"Our study shows that the potential for bioenergy production on marginal land is, in practice, very limited," says Josefin Winberg, one of the study’s authors and a recent PhD graduate in Environmental Science at Lund University. Her dissertation focuses on sustainable bioenergy production in agricultural landscapes.
In the study, researchers combined remote sensing with analyses of public land use data in southern Sweden. This was done to identify land that is no longer in use or only marginally profitable for farming, so-called marginal land. The purpose was to investigate how much marginal land is actually available for cultivating energy crops. An earlier study assumed that all land that has exited the agricultural subsidy system in recent decades could potentially be available for bioenergy production. This assumption has underpinned many national calculations of Sweden’s bioenergy potential.
Earlier Estimates Grossly Overstated
"We found that previous estimates of marginal land available for bioenergy production were significantly overstated. We also discovered that much of the farmland removed from agricultural production has been repurposed for other uses—typically grass fodder production or horse grazing," says Josefin Winberg.
Such land was identified as marginal in earlier studies as the absence of agricultural subsidies does not include the land in arable land data or as utilized in land use databases. In addition, small-scale farming is common on marginal land; because of its size, such farming rarely qualifies for agricultural subsidies, leaving it unaccounted for in public land use data.
Even if the land were "available," Josefin Winberg doubts it would be viable for large-scale bioenergy production.
"Often, these are very small plots, many less than 0.5 hectares, which limits their potential uses. It’s quite unlikely that we would cultivate energy crops on them without introducing additional financial incentives, as the profitability of using this land is currently marginal. Including this land in bioenergy potential calculations leads to inflated figures," she explains.
Aiming for Realistic Assessments
What happens if bioenergy is a desired resource in society, but the land presumed available is either nonexistent or inaccessible?
"If we want bioenergy, it has to come from somewhere, and the question is where," says Josefin Winberg.
She highlights the risks of producing bioenergy through alternative means. Cultivating energy crops on land currently used for food production, for example, is deemed unsustainable because it increases reliance on imported food, which may lead to land use changes with negative impacts elsewhere. According to the EU Renewable Energy Directive, marginal and abandoned agricultural land should be used for energy crop production. Consideration must also be given to biodiversity, ecosystems vital to human life, and areas important for carbon storage.
The researchers hope their study will help others make better, more realistic assessments of bioenergy production potential in the future.
"If we are serious about addressing climate and bioenergy issues, our assessments must reflect real production conditions. That’s our message. Above all, the study shows that the potential for sustainable bioenergy production on agricultural land in Sweden is quite low unless other societal changes, such as in food consumption, are made," says Winberg.
Link to study in Sciencedirect.com: https://doi.org/10.1016/j.biombioe.2024.107421
Link to dissertation (PDF), Lund University research portal: Pathways to sustainable bioenergy – navigating the energy-ecosystem services-biodiversity nexus in agricultural landscapes.
Facts: Agricultural-Based Bioenergy
Bioenergy is seen as a crucial stepping-stone when transitioning to a fossil-free society. The extent to which additional biomass can be sourced from forests is debated, given their importance as carbon sinks and concerns about the current biodiversity crisis. Agricultural-based bioenergy is therefore expected to play a larger role in the future. However, cultivating energy crops must not compete with food production. According to the EU Renewable Energy Directive, production should occur on abandoned agricultural land or so-called marginal land. This study investigates how much of such land is actually available, focusing on southern Sweden. Potential energy crops in agricultural landscapes include willow, hybrid aspen, poplar, reed canary grass, and ley crops.
Facts: New Dissertation on Sustainable Bioenergy
In her dissertation, Pathways to sustainable bioenergy – navigating the energy-ecosystem services-biodiversity nexus in agricultural landscapes, Josefin Winberg explores the challenges and opportunities related to agricultural-based bioenergy production in southern Sweden. Her focus is on sustainable land use, examining the interplay between different bioenergy strategies, ecosystem services, and biodiversity conservation.
Key conclusions from the dissertation:
- Ecosystem services and biodiversity impacts must be considered in parallel when evaluating bioenergy strategies to avoid conflicts between climate action and biodiversity preservation.
- Integrated energy crop production in intensively farmed areas can have positive effects on ecosystem services and certain species groups, provided it is combined with the protection of species-rich habitats. However, this requires significant financial incentives and has consequences for food production.
- There is a high risk of overestimating bioenergy potential from marginal and unused land if land characteristics and alternative uses are not considered.
Josefin Winberg identifies challenges in increasing agricultural bioenergy production without compromising other societal needs. However, she also sees opportunities for multifunctional and small-scale bioenergy solutions that could contribute to a fossil-free society when combined with sustainable food systems and reduced energy consumption.
Link to dissertation (PDF), Lund University research portal: Pathways to sustainable bioenergy – navigating the energy-ecosystem services-biodiversity nexus in agricultural landscapes.