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Bioenergy deployment offers significant potential for climate change mitigation, but also carries considerable risks. In this review, we bring together perspectives of various communities involved in the research and regulation of bioenergy deployment in the context of climate change mitigation: Land‐use and energy experts, land‐use and integrated assessment modelers, human geographers, ecosystem researchers, climate scientists and two different strands of life‐cycle assessment experts. We summarize technological options, outline the state‐of‐the‐art knowledge on various climate effects, provide an update on estimates of technical resource potential and comprehensively identify sustainability effects. Cellulosic feedstocks, increased end‐use efficiency, improved land carbon‐stock management and residue use, and, when fully developed, BECCS appear as the most promising options, depending on development costs, implementation, learning, and risk management. Combined heat and power, efficient biomass cookstoves and small‐scale power generation for rural areas can help to promote energy access and sustainable development, along with reduced emissions. We estimate the sustainable technical potential as up to 100 EJ: high agreement; 100–300 EJ: medium agreement; above 300 EJ: low agreement. Stabilization scenarios indicate that bioenergy may supply from 10 to 245 EJ yr−1 to global primary energy supply by 2050. Models indicate that, if technological and governance preconditions are met, large‐scale deployment (>200 EJ), together with BECCS, could help to keep global warming below 2° degrees of preindustrial levels; but such high deployment of land‐intensive bioenergy feedstocks could also lead to detrimental climate effects, negatively impact ecosystems, biodiversity and livelihoods. The integration of bioenergy systems into agriculture and forest landscapes can improve land and water use efficiency and help address concerns about environmental impacts. We conclude that the high variability in pathways, uncertainties in technological development and ambiguity in political decision render forecasts on deployment levels and climate effects very difficult. However, uncertainty about projections should not preclude pursuing beneficial bioenergy options.

Despite increasing acknowledgement of the diversity and different approaches at play in research on sustainability transitions, systematic comparisons of these approaches are scarce. This is a problem for sustainability research, as the coexistence of multiple approaches to sustainability in the absence of an overarching comparative vocabulary may result in disparate and potentially incommensurable assumptions affecting the analysis, implementation, and impact of sustainability transitions. By means of a review and conceptual investigation, we develop a conceptual model for comparing multiple and diverse sustainability approaches. Investigating both the descriptive (stationary) and actionable elements of sustainability, we create a comparative space based on distinguishable parameters shared among sampled sustainability approaches as empirical literature-based units: (1) from instrumentalist to intrinsic valuations of nature; and (2) from holistic to particularistic system considerations. Using a vector-based method to represent a sustainability approach, we systematically compare various perceptions of sustainability problems and solutions, thereby allowing us to characterize different movements towards imagined sustainable futures.

The transition toward circular bio-economy models in the dairy sector demands innovative strategies to valorize whey, a nutrient-rich byproduct often discarded as waste. This study analyzes four circular business models adopted by Kenyan dairy processors: (i) ricotta cheese production, (ii) whey-based yogurt drinks, (iii) fruit-blended whey smoothies, and (iv) whey protein concentrate (WPC) recovery. Using a mixed-methods approach combining case studies of ten processors, stakeholder interviews, and EcoCanvas business model analysis, the study reveals that only 0.45% of the 976,055 L of whey generated weekly is valorized. Ricotta production emerged as the most accessible and cost-effective pathway, while smoothies and yogurt offer nutritional value but face market penetration challenges. WPC recovery, though capital-intensive, presents opportunities for import substitution if processors collaborate to aggregate whey volumes. Theoretically, the study integrates Circular Economy (CE), Business Model Innovation (BMI), and Resource-Based View (RBV) frameworks to explain inter-processor differences in adoption, showing how firm capabilities, external enablers, and systemic reconfiguration interact to drive circularity. Practically, the findings inform policy and industry efforts to enhance waste-to-value transitions in developing dairy economies. Key limitations include a small sample size ( n  = 10), reliance on self-reported data, and a focus on cheese-producing processors. Future research should investigate cooperative valorization models, consumer demand for whey-based products, and lifecycle assessments of environmental outcomes. By addressing structural and institutional barriers, Kenya’s dairy sector can unlock significant environmental, nutritional, and economic benefits through scalable whey valorization strategies.

