• Energy Research
• 12. Responsible consumption close
• IT close
• Journal of Cleaner Production close

It is easy to predict that in the coming years in Europe biodiesel will play an increasingly important role in the transport sector. The European Commission has set at 10% by 2020 the proportion that biofuels should represent in total fuel used in transport and biodiesel is currently the most widely used biofuel in the European Union. The most common way to produce biodiesel is through transesterification of vegetable oils with methanol; glycerol is the main co-product. Although glycerol has many industrial applications, increased production of biodiesel could make complete market placement of this chemical difficult. In this context, increasing interest is paid towards different methods of biodiesel production that provide alternative co-products. This article offers a “cradle to gate” evaluation of potential environmental impacts caused by an innovative process for the production of DMC-BioD, an alternative biofuel to biodiesel which does not involve the production of glycerol. Transesterification of soybean oil with dimethyl carbonate to obtain DMC-BioD has been modelled with the aid of the Chemical Process Simulation software Aspen HYSYS® that produced the material and energy balances and the preliminary sizing of the process units. Results have been also compared with background information from database on the production of conventional biodiesel from soybean oil and of fossil diesel. The study suggests that DMC-BioD can be an interesting route for the production of biofuels from an environmental point of view. Compared to fossil diesel, GHG (Greenhouse gases) emissions can be decreased, although trade-offs are registered in other environmental categories. In any case, future investigation is needed in order to understand and optimize its environmental profile through the entire life cycle and possibly bring its production to a commercial scale. This preliminary analysis of potential environmental impacts provides useful information to continue the testing and scale-up phases and to improve the environmental performances of the process.

Abstract The installation of infrastructures for carbon capture, transport, and storage to tackle the problem of CO2 emissions from European power plants and carbon intensive industries, is of strategic importance to reach future greenhouse gases reduction targets. However, the public reaction to the deployment of these technologies is still uncertain, and opposition may result in either cancellations or delays. This article provides quantitative insights into how social acceptance affects the design of a European CO2 infrastructure. A multi-objective mixed integer linear programming model is developed to optimise the design the entire supply chain, by simultaneously addressing the minimisation of the costs to install and operate the infrastructure and the maximisation of its community acceptance. The goal is to provide optimal supply chains in terms of costs, whilst considering the social behaviour of inhabitants towards the installation and operation of either CO2 pipelines or injection wells. Results demonstrate how the methodology may be exploited to assess the response of local communities and identify design strategies aiming at a trade-off between economic objectives and social acceptance. Although the maximisation of social acceptance leads to a +34% increase in costs with respect to the economic optimum, it is shown that an intermediate solution between the two objectives (i.e., economics against acceptance) entails a just slight increase of +8% with respect to the cost of the best economic configuration.

Abstract Offshore cultivation of seaweed provides an innovative feedstock for biobased products supporting blue growth in northern Europe. This paper analyzes two alternative exploitation pathways: energy and protein production. The first pathway is based on anaerobic digestion of seaweed which is converted into biogas, for production of electricity and heat, and digestate, used as fertilizer; the second pathway uses seaweed hydrolysate as a substrate for cultivation of heterotrophic microalgae. As a result the seaweed sugars are consumed while new proteins are produced enhancing the total output. We performed a comparative Life Cycle Assessment of five scenarios identifying the critical features affecting resource efficiency and environmental performance of the systems with the aim of providing decision support for the design of future industrial scale production processes. The results show that all scenarios provide environmental benefits in terms of mitigation of climate change, with biogas production from dried Laminaria digitata being the most favorable scenario, quantified as −18.7*10 2 kg CO 2 eq./ha. This scenario presents also the lowest consumption of total cumulative energy demand, 1.7*10 4 MJ/ha, and even resulting in a net reduction of the fossil energy fraction, −1.9*10 4 MJ/ha compared to a situation without seaweed cultivation. All scenarios provide mitigation of marine eutrophication thanks to bioextraction of nitrogen and phosphorus during seaweed growth. The material consumption for seeded lines has 2–20 times higher impact on human toxicity (cancer) than the reduction achieved by energy and protein substitution. However, minor changes in cultivation design, i.e. use of stones instead of iron as ballast to weight the seeded lines, dramatically reduces human toxicity (cancer). Externalities from the use of digestate as fertilizer affect human toxicity (non-cancer) due to transfer of arsenic from aquatic environment to agricultural soil. However concentration of heavy metals in digestate does not exceed the limit established by Danish regulation. The assessment identifies seaweed productivity as the key parameter to further improve the performance of the production systems which are a promising service provider of environmental restoration and climate change mitigation.

