From environmental nuisance to environmental opportunity: housefly larvae convert waste to livestock feed
Zanten, H.H.E. van; Mollenhorst, H. ; Oonincx, D.G.A.B. ; Bikker, P. ; Meerburg, B.G. ; Boer, I.J.M. de - \ 2015
Journal of Cleaner Production 102 (2015). - ISSN 0959-6526 - p. 362 - 369.
life-cycle perspective - bio-energy - food - consequences - variability - digestion - scenarios - amazon - manure - land
The livestock sector is in urgent need for more sustainable feed sources, because of the increased demand for animal-source food and the already high environmental costs associated with it. Recent developments indicate environmental benefits of rearing insects for livestock feed, suggesting that insect-based feed might become an important alternative feed source in the coming years. So far, however, this potential environmental benefit of waste-fed insects is unknown. This study, therefore, explores the environmental impact of using larvae of the common housefly grown on poultry manure and food waste as livestock feed. Data were provided by a laboratory plant in the Netherlands aiming to design an industrial plant for rearing housefly larvae. Production of 1 ton dry matter of larvae meal directly resulted in a global warming potential of 770 kg CO2 equivalents, an energy use of 9329 MJ and a land use of 32 m2, caused by use of water, electricity, and feed for flies, eggs and larvae. Production of larvae meal, however, also has indirect environmental consequences. Food waste, for example, was originally used for production of bio-energy. Accounting for these indirect consequences implies, e.g., including the environmental impact of production of energy needed to replace the original bio-energy function of food waste. Assuming, furthermore, that 1 ton of larvae meal replaced 0.5 ton of fishmeal and 0.5 ton of soybean meal, the production of 1 ton larvae meal reduced land use (1713 m2), but increased energy use (21,342 MJ) and consequently global warming potential (1959 kg CO2-eq). Results of this study will enhance a transparent societal and political debate about future options and limitations of larvae meal as livestock feed. Results of the indirect environmental impact, however, are situation specific, e.g. in this study food waste was used for anaerobic digestion. In case food waste would have been used for, e.g., composting, the energy use and related emission of greenhouse gases might decrease. Furthermore, the industrial process to acquire housefly larvae meal is still advancing, which also offers potential to reduce energy use and related emissions. Eventually, land scarcity will increase further, whereas opportunities exist to reduce energy use by, e.g., technical innovations or an increased use of solar or wind energy. Larvae meal production, therefore, has potential to reduce the environmental impact of the livestock sector.
The policy and practice of sustainable biofuels: Between global frameworks and local heterogeneity. The case of food security in Mozambique
Schut, M. ; Florin, M.J. - \ 2015
Biomass and Bioenergy 72 (2015). - ISSN 0961-9534 - p. 123 - 135.
bio-energy - governance - ethanol - certification - countries - markets - trade
This study explores the relationship between different biofuel production systems, the context in which they operate, and the extent to which various types of frameworks and schemes are able to monitor and promote their sustainability. The paper refers to the European Union Renewable Energy Directive and two international certification schemes (Roundtable on Sustainable Biofuels and NTA 8080/81) that can provide a ‘licence to sell’ biofuels on the EU market, and to the Mozambican policy framework for sustainable biofuels that provides a ‘licence to produce’ biomass for biofuels in Mozambique. Food security is used as a case study, and the food security impacts of two agro-industrial and two smallholder biofuel projects in Mozambique are described and analysed. The sustainability frameworks and schemes used in this study are able to address some, but not all, of the heterogeneity between and within different biofuel production systems. The emphasis is on monitoring agro-industrial projects while smallholder projects tend to slip through the net even when their negative impacts are evident. We conclude that globally applicable sustainability principles are useful, however, they should be operationalised at local or production system levels. This approach will support balancing between global frameworks and local heterogeneity.
Model collaboration for the improved assessment of biomass supply, demand, and impacts
Wicke, B. ; Hilst, F. van der; Daioglou, V. ; Banse, M. ; Beringer, T. ; Gerssen-Gondelach, S. ; Heijnen, S. ; Karssenberg, D. ; Laborde, D. ; Lippe, M. ; Meijl, H. van; Nassar, A. ; Powell, J.P. ; Prins, A.G. ; Rose, S.N.K. ; Smeets, E.M.W. ; Stehfest, E. ; Tyner, W.E. ; Verstegen, J.A. ; Valin, H. ; Vuuren, D.P. van; Yeh, S. ; Faaij, A.P.C. - \ 2015
Global change biology Bioenergy 7 (2015)3. - ISSN 1757-1693 - p. 422 - 437.
land-use change - global agricultural markets - greenhouse-gas emissions - eu biofuel policies - bioenergy production - united-states - energy crops - trade-offs - bio-energy - ethanol
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.
Assessing environmental consequences of using co-products in animal feed
Zanten, H.H.E. van; Mollenhorst, H. ; Vries, J.W. de; Middelaar, C.E. van; Kernebeek, H.R.J. van; Boer, I.J.M. de - \ 2014
The International Journal of Life Cycle Assessment 19 (2014)1. - ISSN 0948-3349 - p. 79 - 88.
