The Role of Biomass in Achieving Net Zero


Using natural materials to meet the climate challenge sounds like a win-win – but it needs to be done with the environmental and social consequences in mind.Biomass – biological material derived from living or recently-living organisms – is coming under increased scrutiny over its potential role as a net-zero carbon energy source and contributor to a sustainable society. Biomass is argued to have the potential to help us meet the Paris Agreement goal of limiting global warming to well below 1.5 degrees Celsius. If managed sustainably, biomass will take carbon out of the atmosphere when it is growing and return it when burned, thereby creating a closed cycle that does not increase carbon dioxide levels in the atmosphere over time. Indeed, Scotland’s own Climate Change Plan lists biomass as one of the tools that can help us reach net-zero emissions by 2045.

However, although the use of natural materials to meet the climate challenge might sound like an easy win, the approach is controversial. There are debates over whether bioresources could be put to better use to meet some of the other sustainability challenges our society faces, like food security and manufacturing. There are also concerns over the impacts on biodiversity and ecosystems from large-scale intensive production of biomass. And it has been argued that producing biomass will put a disproportionate burden on people and places that are already disadvantaged. In this post, we take a look at some of the key points of contention around the use of biomass for net zero in Scotland, and reflect on what we need to do for biomass production to be socially just as well as scientifically appropriate.

Craigellachie Biomass Plant, Moray, which supplies heat to Macallan distillery and electricity to the national grid from timber (source:, CC BY-SA 2.0)

 How much biomass will Scotland have access to?

The UK already imports an unsustainable and inequitable amount of biomass. However, at the present time it is hard to know the full biomass availability within the UK due to the differences in terminology and methodology used by different sectors. Steps are, however, being taken to plug this gap. Within Scotland, Zero Waste Scotland mapped the bioresource arising across the country in 2017, and the data obtained was used to develop a unique Scottish Bioresource Mapping Tool. ClimateXChange also released in 2019 a report on the potential contribution of bioenergy to Scotland’s energy system. Data-driven approaches such as these are needed to so that predictions to 2050 on the role of biomass in achieving net zero can be evidence-based.

Another big problem for an evidence-driven response to biomass is that industry is developing at a faster rate than the science and data can keep up with. There are increasing levels of investment into innovative solutions that convert ‘waste’ material from the food, drink and agriculture sectors into key nutrients that have the potential to address important food security challenges. All of these activities have the potential to compete for available biomass. Moreover, although new innovations can offer significant societal benefit, we need to be careful to ensure that exploitation of bioresources does not lead to negative environmental effects elsewhere. Let’s take seaweed as an example. Scotland, especially the west coast and Western Isles, have been assessed as offering significant potential for growing seaweed on a large scale, which can then be turned into fuels and high-value produce. This has led to significant enthusiasm from research organisations, industry, and national and regional governments. However, concerns have been raised about the environmental impact seaweed cultivation may have on local biodiversity, carbon cycling, and coastal protection, and we cannot simply assume that because seaweed cultivation ‘works’ in other parts of the world that it will not have negative environmental impacts in Scotland. Studies investigating the impact of macroalgal harvesting, and indeed other new bioresource activities, in a specific Scottish context are therefore important before commercial-scale operations commence.

South-west Mull, near the site of a new community-owned seaweed farm (source: Leslie Mabon)

 Moreover, depending on the source, the production and harvesting of biomass can have vastly different impacts. Harvesting of long-standing biomass stocks such as peat bogs and old growth forests have been shown to lead to net greenhouse gas emissions, and to have drastic implications for ecosystems and biodiversity. However, biomass from forestry can be harvested sustainably or unsustainably, and the consequences for biodiversity change of forest gains and losses can be negative or positive. Some marine sources of biomass have the potential to be useful and minimally disruptive if managed and harvested sustainably. For example, treated fish waste has a variety of applications from animal feed to food packaging applications, soil fertiliser and biodiesel. Integration of fish farming with other aquaculture species (e.g. seaweeds and filter-feeding bivalves such as oysters and mussels) may help to reduce local environmental impacts by enhancing the natural recycling of waste, which in turn limits harmful processes such as carbon dioxide production and loss of oxygen on the seabed.

How should we use biomass to reach net zero?

