• Energy Research

Grasses, legumes and green plant wastes represent a ubiquitous feedstock for developing a bioeconomy in regions across Europe. These feedstocks are often an important source of ruminant feed, although much remains unused or underutilised. In addition to proteins, these materials are rich in fibres, sugars, minerals and other components that could also be used as inputs for bio-based product development. Green Biorefinery processes and initiatives are being developed to better capitalise on the potential of these feedstocks to produce sustainable food, feed, materials and energy in an integrated way. Such systems may support a more sustainable primary production sector, enable the valorisation of green waste streams, and provide new business models for farmers. This review presents the current developments in Green Biorefining, focusing on a broad feedstock and product base to include different models of Green Biorefinery. It demonstrates the potential and wide applicability of Green Biorefinery systems, the range of bio-based product opportunities and highlights the way forward for their broader implementation. While the potential for new products is extensive, quality control approval will be required prior to market entry.

The application of life cycle assessment (LCA) to biorefineries is a necessary step to estimate their environmental sustainability. This review explores contemporary LCA biorefinery studies, across different feedstock categories, to understand approaches in dealing with key methodological decisions which arise, including system boundaries, consequential or attributional approach, allocation, inventory data, land use changes, product end-of-life (EOL), biogenic carbon storage, impact assessment and use of uncertainty analysis. From an initial collection of 81 studies, 59 were included within the final analysis, comprising 22 studies which involved dedicated feed-stocks, 34 which involved residue feedstocks (including by-products and wastes), and a further 3 studies which involved multiple feedstocks derived from both dedicated and secondary sources. Many studies do not provide a comprehensive LCA assessment, often lacking detail on decisions taken, omitting key parts of the value chain, using generic data without uncertainty analyses, or omitting important impact categories. Only 28% of studies included some level of primary data, while 39% of studies did not undertake an uncertainty or sensitivity analysis. Just 8% of studies included data related to dLUC with a further 8% including iLUC, and only 14% of studies considering product end of life within their scope. The authors recommend more transparency in bio-refinery LCA, with justification of key methodological decisions. A full value-chain approach should be adopted, to fully assess burdens and opportunities for biogenic carbon storage. We also propose a more prospective approach, taking into account future use of renewable energy sources, and opportunities for increasing circularity within bio-based value chains

Global warming and climate change are imminent threats to the future of humankind. A shift from the current reliance on fossil fuels to renewable energy is key to mitigating the impacts of climate change. Biological raw materials and residues can play a key role in this transition through technologies such as anaerobic digestion. However, biological raw materials must also meet other existing food, feed and material needs. Green biorefinery is an innovative concept in which green biomass, such as grass, is processed to obtain a variety of protein products, value-added co-products and renewable energy, helping to meet many needs from a single source. In this study, an analysis has been conducted to understand the renewable energy potential of green biorefinery by-products and residues, including grass whey, de-FOS whey and press cake. Using anaerobic digestion, the biogas and biomethane potential of these samples have been analyzed. An analysis of the fertiliser potential of the resulting digestate by-products has also been undertaken. All the feedstocks tested were found to be suitable for biogas production with grass whey, the most suitable candidate with a biogas and biomethane production yield of 895.8 and 544.6 L/kg VS, respectively, followed by de-FOS whey and press cake (597.4/520.3 L/kg VS and 510.7/300.3 L/kg VS, respectively). The results show considerable potential for utilizing biorefinery by-products as a source for renewable energy production, even after several value-added products have been co-produced.

The bioeconomy can support Europe’s transition to a low-carbon economy and help to meet key international, European and member state sustainability targets through the provision of bio-based products and energy derived from sustainably sourced biomass. A successful implementation of a bio-based economy in Europe will, however, require a profound transformation of our production and consumption patterns. Consumer behavior will play a major role in supporting the successful transition to a bio-based economy. This paper uses a structured quantitative survey approach to gain an understanding of consumer perspectives in relation to bio-based products. Conducted among 18–75-year-old consumers in Ireland and the Netherlands, the study indicates that consumers in both countries have a relatively positive outlook regarding bio-based products, with Irish consumers showing a slightly more positive outlook. The study finds that a larger majority of Irish consumers would prefer buying bio-based products as opposed to fossil-based products, while Irish consumers also have a slightly more positive impression than Dutch consumers that their consumer choices can be beneficial for the environment.

