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The present work evaluates the environmental performance of three wave energy converters including on-shore oscillating water columns and oscillating floaters embedded in piers, and near-shore seabed-based buoys in the Mediterranean Basin. The life cycle assessment methodology was used to account for their potential environmental impact, in terms of carbon footprint (t CO2eq), considering four main phases, i.e., manufacturing of material components, assembling and installation on site, maintenance in time, and decommission end of life. Results show the greenhouse gas emission from different lifecycle processes, based on the inventory of main energy inputs and materials, highlighting the major impact of the manufacture of the structural components (52 %), especially due to the limited durability of materials. In order to compare the performances of the three different wave energy converters, the carbon intensity of electricity was evaluated considering a range of electricity production per technology based on data available in scientific literature. The results obtained for a single device (203–270 g CO2eq‧kWh−1 for the oscillating water column system; 94–374 g CO2eq‧kWh−1 for oscillating floater and 105–158 g CO2eq‧kWh−1 for the seabed-based buoy) highlight that wave energy converters are promising solutions to harvest wave energy, showing lower carbon intensity of electricity values compared to fossil energy sources; nevertheless, technological improvements are needed to increase efficiency and achieve the performances of other renewable energy sources. Moreover, the combination of wave energy converters with other solutions, such as offshore wind turbines, represents a valuable option in the future to increase productivity and foster energy transition of the Mediterranean regions.

Blue Energy (BE) is expected to play a strategic role in the energy transition of Europe, particularly toward the 2050 horizon. It refers to a set of Marine Energy Sources (MES), including offshore wind, waves, tides, marine currents, sea thermal energy, salinity gradients, and marine biomass, which are exploited by different BE technologies. Nevertheless, the implementation of integrated solutions to exploit MES in marine areas does not just concern technological issues; it requires inclusive planning practices considering different aspects regarding climate and environmental impacts, landscape compatibility, interference with other marine activities (such as shipping, fishing, and tourism), and social acceptance. A replicable BE planning framework has been developed based on interdisciplinary knowledge in three Mediterranean sites in Greece, Croatia, and Cyprus, under the scope of the Interreg Med BLUE DEAL project. It has been implemented by some interdisciplinary experts through a collaborative and iterative process of data elaboration, mapping, evaluation, and visualization. Results concern the localization of suitable sites to install BE plants and the estimation of potential energy production and avoided emissions in selected scenarios. Together with visual simulations, this study shows the potential effects of the implementation of BE in specific marine areas, with a special focus on the most promising offshore floating wind farms and wave energy converters (WECs), as basic information for participative design and stakeholder engagement initiatives, including public authorities, businesses, and citizens.

Floating wind turbines are a valid option for offshore wind farms in the Mediterranean, where the sea-floor falls off rapidly with distance from the coastline. The present study concerns a Life Cycle Assessment of the environmental performance of two types of floating wind turbine. Greenhouse gas emissions of two standard models (raft-buoy and spar-buoy, 154 m rotor diameter, 6 MW installed power) were estimated in terms of Global Warming Potential (t CO2eq) with the aim of determining a benchmark for evaluating the performance of similar offshore wind farms. Thus, the aim of the paper was to create a benchmark for the design of innovative technologies, such as those developed by specialist companies, and to verify the validity of new designs and technologies in terms of avoided greenhouse gas emissions. The results show that the Carbon Intensity of Electricity of a single floating wind turbine varies in the range 26–79 g CO2eq·kWh−1, averaging 49 g CO2eq·kWh−1, in line with other studies of offshore wind turbines and other renewable energy sources (such as onshore wind and photovoltaic). Extension of our study to the whole life cycle, including manufacturing, assembly and installation, maintenance and material replacement and a hypothetical decommissioning and end-of-life, showed that wind farms are among the most promising marine renewable energy technologies for the Mediterranean.

Coffee consumption is concentrated in the “Global North”, while production is mainly located in the “Global South”. This trade-driven dependency leads to the exploitation of natural resources. As an export-oriented cash crop, such dependency jeopardizes the existence of a fair distribution of the risks and revenues among all the actors taking part in its globalized supply chain. Coffee trees are mainly rain-fed and only partly irrigated. However, the increasing global coffee demand led to higher consumption of freshwater, which can exacerbate the stressed condition of already stressed water basins. This study quantifies the impact of global coffee consumption on water scarcity, considering the larger system made of producer and consumer countries. The global displacement of such impact is driven by consumer preferences. We found that the US, EU and Asian countries’ coffee consumption create impact on water scarcity mostly in African and South American countries, which is also representative of the economic disparities existing behind the global trade flows. Climate change will likely affect the varieties currently preferred by global consumers. Therefore, immediate environmental sustainability actions including water resource preservation are necessary to face current and future challenges.