Abstract In this study, Solar Energy Demand (SED), Cumulative Exergy Extraction from the Natural Environment (CEENE), and LCA-ReCiPe 2016 (using both midpoint and endpoint modeling) life cycle impact assessment methods has been used to assess the performance of hydrogen (H2) production with renewable and non-renewable electricity sources via high-temperature Solid Oxide Electrolysis Cells. The analysis identified most relevant impact categories, life cycle stages, and processes, both from a thermodynamic and an environmental viewpoint. Electrolysis with non-renewable energy is characterized by the greatest environmental burdens, however, renewable energy systems also have considerable environmental impacts, some of which are significant. While no perfect electricity source exists, a growing portion of the renewable-based electricity production in the grid mix is an attractive option to lower environmental impacts of H2 production. Irrespective of the evaluation method, the contribution analysis from different life-cycle stages shows and confirm that the major contributor to the environmental burdens is the electricity supply. The manufacturing stage has high relevance for mineral and metal resources and toxicity-related impacts. Calculations of grid-based electrolysis life cycle environmental impacts in some European countries showed that significant variations. For example, global warming potential per kgH2 produced vary between 3.31 and 48.24 kgCO2. Trade-off analysis between the midpoint and endpoint indicators revealed that water consumption, global warming, and particulate matter formation, play a major role in the ranking of electricity supply options. The findings suggest that all potential impacts both at the midpoint and endpoint level should be considered to ensure robust results of the LCA evaluation, a fair comparison between pathways towards more transparent and evidence-based decisions. Towards that end, a further country site-specific assessment with optimization strategies and integration of traditional LCA with resource accounting (thermodynamic metrics) will need to be developed to explore additional valuable insights towards sustainable electrolytic H2 production systems.

In the last years, the circular economy (CE) paradigm is being widely explored by researchers and institutions as a possible path to increase the sustainability of our economic system. Reuse, repair and recycling are becoming crucial activities in many sectors. At the same time, companies are showing an increasing interest for this new economic model. However, the state of the art shows that a deep research on CE assessment and indicators is still lacking, in particular on the micro level. This work tries to fill this gap, first analyzing the current literature on CE assessment, then proposing a reference framework for the monitoring phase of a CE strategy. Finally, the main existing environmental assessment methodologies based on indexes are analyzed according to their suitability to evaluate the circularity of a system. A systematic approach for the choice of the adequate methodology is also provided, highlighting the main critical steps in the assessment of a CE strategy. Further research could be focused either on the extension of this approach to include other assessment methods, and on the validation of this proposal in a case study.

Abstract The use of wastewater sludge as a source for energy and resource recovery is a good alternative for its management considering the legislation requirements and the circular economy principles. Recognizing sludge as a resource, not as a waste, has made researchers consider the recovery of valuable components from sludge, such as carbon and nutrients. The energy that can be obtained from wastewater sludge may be a sustainable solution to fulfill present and future energy requirements. This review discusses about the types of sludge produced by wastewater treatment plants (WWTPs), the technologies that can be implemented in the water and sludge line to reduce the sludge amount, as well as the conventional treatment and disposal methods. Moreover, the technologies that can be used to recover resources and energy in the context of circular economy are also presented, with a focus on Technology Readiness Level (TRL) and a critical overview of positive and negative aspects in implementation. A detailed description of some urban biorefineries aimed at the recovery of cellulose and nutrients and the production of bioplastics is further reported. The study ends with a discussion on the need for an appropriate methodological approach when proposing “end-of-waste” criteria for wastewater sludge derived products.

The objectives of this study were to examine the possibility of reducing the fuel consumption and CO2 emissions of harvesters during cut-to-length operations by applying various technical settings to the machine through the machine's own software package. The adjustment of machine settings had an effect on the fuel consumption per unit product (l m3) and can reduce the fuel consumption and CO2 emissions in cut-to-length harvesting operations. The main factor significantly affecting both fuel consumption and productivity was stem size. The study involved three cut-to-length machines operating in thinning with comparable stand environment and silvicultural prescriptions. The novelty of this work is in exploring the fuel saving potential of simple adjustments of machine settings in cut-to-length harvesting machines. Such adjustments have an impact on fuel efficiency and may reduce fuel consumption and CO2 emissions in cut-to-length harvesting operations. This work may result in a reduction of energy consumption and environmental pollution, thereby contributing to cleaner production. This study bridges the gaps between research, development and implementation: it offers practical solutions that may affect manufacturers as well as practitioners and entrepreneurs in the field. The outcome of this study may result in innovative technology development with less impact on the environment.