Agriculture in Ireland is responsible for producing and exporting healthy, nutritional food pivotal for meeting the Sustainable Development Goals (SDGs) such as global food security, economic development and sustainable communities. However, the agricultural sector, dominated by a large bovine population, faces the challenge of reducing greenhouse gas (GHG) emissions to reach climate neutrality by 2050. The objective of the current study was to model the environmental and economic impact of simultaneously applying farm-level climate change mitigation strategies for a conventional grass-based dairy farm in Ireland. An average farm of 52 ha with a spring-calving herd of 93 was used as a reference scenario to create a business case. Partial budgeting was used to calculate the annual net benefit. A cradle-to-grave life cycle assessment (LCA) was used to model the reduction in GHG emissions, which was expressed as kg of carbon dioxide equivalent per kilogram of fat- and protein-corrected milk (kg CO2-eq/kg FPCM). The baseline for average emissions was 0.960 kg CO2-eq/kg FPCM. An average farm would reduce its annual emissions by 12% to 0.847 kg CO2-eq/kg FPCM in Scenario 1, where climate change mitigation strategies were applied on a minimal scale. For Scenario 2, the emissions are reduced by 36% to 0.614 kg CO2-eq/kg FPCM. In terms of annual savings on cash income, an increase of EUR 6634 and EUR 18,045 in net savings for the farm are realised in Scenarios 1 and 2, respectively. The business case provides evidence that farms can move towards climate neutrality while still remaining economically sustainable.

Microorganisms, such as fungi and bacteria, are crucial players in the production of enzymatic cocktails for biomass hydrolysis or the bioconversion of plant biomass into products with industrial relevance. The biotechnology industry can exploit lignocellulosic biomass for the production of high-value chemicals. The generation of biotechnological products from lignocellulosic feedstock presents several bottlenecks, including low efficiency of enzymatic hydrolysis, high cost of enzymes, and limitations on microbe metabolic performance. Genetic engineering offers a route for developing improved microbial strains for biotechnological applications in high-value product biosynthesis. Sugarcane bagasse, for example, is an agro-industrial waste that is abundantly produced in sugar and first-generation processing plants. Here, we review the potential conversion of its feedstock into relevant industrial products via microbial production and discuss the advances that have been made in improving strains for biotechnological applications.

The significant grasslands of Europe and its member states represents a significant feedstock opportunity for circular bioeconomy development. The development of green biorefineries (GBR), to supply protein for the feed industry from grass, could help many European member states to address significant deficits in protein availability and reduce imports. The current study assesses the environmental footprint of alternative GBR protein extraction techniques from grasses and legumes using life cycle assessment. The focus is on comparing feedstock and technology pathways that could displace soya bean imports. The study finds that leaf protein concentrate (LPC) produced from grass had an improved environmental performance when compared to soya bean meal (SBM), across the assessed feedstock (perennial ryegrass or grass-clover mixtures) and technology pathways (one-stage maceration versus multi-stage maceration). For example, in the case of Climate Change the emission intensity for LPC was 57–85 % lower per tonne of crude protein (CP) compared with SBM. Acidification burdens were 54–88 % lower, and Eutrophication: Freshwater burdens were 74–89 % lower. Some scenarios of GBR produced LPC with a larger Energy Resources: Non-Renewable burden than SBM, though this could be mitigated with higher renewable energy (biogas and wind energy) integration within the scenario. Grass-clover scenarios generally achieved a lower intensity of emissions compared to ryegrass scenarios, particularly in the category of Climate Change, where feedstock cultivation represented a significant contributor to impacts. Overall, GBR can produce high quality protein with a lower environmental burden than SBM, but choice of feedstock and system design are critical factors for overall environmental performance.