The Danish diet is characterized by a high content of sugar, fat dairy products and red meat, and a low content of fruits and vegetables. As it is considered unhealthy and environmentally unfriendly, various alternatives to the standard Danish diet have been investigated and promoted in Denmark, such as the New Nordic Diet. By using a Life Cycle Assessment (LCA), this study estimates the carbon footprint (CF) of four different diet scenarios in Denmark: standard, carnivore, vegetarian and vegan. The LCA is applied to build a dataset of the 47 most widely eaten food and beverage products, which represent the average Danish eating habits and grouped into six food categories. Unlike most past LCA-based studies, where system boundaries are limited to the farm gate, this study covers all activities and relative use of materials and energy, from the food production phase to the final consumption (namely ‘from-cradle-to-fork’). We find that the highest CF value is associated with the carnivore diet, which has the highest impact (1.83 t CO 2eq person −1 year −1). The vegan and vegetarian diets record the best profiles (0.89 and 1.37 t CO 2eq person −1 year −1, respectively), whereas the standard Danish diet has a CF value of 1.59 t CO 2eq person −1 year −1. We find that the food production phase is the most significant in terms of CF (65–85%). This study confirms that dietary preferences are a strong driver of CF. A comparison with CF associated with other diets suggests that a further research could provide a guidance to promote healthy eating patterns with adequate nutritional values and better environmental performances.

The overexploitation of fossil fuels as main energy source to support the global economy is identified as the most responsible of the current critical situation from an environmental viewpoint. The need to replace fossil fuels has posed the attention on alternative energy sources such as biofuels, in both developed and developing countries. Africa, for example, has enormous natural resources in the form of biomass from agriculture and other related processes (i.e., food residues). An action that can help fight climate change is the implementation of biofuel refineries to maximize the value of biomass by converting it into a range of products, like energy vectors, biomaterials, feed and fertilizers. By using emergy evaluation and Life Cycle Assessment (LCA) this study focused on the potential development of sustainable biotechnological processes fed by biowaste and bioresidues in two African countries (Egypt and Ghana). We assessed the sustainability level of two biofuel productions based on starch and lignocellulosic feedstocks (i.e., cassava peel and corn stover, respectively). A first understanding of the sustainability of the case studies was obtained and the results showed that the biorefinery based on cassava peel was more sustainable from both the user and donor perspectives. Indeed, the LCA results showed that impact categories Global Warming Potential (GWP) and Acidification Potential (AP) had lower values for cassava compared to corn stover biorefinery and emergy outcomes highlighted that the starch-rich feedstock had lower Unit Emergy Value (UEV) and higher renewability percentage (94%). These results suggest that biorefineries are an option for world bioeconomy strategy as they enable optimization of agricultural and food residues and their environmental performance in producing a renewable substitute for fossil fuels and other non-renewable materials is promising.

The environment may constrain economic growth potential. In other words, economic growth cannot be pursued in spite of ecological limits any longer. Here we present an economic growth indicator adjusted by taking into account the current tendency of national economies to overcome the availability of natural resources and ecological dynamics. We combine two indicators: 1) the Output Gap, a measure of production capacity of the economy based on the difference between actual and potential GDP, as a per cent of potential GDP; 2) the difference between the Ecological Footprint and the Biocapacity of a country, systemic indicators representing the extent to which a country operates within or beyond ecological limits. That combination gives rise to the Biocapacity Adjusted Economic Growth indicator which enables a categorization of countries based on assessment of growth patterns in line or not with sustainability principles.

Due to growing interest in biofuels as alternative renewable energy sources, several recent studies have assessed the sustainability of their production. Emergy is a widely used environmental indicator for this purpose, as it counts exploitation of natural resources and direct and indirect solar energy requirements of biofuel production. Depending on whether a biofuel is first, second or third generation, its production system differs in nature and the indications derived from emergy evaluations vary as well. This article aims to provide guidelines on how to interpret and properly use the results of emergy evaluation of first, second and third generation biofuels. These guidelines are useful for correct emergy assessment of biofuels and clarify the actual meaning of emergy evaluation outcomes.

