Bioenergy for climate change mitigation: Scale and sustainability

Abstract

Many global climate change mitigation pathways presented in IPCC assessment reports rely heavily on the deployment of bioenergy, often used in conjunction with carbon capture and storage. We review the literature on bioenergy use for climate change mitigation, including studies that use top‐down integrated assessment models or bottom‐up modelling, and studies that do not rely on modelling. We summarize the state of knowledge concerning potential co‐benefits and adverse side effects of bioenergy systems and discuss limitations of modelling studies used to analyse consequences of bioenergy expansion. The implications of bioenergy supply on mitigation and other sustainability criteria are context dependent and influenced by feedstock, management regime, climatic region, scale of deployment and how bioenergy alters energy systems and land use. Depending on previous land use, widespread deployment of monoculture plantations may contribute to mitigation but can cause negative impacts across a range of other sustainability criteria. Strategic integration of new biomass supply systems into existing agriculture and forest landscapes may result in less mitigation but can contribute positively to other sustainability objectives. There is considerable variation in evaluations of how sustainability challenges evolve as the scale of bioenergy deployment increases, due to limitations of existing models, and uncertainty over the future context with respect to the many variables that influence alternative uses of biomass and land. Integrative policies, coordinated institutions and improved governance mechanisms to enhance co‐benefits and minimize adverse side effects can reduce the risks of large‐scale deployment of bioenergy. Further, conservation and efficiency measures for energy, land and biomass can support greater flexibility in achieving climate change mitigation and adaptation.

The Production Gap Report 2021

“…for afforestation and biomass could lead to unsustainable levels of water use and pollution and pose additional sustainability risks for agriculture and food systems and biodiversity (Calvin et al, 2021;Fuss et al, 2014Fuss et al, , 2018Minx et al, 2018;Nemet et al, 2018;Robledo-Abad et al, 2017;Séférian et al, 2018;Smith et al, 2016Smith et al, , 2019. Consequently, we consider the production gap implied by the P4 scenario to also be implausible, at least on the basis of land requirements.…”

A Review between Climate Smart Agriculture Technology Objectives’ Synergies and Tradeoffs

“…Large-scale bioenergy production brings trade-offs, such as forest or water protection [38,39] (i.e., increases in food prices, which makes it a negative contribution to poor households). Agriculture intensification and improved fertility input efficiency, on the other hand, are not cost-effective for marginalized populations, for example, improved cultivars, improved animal breeds, and irrigation equipment [39].…”

“…National policy proposals and strategies are essential within that framework for resolving sustainability issues associated with climate actions, but national research is still limited and unknown. Furthermore, most countries heavily subsidize fuel, which creates a huge disincentive for farmers to use water and energy properly [38,40]. Moving forward, we must change this situation through strategies such as water policy, water tariffs, and reduced fuel subsidies, while also developing a reliable social safety net that will not push millions into poverty and jeopardize the country's stability [41].…”

“…Furthermore, the timing of climate change mitigation and policy instrument deployment can alter the multi-sectoral impacts. According to [2] and [38] evaluated the trade-offs in meeting climate targets under five possible bioenergy and land-use strategies, finding that deforestation would be common if no complementing land policy was implemented.…”

Integration of biodiesel internal combustion engines and transcritical organic Rankine cycles for waste‐heat recovery in small‐scale applications

“…To this purpose, it is fundamental to exploit residual and waste materials to fulfil sustainability criteria and mitigate gas emissions. 26,27 The residues adoption as feedstocks increases energy supply security, 28,29 promotes a low-carbon circular economy, 30,31 avoids competition with the agricultural sector, 32,33 and prevents land-use change. 25,34 From this perspective, liquid bio-based resources offer several advantages for electricity and heating production compared to other bioenergy owing to the high energy density, effective transport, and convenient storage.…”