Diverse but finite

Biomass is in abundant supply. It comes in the form of foodstuffs, such as cereals, fruit and sugar. And we are familiar with its uses as a material input: timber in the manufacturing of paper and other goods, sugar crops in biofuels production, cotton in the garment industry … the list goes on. And let’s not forget bioenergy, which now represents around 80 per cent of the world’s renewable energy supply. Biomass is everywhere. And no wonder, for it has a lot to offer. But how is it cultivated? When is it genuinely green and low-carbon? And how much potential does it have to offer, also in terms of sustainability?

“Biomass has many different applications and demand is set to increase,” says Hannes Böttcher from the Oeko-Institut. A Senior Researcher in the Energy and Climate Division, he is well aware that meeting this demand will not be an easy task. “Biomass production can’t be increased at will,” he explains. This is because the supply of fertile land available globally is limited: indeed, the amount of arable land will have to increase simply to enable the world to achieve food security (see A question of ethics – Biomass use, p.8). And on much of the land already being farmed, sustainability issues mean that there is limited scope to expand production. Intensive farming, often involving the use of pesticides, unsustainable irrigation systems, monocultures and inadequate soil protection, can have negative impacts on the environment and climate. “Of course, there’s no disputing that biomass use offers many benefits, not least for the climate. It is regenerative, it helps to store carbon in wood products for the long term, and it is a good substitute for fossil fuels and helps to reduce greenhouse gas emissions. However, there are clear limits to its potential, beyond which it does more harm than good,” says Hannes Böttcher. “In Russia, for example, substantial amounts of timber are being felled in intact forests, with very little replacement planting taking place, and this is causing forest degradation. The overall carbon footprint of this type of approach is negative, regardless of how the wood is used.”

Environment and climate

So what are the negative impacts of bioenergy production and how can they be mitigated? These questions are being explored by Oeko-Institut experts involved in the Study on Impacts on Resource Efficiency of Future EU Demand for Bioenergy (ReceBio) on behalf of the European Commission. Together with a consortium of five partners, including the International Institute for Applied Systems Analysis (IIASA) and the Institute for European Environmental Policy (IEEP), the Oeko-Institut is analysing the impacts of EU bioenergy production on resource efficiency by investigating, among other things, the EU’s current uses of bioenergy, their environmental impacts, and interactions with sectors that use biomass. During the course of 2015, the research partners will also look at a range of scenarios based on various assumptions about the intensity of biomass demand, and the associated impacts on the environment and resources. “Biofuels do not form part of the ReceBio project. What we are doing is to look at the use of biomass in power and heat generation. Wood pellets are an example: they are one of the EU’s key imports, mainly from North America,” explains Hannes Böttcher.

In a desk review of the literature, which formed part of the project and has already been completed, the researchers investigated the possible impacts of bioenergy production on biodiversity, soils, water and greenhouse gas emissions. “As regards biodiversity, the intensification of land use and particularly land-use change have negative effects if, for example, forests are cleared and converted into arable or grazing land,” explains Hannes Böttcher. On the other hand, farmland can benefit from a switch to biomass production. “Short rotation coppice (SRC) plantations are a good example: these involve the cultivation of fast-growing crops, such as willow, which require less soil tillage. This has a beneficial effect as it promotes carbon enrichment in soils.” But there may be adverse impacts on the soil as well. “These can include soil erosion, nutrient loss and salinisation.” Cultivation of energy crops can also be detrimental to water resources and the climate. “In the water sector, the main problems that we are identifying include excessive water use and pollution of water resources, often with pesticides,” says the Oeko-Institut’s expert. “And with the climate, there are both positive and negative impacts. The climate footprint is highly dependent on the supply chain as a whole: in other words, it all depends on how the biomass is grown, harvested, transported and processed and how it is ultimately used. To measure the footprint, we have to identify and assess every link in the chain.” Certification of biofuels is mandatory in the EU, with minimum standards on greenhouse gas emissions and other environmental impacts. Questions are asked about product performance in these thematic areas – and producers and importers must have the right answers at their fingertips.

Safeguarding sustainability

In their study, the researchers have assembled a wide range of proposals on mitigating the negative impacts of biomass cultivation. “Key steps include protecting sites with rich biodiversity and leaving deadwood and old trees in situ in woodland,” says Hannes Böttcher. “Where soils are concerned, limiting or prohibiting the removal of crop residues and tree stumps from areas with sensitive soil structures is important.” A key factor in protecting water resources, he adds, is to prevent over-extraction of water reserves in water-poor regions and, more generally, to curb pollution. “In terms of the climate footprint of bioenergy, too, there is scope to take action,” he says. “Soils which are rich in carbon – such as peatlands – should not be ploughed up. The same certainly applies to ancient woodland. It is also important not to make excessive demands on commercial forests: the volume of timber harvested should never be higher than the volume of growth.”

Besides these practical proposals for more sustainability in biomass cultivation, there are numerous steps that can be taken more generally to mitigate the impacts on the environment, climate and society. “One option is to establish certification schemes for biomass products from sustainable sources,” says Hannes Böttcher. “One possible model is the Forest Stewardship Council’s FSC label, which promotes responsible forest management.” However, certification tends to be voluntary. Agreements with producer countries and the adoption of clearly defined standards for imports into the EU can therefore potentially make an important contribution as well. They should be applicable on an EU-wide basis, like the Forest Law Enforcement, Governance and Trade (FLEGT) agreements, which have existed for some years and aim to combat illegal logging. The EU’s current sustainability standards for biofuels do not go far enough, according to Hannes Böttcher. “The problem is that the standards only apply to liquid biofuels, not to solid biomass or other biomass applications. The standards are limited in scope and this can cause displacement effects. In other words, crops such as rape may be certified as sustainable, but if they are used to produce biofuels, this leads to a greater environmental impact of food production, in this instance vegetable oil, to which no such standards apply,” he says.

Recycling and efficiency

More widespread use of these measures can make biomass more sustainable. However, its potential is limited in one key respect: it will never replace fossil fuels completely. In the EU, the sustainable bioenergy potential amounts to an estimated 20 per cent of current energy consumption. This is heavily dependent on other countries’ ambitions to step up their biomass use. “We cannot simply aim to replace fossil fuels and materials with biomass. Regenerative raw materials don’t offer that potential,” says Hannes Böttcher. He is also critical of the concept of the Bioeconomy, in other words, a biobased economy, which he thinks does not go far enough. “Biomass is certainly regenerative, but it is still a finite resource. So we need to go further – by expanding recycling systems, for example, and improving biomass efficiency.” Key steps in this process, says Hannes, are closing the substance cycles and avoiding post-harvest losses (see A question of ethics – Biomass use, p.8). “Measures to improve the recovery and use of wastes and residues are also important; one example is the separation of biological waste, which is meant to happen across the EU, but there are still major gaps in practice.” So yes, we have biomass in abundance – but not enough to waste. Christiane Weihe