Heather- a bioenergy crop to help meet UK energy needs?

A recently published study by scientists at a UK university has assessed the possibility of using heather (Calluna vulgaris) as a bioenergy crop. Led by Prof Fred Worrall, research suggests that in the UK heather burning currently releases 821 PJ annually, equivalent to burning 36,000 tonnes of coal every year.  Currently when heather is burned, the energy that is contains is released as heat to the surrounding environment, and greenhouse gases are also released.

Heather is present in upland areas across the UK, and is routinely burned in order to create suitable habitats for birds including grouse, and food in the form of new shoots for livestock such as sheep. Controlled burning is said to prevent the development of nutritionally poor heather, with long branches, and instead promote vigorous growth of healthier, “younger” plants.


However, by using heather as a bioenergy crop, the heat released from burning can be harnessed to provide heat or hot water to residential areas or industrial processes. Using a renewable source of energy can not only displace a proportion of fossil fuels, but also reduce the greenhouse gas (GHG) emissions.

However, any potential uptake in heather bioenergy needs to take into account the type of land from which it is harvested. In peat bogs, biomass is accumulated and locked away, resulting in a carbon sink. When heather is burned on peaty soils, there is an in the erosion of peat, which means there is a reduced ability to store carbon. Therefore, to be sustainable and reduce GHG emissions, any widespread use of heather for bioenergy would need to take place on areas which do not have the potential to be turned into functioning peat bogs.

The study by Durham University estimates that up to 11 tonnes of CO2eq per hectare could be prevented from entering the atmosphere from the use of heather as a bioenergy crop. Across the UK up to 2 061 tonnes of CO2eq could be saved each year if heather is harnessed instead of coal, which compares favourable to to other bioenergy crops such as Miscanthus and Willow.

The reported GHG savings for a range of common bioenergy crops in comparison to Calluna vulgaris (Heather):

Crop                                       GHG saving (tonnes CO2 ha−1 yr−1)               

Calluna  (heather)               −5.8 to −17.6

Miscanthus                            4 to −5

Willow                                    −3 to −4

Worrall & Clay 2014. Biomass and Bioenergy 64:140-151


Across the UK the average energy yield of heather was estimated to be 38 GJ per hectare per year, and in some regions could reach up to 57 GJ per hectare per year.

Although the yield of heather as a biomass crop may be relatively low, it has a very high energy efficiency, which far exceeds Miscanthus, straw and logging residues.


Energy yield and energy efficiency of a range of common bioenergy crops in comparison to the results from this study for Calluna vulgaris (heather):

Crop                                       Energy yield (GJ ha−1 yr−1)   Energy efficiency

Calluna                                  38                                                           63

Wheat                                    111                                                         6.7

Rape                                       89                                                           6.2

Potatoes                                 87                                                           3.0

Sugar beet                             163                                                         7.0

Logging residues                  5.2                                                          29

Straw                                      35                                                           23

Miscanthus                            279                                                         32

Willow                                    243                                                         78

Worrall & Clay 2014. Biomass and Bioenergy 64:140-151

There is also another potential advantage of Heather, which is that grows on relatively unproductive land, such as heaths and moors, for which there is little other use, and therefore little competition for land.  Other bioenergy crops such as short-rotation coppice, use much more productive land which has the potential to grow food.

The study leader Prof Fred Worrall said “We have a large source of very efficient, low-carbon energy growing naturally on our uplands, but we’re releasing all its CO2 into the atmosphere without getting any energy from it”

The UK is committed to meeting at least 20% of its energy needs from renewables by 2020, and the use of heather could contribute as much as 15% of the UK’s 2020 biomass target. Prof Worrall added “Surely it would be possible to send the heather down the hill and stop burning the coal”.


About biopadblog

Developing a local bioenergy market can provide significant opportunities for rural and remote areas, by improving security of energy supply, contributing to a reduction in CO2 emissions and stimulating the local economy by creating jobs and keeping payments for energy within the local community. A new project, BioPAD (Bioenergy Proliferation and Deployment), which targets the Northern Periphery of Europe, aims to ensure that bioenergy becomes more widely used and that awareness of the opportunities it provides are increased. The project will help the development of bioenergy and improve our understanding of the links between supply and demand by looking at supply chains for a variety of bioenergy fuels and different ways of converting these fuels into sustainable energy. Understanding the supply chains and the ways bioenergy moves from fuel source to energy provision will help the establishment of robust and efficient supply services which can match local demand. BioPAD is led by the Western Development Commission www.wdc.ie (Ireland) and is funded under the ERDF Interreg IVB Northern Periphery Programme (NPP) http://www.northernperiphery.eu
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