Because biomass availability is limited, it is critical that we use it to the best of its abilities. We can use biomass as a renewable energy source, where it has a major advantage over wind and solar power in that it can be stored and used when it is needed. This may be valuable for sectors such as land transport and aviation where it is harder to switch to electric power. Biomass can be an important alternative to fossil fuels for heating, especially in rural locations where access to locally produced biomass is easy but access to other infrastructure is not. It can therefore be a suitable tool to fight fuel poverty if produced locally and sustainably. Biomass can also replace fossil fuel energy sources in the chemicals and materials sector, providing sustainable routes to a huge range of products including – but not limited to – surfactants, dyes, agrichemicals, coatings, plastics & packaging and binders for use in construction.

Looking forward, as we move to 2050 and technologies develop, bio-derived fuels for use in transport will likely lose their importance and the need for flexibility in the electricity system within rural locations will remain similar. But the need for bio-derived chemicals and materials is expected to dramatically increase as the bioeconomy expands to realise its estimated global economic impact of $4 trillion a year (half of which to be outside of human health) by 2040. However, incentives and prioritisations should be evidence-based and need to be supported by a full inventory of biomass availability, location and dependencies across the UK on which to base decisions.

From a societal perspective, just transition principles can guide us to understand priority uses of biomass, especially when it comes to identifying points at which biomass may offer economic and employment opportunities for sectors and places that do not have an easy pathway to transition away from carbon-intensive activity. A just transition may be defined as a transition to net zero that does not disadvantage workers in high-emitting sectors, or create new inequalities. Tests to assess priority use of biomass within a just transition could encompass potential contribution to national net-zero roadmaps (especially for agriculture and aquaculture), fit with workforce skills and employment needs, and coherence with regional land use plans. In their 2020 report on green recovery and nature-based jobs, NatureScot identified that nearly half of nature-based jobs in Scotland, for example, are in rural areas. Whilst many of these jobs exist in agriculture and forestry and may hence lend themselves to transfer or expansion to the production of domestic biomass, NatureScot also identify potential skills gaps in sectors relating to planning and management, for instance loss of ecological planning capability in local governments and the need for skills in understanding and managing natural capital. If the production of domestic biomass is to most effectively contribute to net-zero in Scotland (as well as broader sustainable development imperatives), there is hence a need to develop skills in job areas related to managing biomass and understanding its broader environmental impacts.

How can we ensure that biomass is sustainable?

It is important to remember that biomass is the mass of once living biological organisms. This will include potentially pathogenic and/or invasive species or biological and genetic material that could be a risk to human and ecosystem health. Biomass is considered a ‘greener’ and ‘cleaner’ solution but this is not always the case. For example, plant biomass grown on contaminated land could be useful in some applications such as chemicals and materials, but could be harmful if used elsewhere for example in domestic heating. Again, a key challenge here is ensuring that our laws and regulations are able to keep pace with the science and innovation.

There are also issues of fairness and equity globally when we think about the sustainability of biomass. As illustrated by the controversy over estimates of land available for reforestation published in the leading journal Science in 2019, it is vital that countries in the Global South are not disproportionately expected to take the burden of biomass production for the Global North. To ensure an accurate evidence base on which decisions about where biomass can sustainability be produced globally, it is vital that local researchers – who have fuller understanding of local land uses and conditions – are included as core partners in global research initiatives.

Conclusion: what should be the priority research and innovation actions from now on?

It is critical that Scotland continues to develop the skills, knowledge and infrastructure to be able to embed biomass within a circular economy – that is, an economy that designs out waste and pollution, keeps products and materials in use, and restores natural systems. Scotland was the first country in the world to join the CE100 Circular Economy Network. Scotland produces a multitude of biomass, has a great breadth of businesses working in, or relying on, the bioeconomy and is an academic leader in biotechnology research. Extensive UK & Scottish Government investment has grown the bioeconomy in Scotland, and it is therefore well placed to become an exemplar of a bio-based circular economy for the UK.

To sustain this leadership as we move towards 2050, however we need: techniques for bringing together different kinds of data that can show us how biomass works within bigger systems; engineering biology to provide bio-derived chemicals and materials; supportive platform technologies of automation and machine learning; and to expand our bioproduction facilities. It is also crucial that we remember that biomass production has to happen somewhere. Whilst rural and/or ‘remote’ regions may appear to be suitable for larger-scale biomass production due to lower population density, it should not be forgotten that such environments are themselves lived-in and working environments where a breadth of economically, socially and culturally significant activities continue to happen. It is thus imperative that local communities are engaged and consulted with at the earliest possible stage in locations where there is potential for scale-up of production, whether on land or on sea.

This blog post is based on a submission to the BEIS Call for Evidence on the Role of Biomass in Achieving Net Zero. Contributions to the text came from Louise Horsfall, Leslie Mabon, Heidi Burdett, Emilie Combet, Maria Dorenlas and Fiona Henriquez