Birka Wicke

Indirect land use change: review of existing models and strategies for mitigation

This study reviews the current status, uncertainties and shortcomings of existing models of land use change (LUC) and associated GHG emissions as a result of biofuel production. The study also identifies options for improving the models and conducting further analysis. Moreover, because the extent of indirect LUC related to biofuels largely depends on other land uses, particularly agriculture, this study explores strategies for mitigating overall LUC and its effects. Despite recent improvements and refinements of the models, this review finds large uncertainties, primarily related to the underlying data and assumptions of the market-equilibrium models. Thus, there is still considerable scope for further scientific improvements of the modeling efforts. In addition, analyzing how overall LUC and its effects can be minimized is an important topic for further research and can deliver more concrete input for developing proper policy strategies. Future studies should investigate the impact of sustainability criteria and the effects of strategies for mitigating LUC, such as increasing agricultural efficiency, optimizing bioenergy production chains, using currently unused residues and byproducts, and producing feedstocks on degraded and marginal land.

The global technical and economic potential of bioenergy from salt-affected soils

This study assesses the extent and location of salt-affected soils worldwide and their current land use and cover as well as the current technical and economic potential of biomass production from forestry plantations on these soils (biosaline forestry). The global extent of salt-affected land amounts to approximately 1.1 Gha, of which 14% is classified as forest, wetlands or (inter)nationally protected areas and is considered unavailable for biomass production because of sustainability concerns. For the remaining salt-affected area, this study finds an average biomass yield of 3.1 oven dry ton ha−1 y−1 and a global technical potential of 56 EJ y−1 (equivalent to 11% of current global primary energy consumption). If agricultural land is also considered unavailable because of sustainability concerns, the technical potential decreases to 42 EJ y−1. The global economic potential of biosaline forestry at production costs of 2€ GJ−1 or less is calculated to be 21 EJ y−1 when including agricultural land and 12 EJ y−1 when excluding agricultural land. At production costs of up to 5€ GJ−1, the global economic potential increases to 53 EJ y−1 when including agricultural land and to 39 EJ y−1 when excluding agricultural land. Biosaline forestry may contribute significantly to energy supply in certain regions, e.g., Africa. Biosaline forestry has numerous additional benefits such as the potential to improve soil, generate income from previously low-productive or unproductive land, and soil carbon sequestration. These are important additional reasons for investigating and investing in biosaline forestry.

Projections of the availability and cost of residues from agriculture and forestry

By‐products of agricultural and forestry processes, known as residues, may act as a primary source of renewable energy. Studies assessing the availability of this resource offer little insight on the drivers and constraints of the available potential as well as the associated costs and how these may vary across scenarios. This study projects long‐term global supply curves of the available potential using consistent scenarios of agriculture and forestry production, livestock production and fuel use from the spatially explicit integrated assessment model IMAGE. In the projections, residue production is related to agricultural and forestry production and intensification, and the limiting effect of ecological and alternative uses of residues are accounted for. Depending on the scenario, theoretical potential is projected to increase from approximately 120 EJ yr−1 today to 140–170 EJ yr−1 by 2100, coming mostly from agricultural production. To maintain ecological functions approximately 40% is required to remain in the field, and a further 20–30% is diverted towards alternative uses. Of the remaining potential (approximately 50 EJ yr−1 in 2100), more than 90% is available at costs <10

Model collaboration for the improved assessment of biomass supply, demand, and impacts

2005 GJ−1. Crop yield improvements increase residue productivity, albeit at a lower rate. The consequent decrease in agricultural land results in a lower requirement of residues for erosion control. The theoretical potential is most sensitive to baseline projections of agriculture and forestry demand; however, this does not necessarily affect the available potential which is relatively constant across scenarios. The most important limiting factors are the alternative uses. Asia and North America account for two‐thirds of the available potential due to the production of crops with high residue yields and socioeconomic conditions which limit alternative uses.

