Advanced SQL-Database for bioenergy technologies - A catalogue for bio-resources, conversion technologies, energy carriers, and supply applications.

Bioenergy is a crucial element of the future energy system with wide range of applications in electricity, heat and transport. A major challenge for the analysis and optimisation of the bioenergy system is the degree of diversity and complexity compared to wind or solar energy. A coherent database for studying the role of bioenergy in the energy system needs to cover the different entities such as bio-resources, conversion procedures and process chains. Since there is no comprehensive data collection for bioenergy so far, we develop a SQLite database by merging several existing datasets and additional information. The resulting Bio-Energy Technology Database (BET.db) provides a consistent set of 141 feedstocks as well as energy carriers, 259 conversion technologies, and 134 energy supply concepts. The proof of concept within a bioenergy system modelling a wide range of technologies for the electricity, heat and transport sectors using the BENOPT model has been successful. By providing a one-stop-shop solution for techno-economic information about on the bioenergy nexus, this blind spot can be avoided for further investigations. The current stage of development is an intermediate prototype that will be developed into a more versatile and interactive web application later on.

Making the COVID-19 crisis a real opportunity for environmental sustainability.

An optimistic narrative has gained momentum during the first year of the pandemic: the COVID-19 crisis may have opened a window of opportunity to "rebuild better", to spur societal transitions towards environmental sustainability. In this comment, we review first evidence of individual and political changes made so far. Findings suggest that economies worldwide are not yet building back better. Against this background, we argue that a naïve opportunity narrative may even impair the progress of transitions towards environmental sustainability because it may render green recovery measures ineffective, costly, or infeasible. Based on these observations, we derive conditions for green recovery policies to succeed. They should consist of a policy mix combining well-targeted green subsidies with initiatives to price emissions and scrap environmentally harmful subsidies. Moreover, green recovery policies must be embedded into a narrative that avoids trading off environmental sustainability with other domains of sustainability-and rather highlights respective synergies that can be realized when recovering from the COVID-19 crisis.

How to identify suitable ways for the hydrothermal treatment of wet bio-waste? A critical review and methods proposal.

A considerable amount of wet biogenic residues and waste has no resource-efficient use in several European countries yet. Hydrothermal processes (HTP) seem to be promising for treating such biomass as they best work with substrates with 70% to 90% water content. However, thus far the suitability of HTP for this purpose has not been sufficiently evaluated, for which this work aims to identify suitable multi-criteria analysis (MCA) methods that can be used to identify promising ways for the hydrothermal treatment of wet bio-waste. A review on 31 recent MCA studies in bio-waste management was conducted with the aim of comparing them to methodological requirements for evaluating HTP. Furthermore, an MCA approach for HTP based on the review findings is proposed. Results show that no observed MCA method is directly transferable for assessing HTP, for which a customized approach combining the analytical hierarchy process and the technique for order preference by similarity to ideal solutions is proposed and preliminarily validated with literature data. These preliminary calculations indicate that hydrothermal gasification seems most promising under consideration of multiple criteria using the available average and exemplary data. However, needless to say there is still a long way to go to obtain the sufficient adequate data to validate and use the model appropriately, for which further studies are necessary to acquire more reliable data and to assess also future technology developments of HTP.

Cascade use indicators for selected biopolymers: Are we aiming for the right solutions in the design for recycling of bio-based polymers?

When surveying the trends and criteria for the design for recycling (DfR) of bio-based polymers, priorities appear to lie in energy recovery at the end of the product life of durable products, such as bio-based thermosets. Non-durable products made of thermoplastic polymers exhibit good properties for material recycling. The latter commonly enjoy growing material recycling quotas in countries that enforce a landfill ban. Quantitative and qualitative indicators are needed for characterizing progress in the development towards more recycling friendly bio-based polymers. This would enable the deficits in recycling bio-based plastics to be tracked and improved. The aim of this paper is to analyse the trends in the DfR of bio-based polymers and the constraints posed by the recycling infrastructure on plastic polymers from a systems perspective. This analysis produces recommendations on how life cycle assessment indicators can be introduced into the dialogue between designers and recyclers in order to promote DfR principles to enhance the cascading use of bio-based polymers within the bioeconomy, and to meet circular economy goals.

Pesticide runoff from energy crops: A threat to aquatic invertebrates?

The European Union aims to reach a 10% share of biofuels in the transport sector by 2020. The major burden is most likely to fall on already established annual energy crops such as rapeseed and cereals for the production of biodiesel and bioethanol, respectively. Annual energy crops are typically cultivated in intensive agricultural production systems, which require the application of pesticides. Agricultural pesticides can have adverse effects on aquatic invertebrates in adjacent streams. We assessed the relative ecological risk to aquatic invertebrates associated with the chemical pest management from six energy crops (maize, potato, sugar beet, winter barley, winter rapeseed, and winter wheat) as well as from mixed cultivation scenarios. The pesticide exposure related to energy crops and cultivation scenarios was estimated as surface runoff for 253 small stream sites in Central Germany using a GIS-based runoff potential model. The ecological risk for aquatic invertebrates, an important organism group for the functioning of stream ecosystems, was assessed using acute toxicity data (48-h LC50 values) of the crustacean Daphnia magna. We calculated the Ecological Risk from potential Pesticide Runoff (ERPR) for all three main groups of pesticides (herbicides, fungicides, and insecticides). Our findings suggest that the crops potato, sugar beet, and rapeseed pose a higher ecological risk to aquatic invertebrates than maize, barley, and wheat. As maize had by far the lowest ERPR values, from the perspective of pesticide pollution, its cultivation as substrate for the production of the gaseous biofuel biomethane may be preferable compared to the production of, for example, biodiesel from rapeseed.

Competition--supporting or preventing an increased use of bioenergy?

The intensified use of biomass as an energy source is an often-repeated goal of the German and European climate protection policy. Therefore, framework conditions have been created in recent years, which allow for a wider use of biomass within the energy system especially for a provision of electricity and fuels. Due to this policy, Germany, for example, has emerged as the leading producer of biogas from energy crops and fatty methyl ester (FAME) in Europe. However, due to the high energy price level, the use of biomass for heating purposes and as a renewable raw material have increased at the same time. To supply the obviously increased demand for biomass or biobased energy carriers cost efficiently, nationwide and to some extend even global markets are under development at present. As the demand for biomass is expected to continue to increase strongly, it is feared that an increasing competition with the use for food and fodder as well as a raw material might occur in the years to come. Against this background we have analyzed the competitions that can be expected, and the influence that they may have on the further expansion of the use of biomass for energy production. Experiences from Germany are provided exemplarily. Based on this, it is concluded that measures need to be taken to support an efficient and sustainable use of bioenergy in the future.