The comparison of the Ecological Footprint and its counterpart (i.e. biocapacity) allow for a classification of the world's countries as ecological creditors (Ecological Footprint lower than biocapacity) or debtors (Ecological Footprint higher than biocapacity). This classification is a national scale assessment on an annual time scale that provides a view of the ecological assets appropriated by the local population versus the natural ecological endowment of a country. We show that GDP per capita over a certain threshold is related with the worsening of the footprint balance in countries classified as ecological debtors. On the other hand, this correlation is lost when ecological creditor nations are considered. There is evidence that governments and investors from high GDP countries are playing a crucial role in impacting the environment at the global scale which is significantly affecting the geography of sustainability and preventing equal opportunities for development. In particular, international market dynamics and the concentration of economic power facilitate the transfer of biocapacity related to "land grabbing", i.e. large scale acquisition of agricultural land. This transfer mainly occurs from low to high GDP countries, regardless of the actual need of foreign biocapacity, as expressed by the national footprint balance. A first estimation of the amount of biocapacity involved in this phenomenon is provided in this paper in order to better understand its implications on global sustainability and national and international land use policy. Refereed/Peer-reviewed

An evaluation of the investment required to implement a second generation bioethanol production chain is presented in this study. An integrated agro-industrial system can be an appropriate solution to accomplish the European requirement for the partial substitution of bioethanol for gasoline by 2020. A biorefinery system is hypothesized within the Province of Siena (Italy), fed by residual energy and material flows from local productions: straw from agriculture and residual geothermal heat from geothermal electricity generation; the output is calibrated to replace 10% of gasoline consumption within the Provincial area. The physical consistency of the investment required to implement the production process, as well as the benefit of the biofuel–gasoline substitution, have been evaluated by means of the emergy methodology. Emergy is a thermodynamics-based indicator that contributes to identify and measure all the inputs supporting a given system, expressed in a common unit (solar emergy Joules – semj). Results show that the benefit of saving gasoline, in emergy terms, almost doubles the emergy investment to produce biofuel. The case of a biorefinery fed by natural gas instead of local residual geothermal heat is also presented. The Unit Emergy Investment (UEI) of bioethanol produced in a biorefinery that uses residual straw and geothermal heat is 9.16E + 08 semj/g (the case of the Province of Siena); it is 1.84E + 09 semj/g (in case natural gas is used to fuel the process). Finally, the comparison between the UEI of bioethanol evaluated in this study and UEV of bioethanol calculated in other studies is presented.

This study aims to assess the sustainability of an agroforestry system: i.e. a system obtained by the union of two productions to get at least two by-products from the same productive space. In particular, this case study presents the integration of a goose raising system with an organic grape production, from an environmental point of view. This integration is mainly designed to have two simultaneous co-products (grape and goose meat) with: i) a less intensive use of machineries for weeding and ii) avoiding use of chemical fertilizers and weeding. The sustainability is assessed by means of emergy evaluation. Emergy is a thermodynamic based tool able to estimates the environmental cost of products and services in terms of the solar energy (directly and indirectly) required for its production. As Emergy is not a state function, its final value depends on the way the product is made. The set theory applied to the emergy evaluation enables the comparison between the integrated system and the originating isolated systems in a proper way. Results confirm that the integrated system enables a saving, in emergy terms, amounting to 33% compared to the two originating isolated production systems. Emergy evaluation is able to keep track of the lower amount of resources required from outside the agroforestry system due to the optimization of resources internally available.

One of the main goals of any (sustainability) indicator should be the communication of a clear, unambiguous, and simplified message about the status of the analyzed system. The selected indicator is expected to declare explicitly how its numerical value depicts a situation, for example, positive or negative, sustainable or unsustainable, especially when a comparison among similar or competitive systems is performed. This aspect should be a primary and discriminating issue when the selection of a set of opportune indicators is operated. The Ecological Footprint (EF) has become one of the most popular and widely used sustainability indicators. It is a resource accounting method with an area based metric in which the units of measure are global hectares or hectares with world average bio-productivity. Its main goal is to underline the link between the (un)sustainability level of a product, a system, an activity or a population life style, with the land demand for providing goods, energy, and ecological services needed to sustain that product, system, activity, or population. Therefore, the traditional rationale behind the message of EF is: the larger EF value, the larger environmental impact in terms of resources use, the lower position in the sustainability rank. The aim of this paper was to investigate if this rationale is everywhere opportune and unambiguous, or if sometimes its use requires paying a special attention. Then, a three-dimensional modification of the classical EF framework for the sustainability evaluation of a product has been proposed following a previous work by Niccolucci and co-authors (2009). Finally, the potentialities of the model have been tested by using a case study from the agricultural context.