Energy demand and emissions of the non-energy sector

Existing assessments of biomass supply and demand and their impacts face various types of limitations and uncertainties, partly due to the type of tools and methods applied (e.g., partial representation of sectors, lack of geographical details, and aggregated representation of technologies involved). Improved collaboration between existing modeling approaches may provide new, more comprehensive insights, especially into issues that involve multiple economic sectors, different temporal and spatial scales, or various impact categories. Model collaboration consists of aligning and harmonizing input data and scenarios, model comparison and/or model linkage. Improved collaboration between existing modeling approaches can help assess (i) the causes of differences and similarities in model output, which is important for interpreting the results for policy‐making and (ii) the linkages, feedbacks, and trade‐offs between different systems and impacts (e.g., economic and natural), which is key to a more comprehensive understanding of the impacts of biomass supply and demand. But, full consistency or integration in assumptions, structure, solution algorithms, dynamics and feedbacks can be difficult to achieve. And, if it is done, it frequently implies a trade‐off in terms of resolution (spatial, temporal, and structural) and/or computation. Three key research areas are selected to illustrate how model collaboration can provide additional ways for tackling some of the shortcomings and uncertainties in the assessment of biomass supply and demand and their impacts. These research areas are livestock production, agricultural residues, and greenhouse gas emissions from land‐use change. Describing how model collaboration might look like in these examples, we show how improved model collaboration can strengthen our ability to project biomass supply, demand, and impacts. This in turn can aid in improving the information for policy‐makers and in taking better‐informed decisions.

Competing uses of biomass for energy and chemicals: implications for long‐term global CO2 mitigation potential

The demand for fossil fuels for non-energy purposes such as production of bulk chemicals is poorly understood. In this study we analyse data on non-energy demand and disaggregate it across key services or products. We construct a simulation model for the main products of non-energy use and project the global demand for primary fuels used as feedstocks and the resulting carbon emissions until 2100. The model is then applied to estimate the potential emission reductions by increased use of biomass, a more ambitious climate policy and advanced post-consumer waste management. We project that the global gross demand for feedstocks more than triples from 30 EJ in 2010 to over 100 EJ in 2100, mainly due to the increased demand for high value chemicals such as ethylene. Carbon emissions increase disproportionately (from 160 MtC per year in 2010 to over 650 MtC per year in 2100) due to greater use of coal, especially in ammonia and methanol production. If biomass is used, it can supply a large portion of the required primary energy and reduce carbon emissions by up to 20% in 2100 compared to the reference development. Climate policy can further reduce emissions by over 30%. Post-consumer waste management options such as recycling or incineration with energy recovery do not necessarily reduce energy demand or carbon emissions.

Mitigation of unwanted direct and indirect land-use change - an integrated approach illustrated for palm oil, pulpwood, rubber and rice production in North and East Kalimantan, Indonesia

Biomass is considered a low carbon source for various energy or chemical options. This paper assesses its different possible uses, the competition between these uses, and the implications for long‐term global energy demand and energy system emissions. A scenario analysis is performed using the TIMER energy system model. Under baseline conditions, 170 EJ yr−1 of secondary bioenergy is consumed in 2100 (approximately 18% of total secondary energy demand), used primarily in the transport, buildings and nonenergy (chemical production) sectors. This leads to a reduction of 9% of CO2 emissions compared to a counterfactual scenario where no bioenergy is used. Bioenergy can contribute up to 40% reduction in emissions at carbon taxes greater than 500/tC. As higher CO2 taxes are applied, bioenergy is increasingly diverted towards electricity generation. Results are more sensitive to assumptions about resource availability than technological parameters. To estimate the effectiveness of bioenergy in specific sectors, experiments are performed in which bioenergy is only allowed in one sector at a time. The results show that cross‐sectoral leakage and emissions from biomass conversion limit the total emission reduction possible in each sector. In terms of reducing emissions per unit of bioenergy use, we show that the use of bioelectricity is the most effective, especially when used with carbon capture and storage. However, this technology only penetrates at a high carbon price (>100/tC) and competition with transport fuels may limit its adoption.

GHG emissions and other environmental impacts of indirect land use change mitigation