Reconciling the aims of feeding an ever more demanding human population and conserving biodiversity is a difficult challenge. Here, we explore potential solutions by assessing whether land sparing (farming for high yield, potentially enabling the protection of non-farmland habitat), land sharing (lower yielding farming with more biodiversity within farmland) or a mixed strategy would result in better bird conservation outcomes for a specified level of agricultural production. We surveyed forest and farmland study areas in southern Uganda, measuring the population density of 256 bird species and agricultural yield: food energy and gross income. Parametric non-linear functions relating density to yield were fitted. Species were identified as \"winners\" (total population size always at least as great with agriculture present as without it) or \"losers\" (total population sometimes or always reduced with agriculture present) for a range of targets for total agricultural production. For each target we determined whether each species would be predicted to have a higher total population with land sparing, land sharing or with any intermediate level of sparing at an intermediate yield. We found that most species were expected to have their highest total populations with land sparing, particularly loser species and species with small global range sizes. Hence, more species would benefit from high-yield farming if used as part of a strategy to reduce forest loss than from low-yield farming and land sharing, as has been found in Ghana and India in a previous study. We caution against advocacy for high-yield farming alone as a means to deliver land sparing if it is done without strong protection for natural habitats, other ecosystem services and social welfare. Instead, we suggest that conservationists explore how conservation and agricultural policies can be better integrated to deliver land sparing by, for example, combining land-use planning and agronomic support for small farmers.

A zero-emission pathway for the Nordic and Baltic region in Europe is described based on the comprehensive policy and scenario analyses, accompanied by energy system modelling. The analyses show that a least-cost strategy would massively employ renewable energy, particularly in the power sector. Through strong coupling across energy sectors and countries, electricity would play a central role in the decarbonization of the main energy sectors. In particular power-to-heat conversion, where heat storage appears important in addition to existing hydropower. Technical and regulatory barriers in front of increased sector coupling and flexibility were identified, and policy measures are proposed to overcome these. In addition to a high carbon price, dynamic tariffs and taxation of electricity would be important to allow market signals for flexibility to reach end-users. A stronger power transmission connection from the Nordics to the mainland-Europe and the United Kingdom would be beneficial for the emission reductions and renewable energy use. The transition pathway analysis points out socio-technical issues such as social acceptance of large-scale new infrastructures (e.g., wind, cables). The energy system optimizations indicate that most of the investments needed for the zero-emission pathway until 2050 would take place already by 2030.

Integrated assessment models suggest that the large-scale deployment of bioenergy could contribute to ambitious climate change mitigation efforts. However, such a shift would intensify the global competition for land, with possible consequences for 1.5 billion smallholder livelihoods that these models do not consider. Maintaining and enhancing robust livelihoods upon bioenergy deployment is an equally important sustainability goal that warrants greater attention. The social implications of biofuel production are complex, varied and place-specific, difficult to model, operationalize and quantify. However, a rapidly developing body of social science literature is advancing the understanding of these interactions. In this letter we link human geography research on the interaction between biofuel crops and livelihoods in developing countries to integrated assessments on biofuels. We review case-study research focused on first-generation biofuel crops to demonstrate that food, income, land and other assets such as health are key livelihood dimensions that can be impacted by such crops and we highlight how place-specific and global dynamics influence both aggregate and distributional outcomes across these livelihood dimensions. We argue that place-specific production models and land tenure regimes mediate livelihood outcomes, which are also in turn affected by global and regional markets and their resulting equilibrium dynamics. The place-specific perspective suggests that distributional consequences are a crucial complement to aggregate outcomes; this has not been given enough weight in comprehensive assessments to date. By narrowing the gap between place-specific case studies and global models, our discussion offers a route towards integrating livelihood and equity considerations into scenarios of future bioenergy deployment, thus contributing to a key challenge in sustainability sciences.

