon intensity levels, even a good heat pump produces around 5 times as much CO2 per kW of heat as an efficient wood stove. Of course, the CO2 emitted through using a heat pump will reduce over time as more of our future electricity is generated from renewables. But, by the same token, the CO2 emitted through the processing and transport of wood will reduce to zero over time as all of our industry decarbonises.

The following documents are useful for understanding some carbon facts when comparing wood to other heating. The technical information has been produced in response to regulation change and potential legislation in Scotland. The ‘carbon facts’ are equally relevant to the whole of the UK.

Key Facts Scotland 25th April ’24 (see carbon facts on page 2)

Key Arguments Scotland May ’24 – why efficient wood burning is part of the CO2 and climate change solution

Biogenic carbon CO2 cycle

• Carbon dioxide (CO2) from air is absorbed by trees, plants and living things as ‘biogenic carbon’
• Trees store the CO2 (biogenic carbon) in the wood’
• Processing wood for fuel currently releases small amounts of CO2 but even this will fall to zero as all industry decarbonises
• Decomposing wood returns CO2 back to the air. Burning biogenic carbon for heating returns CO2 back to the air and soil and the cycle begins again.

So whether wood decays naturally or is used for building or making things, or if it’s burned, the carbon (CO2 ) is always biogenic and will be returned to the natural environment to start the process again.