bio-energy - digestion - impact - rumen - perspective - absorption - manure - tract - model
The livestock sector has a major impact on the environment. This environmental impact may be reduced by feeding agricultural co-products (e.g. beet tails) to livestock, as this transforms inedible products for humans into edible products, e.g. pork or beef. Nevertheless, co-products have different applications such as bioenergy production. Based on a framework we developed, we assessed environmental consequences of using co-products in diets of livestock, including the alternative application of that co-product. We performed a consequential life cycle assessment, regarding greenhouse gas emissions (including emissions related to land use change) and land use, for two case studies. Case 1 includes increasing the use of wheat middlings in diets of dairy cattle at the expense of using it in diets of pigs. The decreased use of wheat middlings in diets of pigs was substituted with barley, the marginal product. Case 2 includes increasing the use of beet tails in diets of dairy cattle at the expense of using it to produce bioenergy. During the production of biogas, electricity, heat and digestate (that is used as organic fertilizer) were produced. The decrease of electricity and heat was substituted with fossil fuel, and digestate was substituted with artificial fertilizer. Using wheat middlings in diets of dairy cattle instead of using it in diets of pigs resulted in a reduction of 329 kg CO2 eq per ton wheat middlings and a decrease of 169 m(2) land. Using beet tails in diets of dairy cattle instead of using it as a substrate for anaerobic digestion resulted in a decrease of 239 kg CO2 eq per ton beet tails and a decrease of 154 m(2) land. Emissions regarding land use change contributed significantly in both cases but had a high uncertainty factor, +/- 170 ton CO2 ha(-1). Excluding emissions from land use change resulted in a decrease of 9 kg CO2 eq for case 1 'wheat middlings' and an increase of 50 kg CO2 eq for case 2 'beet tails'. Assessing the use of co-products in the livestock sector is of importance because shifting its application can reduce the environmental impact of the livestock sector. A correct assessment of the environmental consequences of using co-products in animal feed should also include potential changes in impacts outside the livestock sector, such as the impact in the bioenergy sector.
What drives sustainable biofuels? A review of indicator assessments of biofuel production systems involving smallholder farmer
Florin, M.J. ; Ven, G.W.J. van de; Ittersum, M.K. van - \ 2014
Environmental Science & Policy 37 (2014). - ISSN 1462-9011 - p. 142 - 157.
soil fertility decline - land-use change - food security - jatropha plantations - developing-countries - rural livelihoods - farming systems - tamil-nadu - bio-energy - water-use
The contribution of biofuel production to sustainable development in rural areas requires policy and practice that understands the opportunities and risks faced by smallholder farmers. Potential opportunities for smallholders include access to markets, access to employment, local infrastructure developments and spill over effects such as new agronomic knowledge. Potential threats include loss of land entitlements, social exclusion, environmental degradation, dependency upon the biofuel industry and diminished food security. Although a multitude of issues is acknowledged, many studies are focused on specific issues and knowledge remains fragmented. Further, much of the indicator-based literature does not acknowledge the importance of case-specificity nor the link between the processes and circumstances that drive indicator results. This article reviews indicator assessments of biofuel production involving smallholders and highlights the importance of holistically considering a range of social, economic and environmental criteria. Further this review stresses the need to link drivers with indicators. Drivers include decisions and circumstances of a biophysical, socio-economic and governance nature with relevance at field, farm and higher levels. The link between drivers and indicators is crucial to justify indicators and to identify the scope for policy to influence progress against indicators. A conceptual model is provided that summarises important processes determining sustainability of biofuel production involving smallholders. This model can also be used as a starting point for more detailed analysis capturing and quantifying relationships between specific drivers and indicators on a case-by-case basis. This type of analysis is particularly valuable in regions where biofuel policy and developments are unfolding and multiple stakeholders (e.g. smallholders, companies, NGOs and governments) are involved. We highlight that regulation and certification of biofuel production often needs to be complemented with improvements in governance structures and, that policy targeting smallholder involvement with biofuel production should account for a diversity of smallholder characteristics
Harmonising bioenergy resource potentials-Methodological lessons from review of state of the art bioenergy potential assessments
Batidzirai, B. ; Smeets, E.M.W. ; Faaij, A.P.C. - \ 2012
Renewable and Sustainable Energy Reviews 16 (2012)9. - ISSN 1364-0321 - p. 6598 - 6630.
land-use scenarios - plantation biomass resources - climate-change - carbon sequestration - greenhouse-gas - bio-energy - water-use - sustainable bioenergy - spatial-distribution - integrated approach
Published estimates of the potential of bioenergy vary widely, mainly due to the heterogeneity of methodologies, assumptions and datasets employed. These discrepancies are confusing for policy and it is thus important to have scientific clarity on the basis of the assessment outcomes. Such clear insights can enable harmonisation of the different assessments. This review explores current state of the art approaches and methodologies used in bioenergy assessments, and identifies key elements that are critical determinants of bioenergy potentials. We apply the lessons learnt from the review exercise to compare and harmonise a selected set of country based bioenergy potential studies, and provide recommendations for conducting more comprehensive assessments. Depending on scenario assumptions, the harmonised technical biomass potential estimates up to 2030 in the selected countries range from 5,2 to 27.3 EJ in China, 1.1 to 18.8 EJ in India, 2.0 to 10.9 EJ in Indonesia, 1.6 to 7.0 EJ in Mozambique and 9.3 to 23.5 EJ in the US. From the review, we observed that generally, current studies do not cover all the basic (sustainability) elements expected in an ideal bioenergy assessment and there are marked differences in the level of parametric detail and methodological transparency between studies. Land availability and suitability lack spatial detail and especially degraded and marginal lands are poorly evaluated. Competition for water resources is hardly taken into account and biomass yields are based mostly on crude ecological zoning criteria. A few studies take into account improvements in management of agricultural and forestry production systems, but the underlying assumptions are hardly discussed. Competition for biomass resources among the various applications is crudely analysed in most studies and key assumptions such as demographic dynamics, biodiversity protection criteria, etc. are not explicitly discussed. To facilitate more comprehensive bioenergy assessments, we recommend an integrated analytical framework that includes all the key factors, employs high resolution geo-referenced datasets and accounts for potential feedback effects.