This paper evaluates how policy shaped the emergence of electric mobility in three countries, Norway, the Netherlands and Denmark, between 2010 and 2015. Whereas previous studies have looked at the effects of separate policy instruments, this paper gives insights in the interaction effects of instruments on the diffusion of battery electric cars between five policy areas. Based on analysis of synergetic, contradictory and pre-conditional effects, we find that an effective policy mix includes: fiscal incentives that mirror the actual carbon footprint of the respective vehicles; non-fiscal demand-side incentives; centrally financed and/or coordinated charging infrastructure; clarity regarding the choice of technology that will be supported. Moreover, development of a domestic, e-mobility-related industry and a high share of renewable energy strengthens the legitimization of e-mobility support. The findings help designing policy mixes in the transition to electric mobility.

The Danish “Klima 2020” plan sets an ambitious target for the complete phasing-out of fossil fuels by 2050. The Danish energy sector currently accounts for 40% of national CO 2 emissions. Based on an extended Farrell input distance function that accounts for CO 2 as an undesirable output, we estimate the environmental productivity of individual generator units based on a panel data set for the period 1998 to 2011 that includes virtually all fuel-fired generator units in Denmark. We further decompose total environmental energy conversion productivity into conversion efficiency, best conversion practice ratio, and conversion scale efficiency and use a global Malmquist index to calculate the yearly changes. By applying time series clustering, we can identify high, middle, and low performance groups of generator units in a dynamic setting. Our results indicate that the sectoral productivity only slightly increased over the fourteen years. Furthermore, we find that there is no overall high achiever group, but that the ranking, although time consistent, varies between the different productivity measures. However, we identify steam turbines and combustion engines for combined heat and power production as potential high performers, while combustion engines that only produce electricity are clearly low performers.

Background Energy systems are currently undergoing fundamental transformations, with several possible energy futures emerging, including various decentralised ones. However, transformations are characterised by uncertainty, and it is difficult to assess the sustainability of these different energy futures. There is a danger that premature choices could lead to lock-ins to sub-optimal pathways as seen from a broad sustainability perspective. This paper explores the role of potential lock-ins on the pathways towards emerging configurations of decentralised, carbon-neutral energy systems. Our analysis draws on four emerging ideal-type decentralisation configurations of ‘energy futures’ (individual system optimisation, individual autonomy, collective system optimisation, and collective autonomy) and the institutional, actor and technological preconditions required for them to become dominant forms of energy system organisation. Results We developed a forward-looking, ex-ante approach to identify emergent lock-ins that may be created along the transition pathways. Conclusions These new lock-ins have implications for the sustainability of decentralised energy futures and how such sustainability should be assessed. Such an analysis can inform sustainable energy policies, helping to keep different options open and to avoid a premature lock-in to potentially sub-optimal socio-technical energy configurations.

The possibility of using bioenergy as a climate change mitigation measure has sparked a discussion of whether and how bioenergy production contributes to sustainable development. We undertook a systematic review of the scientific literature to illuminate this relationship and found a limited scientific basis for policymaking. Our results indicate that knowledge on the sustainable development impacts of bioenergy production is concentrated in a few well‐studied countries, focuses on environmental and economic impacts, and mostly relates to dedicated agricultural biomass plantations. The scope and methodological approaches in studies differ widely and only a small share of the studies sufficiently reports on context and/or baseline conditions, which makes it difficult to get a general understanding of the attribution of impacts. Nevertheless, we identified regional patterns of positive or negative impacts for all categories – environmental, economic, institutional, social and technological. In general, economic and technological impacts were more frequently reported as positive, while social and environmental impacts were more frequently reported as negative (with the exception of impacts on direct substitution of GHG emission from fossil fuel). More focused and transparent research is needed to validate these patterns and develop a strong science underpinning for establishing policies and governance agreements that prevent/mitigate negative and promote positive impacts from bioenergy production.