The widespread production of cash crops can result in the decline of forests, peatlands, rice fields and local community land. Such unwanted land‐use and land‐cover (LULC) change can lead to decreased carbon stocks, diminished biodiversity, displaced communities and reduced local food production. In this study, we analysed to what extent four main commodities, namely, palm oil, pulpwood, rice and rubber, can be produced in North and East Kalimantan in Indonesia without such unwanted LULC change. We investigated the technical potential of four measures to mitigate unwanted LULC change between 2008 and 2020 under low, medium and high scenarios, referring to the intensities of the mitigation measures compared with those implemented in 2008. These measures are related to land sparing through (i) the improvements of yields, (ii) chain efficiencies, (iii) chain integration and (iv) the steering of any expansion of these commodities to suitable and available underutilised (potentially degraded) lands. Our analyses resulted in a land‐sparing potential of 0.4–1.2 Mha (i.e. 24–62% of the total land demand of the commodities) between 2008 and 2020, depending on the land‐use projection of the four commodities and the scenario for implementing the mitigation measures. Additional expansion on underutilised land is the most important mitigation measure (45–62% of the total potential), followed by yield improvements as the second most important mitigation measure (32–46% of the total potential). Our study shows that reconciling the production of palm oil, pulpwood, rice and rubber with the maintenance of existing agricultural lands, forests and peatlands is technically possible only (i) under a scenario of limited agricultural expansion, (ii) if responsible land zoning is applied and enforced and (iii) if the yields and chain efficiencies are strongly improved.

Bioethanol potential from miscanthus with low ILUC risk in the province of Lublin, Poland

The implementation of measures to increase productivity and resource efficiency in food and bioenergy chains as well as to more sustainably manage land use can significantly increase the biofuel production potential while limiting the risk of causing indirect land use change (ILUC). However, the application of these measures may influence the greenhouse gas (GHG) balance and other environmental impacts of agricultural and biofuel production. This study applies a novel, integrated approach to assess the environmental impacts of agricultural and biofuel production for three ILUC mitigation scenarios, representing a low, medium and high miscanthus‐based ethanol production potential, and for three agricultural intensification pathways in terms of sustainability in Lublin province in 2020. Generally, the ILUC mitigation scenarios attain lower net annual emissions compared to a baseline scenario that excludes ILUC mitigation and bioethanol production. However, the reduction potential significantly depends on the intensification pathway considered. For example, in the moderate ILUC mitigation scenario, the net annual GHG emissions in the case study are 2.3 MtCO2‐eq yr−1 (1.8 tCO2‐eq ha−1 yr−1) for conventional intensification and −0.8 MtCO2‐eq yr−1 (−0.6 tCO2‐eq ha−1 yr−1) for sustainable intensification, compared to 3.0 MtCO2‐eq yr−1 (2.3 tCO2‐eq ha−1 yr−1) in the baseline scenario. In addition, the intensification pathway is found to be more influential for the GHG balance than the ILUC mitigation scenario, indicating the importance of how agricultural intensification is implemented in practice. Furthermore, when the net emissions are included in the assessment of GHG emissions from bioenergy, the ILUC mitigation scenarios often abate GHG emissions compared to gasoline. But sustainable intensification is required to attain GHG abatement potentials of 90% or higher. A qualitative assessment of the impacts on biodiversity, water quantity and quality, soil quality and air quality also emphasizes the importance of sustainable intensification.

Greenhouse gas emission curves for advanced biofuel supply chains

Increasing production of biofuels has led to concerns about indirect land‐use change (ILUC). So far, significant efforts have been made to assess potential ILUC effects. But limited attention has been paid to strategies for reducing the extent of ILUC and controlling the type of LUC. This case study assesses five key ILUC mitigation measures to quantify the low‐ILUC‐risk production potential of miscanthus‐based bioethanol in Lublin province (Poland) in 2020. In 2020, a total area of 196 to 818 thousand hectare of agricultural land could be made available for biomass production by realizing above‐baseline yield developments (95–413 thousand ha), increased food chain efficiencies (9–30 thousand ha) and biofuel feedstock production on underutilized lands (92–375 thousand ha). However, a maximum 203–269 thousand hectare is considered legally available (not protected) and biophysically suitable for miscanthus production. The resulting low‐ILUC‐risk bioethanol production potential ranges from 12 to 35 PJ per year. The potential from this region alone is higher than the national Polish target for second‐generation bioethanol consumption of 9 PJ in 2020. Although the sustainable implementation potential may be lower, the province of Lublin could play a key role in achieving this target. This study shows that the mitigation or prevention of ILUC from bioenergy is only possible when an integrated perspective is adopted on the agricultural and bioenergy sectors. Governance and policies on planning and implementing ILUC mitigation are considered vital for realizing a significant bioenergy potential with low ILUC risk. One important aspect in this regard is monitoring the risk of ILUC and the implementation of ILUC mitigation measures. Key parameters for monitoring are land use, land cover and crop yields.