Ecological impacts and limits of biomass use: a critical review

© 2020, Springer-Verlag GmbH Germany, part of Springer Nature. Conventional biomass sources have been widely exploited for several end uses (mostly food, feed, fuel and chemicals). More unconventional sources are continually being sought for meeting the growing planetary demands for biomass materials. Biofuels are already commercially produced in many countries and are becoming mainstream. The role of biorefineries for production of chemicals is also on the rise. Plant biomass is the primary source of food for all multicellular living organisms. Primary production remains a key link in the chain of life support on planet Earth. Is there enough for all? What new strategies (or technologies) are available or promising for providing plant biomass in a safe and sustainable way? What are the potential impacts (footprints and efficiencies) of such strategies? What can be the limiting factors—land, water, energy and nutrients? What might be the limits for specific regions (OECD vs. non-OECD, advanced vs. developing, dry and warm vs. wet and cool, etc.). In this paper, we provided answers to these questions by critically reviewing the pros and cons associated with current and future production and use pathways for biomass. We conclude that in many cases, the jury is still out, and we cannot come to a solid verdict about the future of biomass production and use

Towards a more holistic sustainability assessment framework for agro-bioenergy systems — A review

© 2016 Elsevier Inc. The use of life cycle assessment (LCA) as a sustainability assessment tool for agro-bioenergy system usually has an industrial agriculture bias. Furthermore, LCA generally has often been criticized for being a decision maker tool which may not consider decision takers perceptions. They are lacking in spatial and temporal depth, and unable to assess sufficiently some environmental impact categories such as biodiversity, land use etc. and most economic and social impact categories, e.g. food security, water security, energy security. This study explored tools, methodologies and frameworks that can be deployed individually, as well as in combination with each other for bridging these methodological gaps in application to agro-bioenergy systems. Integrating agronomic options, e.g. alternative farm power, tillage, seed sowing options, fertilizer, pesticide, irrigation into the boundaries of LCAs for agro-bioenergy systems will not only provide an alternative agro-ecological perspective to previous LCAs, but will also lead to the derivation of indicators for assessment of some social and economic impact categories. Deploying life cycle thinking approaches such as energy return on energy invested-EROEI, human appropriation of net primary production-HANPP, net greenhouse gas or carbon balance-NCB, water footprint individually and in combination with each other will also lead to further derivation of indicators suitable for assessing relevant environmental, social and economic impact categories. Also, applying spatio-temporal simulation models has a potential for improving the spatial and temporal depths of LCA analysis

Bioenergy from low-intensity agricultural systems: An energy efficiency analysis

In light of possible future restrictions on the use of fossil fuel, due to climate change obligations and continuous depletion of global fossil fuel reserves, the search for alternative renewable energy sources is expected to be an issue of great concern for policy stakeholders. This study assessed the feasibility of bioenergy production under relatively low-intensity conservative, eco-agricultural settings (as opposed to those produced under high-intensity, fossil fuel based industrialized agriculture). Estimates of the net energy gain (NEG) and the energy return on energy invested (EROEI) obtained from a life cycle inventory of the energy inputs and outputs involved reveal that the energy efficiency of bioenergy produced in low-intensity eco-agricultural systems could be as much as much as 448.5-488.3 GJ·ha-1 of NEG and an EROEI of 5.4-5.9 for maize ethanol production systems, and as much as 155.0-283.9 GJ·ha-1 of NEG and an EROEI of 14.7-22.4 for maize biogas production systems. This is substantially higher than for industrialized agriculture with a NEG of 2.8-52.5 GJ·ha-1 and an EROEI of 1.2-1.7 for maize ethanol production systems, as well as a NEG of 59.3-188.7 GJ·ha-1 and an EROEI of 2.2-10.2 for maize biogas production systems. Bioenergy produced in low-intensity eco-agricultural systems could therefore be an important source of energy with immense net benefits for local and regional end-users, provided a more efficient use of the co-products is ensured