Powered by Trees Exploring the sustainability of biomass energy

By Tilde Bergström

The latest report from IPCC, the Intergovernmental Panel on Climate Change, declares renewable energy as one of the most important measurements in order to tackle global warming. One of those renewable sources is energy produced by biomass. The benefit of biomass energy is however a contested topic in the scientific world. While some deem it essential in the fight against climate change, others warn that the burning of biomass might do more harm than good.

Biomass energy is the oldest form of energy used by humans, ever since our ancestors were burning wood to cook food and keep warm. Today biopower accounts for about three-quarters of the world's renewable energy according to the International Renewable Energy Agency (IRENA). Biomass is an organic material, and its use for energy can be broadly divided into two main categories. One is organics grown with the purpose of transforming them into energy.

The other is residues from organic material, which can entail farm waste, municipal waste, and woody residues from the forest industry. There are then numerous different ways to convert biomass, or feedstocks as they are called, into heat and electricity. Biopower is not to be confused with biofuels, which are ethanol and diesel made from plants such as sugarcane and corn.

A statistical report published in 2020 by the World Bioenergy Association (WBA) shows that wood is the most common biomass feedstock for producing heat and electricity. The energy is most often generated by burning it in large industrial power plants. It can also be co-fired together with fossil fuels in order to reduce climate impact. Since wood has a fairly low density and contains moisture, it is getting increasingly popular to convert wood into pellets before burning. Wood pellets are small cylinders made from compacted sawdust. The WBA states wood pellets as one of the fastest-growing sectors within the bioenergy industry, with an annual growth rate of more than 11% since 2013.

The making of a renewable energy sourc

The status of biomass as a clean and renewable energy source could be traced back to the 1997 Kyoto Protocol, an international agreement led by the United Nations to target greenhouse gas emissions and climate change. In the protocol biomass burning is equivalent to solar and wind power in terms of carbon emissions. This is based on the assumption that any CO2 emissions released by burning biomass will be absorbed again as trees are replanted. This view on biomass energy was then adopted by the EU, legislating biomass as a carbon-neutral energy source in the 2009 Renewable Energy Directive. The directive also bound member states to have 20% of their energy from renewable sources by 2020. This sparked a boom in the demand for woody biomass, and according to the European Commission biomass was responsible for 60% of the EU’s renewable energy in 2019.

In order to fulfill renewable energy quotas, the biomass industry has been heavily subsidized. The largest biomass power plant in the world, Drax, is located in the UK. According to the Guardian, Drax received about 2,1 million pounds a day from the British Government in 2019 to fund the burning of biomass. Drax imports all of its wood pellets, and about 80% comes from North America. US-based company Enviva, which owns and operates ten plants in America, is the largest wood pellet manufacturer in the world. The UK, and Drax, is one of Envivas biggest customers. Earlier this year

Enviva announced plans to double their production by 2026, building six new pellet mills and increasing the yearly output from 6,2 million tons to 13 million tons.

Sustainable… or?

If biomass energy is an alternative to fossil fuels that even helps offset carbon, then why are some scientists raising concerns? Forests are vital ecosystems for our planet's health. The United Nations Environment Programme (UNEP) explains that forests have the capacity to remove carbon from the atmosphere, storing it in wood, plants, and soil. When trees get logged, that carbon is then released again, increasing our climate impact. Deforestation is responsible for about 11% of our carbon emissions according to UNEP. Furthermore, forests are very important for biodiversity as well as providing clean water and preventing erosion.

As previously explained, biomass energy is classified as carbon neutral since trees absorb carbon when they are replanted. However, this process takes time. In an open letter to the EU in 2018 signed by over 800 scientists, critical voices point out that it could take up to 100 years before that carbon is absorbed again. Compared to fossil fuels, this is of course a short time frame in terms of renewability, but climate change is moving even quicker. According to the UN, we only have 10 years to make drastic emission cuts.

Drax claims that wood pellets cannot be linked to deforestation and describes their energy as “climate positive, nature positive, and people positive”. They also emphasize that wood pellets are made from residues within the forest industry. Enviva however states on its website that only about 25% of its wood is sawdust and other waste products. The rest is sourced directly from logging trees. As mentioned earlier, Enviva exports a lot of its products to Drax. Both Drax and Enviva state they are utilizing forests in the most sustainable way possible. Climate organizations like Dogwood Alliance and Natural Resources Defence Council on the other hand accuse the companies of clearcutting environmentally and biodiversity important forests.

There is also an environmental justice aspect to the biomass industry. In an interview with BBC from 2021, one woman says that ever since Enviva opened up a pellet plant close to their homes in North Carolina, many community members have been experiencing health issues such as breathing problems and nosebleeds. Similar issues are raised in a recent report from Greenpeace magazine Unearthed, investigating pellet mills run by Drax in America. The mills pollute the surrounding environment with organic chemicals that have been linked to several negative health impacts including breathing issues, skin irritation, dizziness, and cancer. Drax has paid millions of dollars in settlements after three of their Louisiana pellet mills have been sued for breaking environmental regulations, Unearthed writes. These mills are more likely to be situated in deprived communities with high poverty levels.

Towards a green future

In 2021 the EU published a revision of its Renewable Energy Directive as an attempt to clarify sustainability criteria for biomass and to protect highly biodiverse forests. This indicates a broadening understanding that biopower is a complex question. Reusing different waste products to generate energy appears as a good strategy as the need for alternative energy sources is urgent. However, in this pressing transition, the preservation of vital pellet industry presents plans to expand, economic incentives might pose a threat to the sustainability of forest management. The environmental justice issues connected to the placements and pollution of some of the world's biggest wood pellet manufacturers also highlight another important aspect of the rush to renewable energy. Our energy needs to not only be green, but it also needs to be just. ♦