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Technologies to produce electric energy from renewable geothermal source are gaining increasing attention, due to their ability to provide a stable output suitable for baseload production. Performing life cycle assessment (LCA) of geothermal systems has become essential to evaluate their environmental performance. However, so far, no documented nor reliable information has been made available for developing robust LCA studies. This work provides a comprehensive inventory of the Italian Bagnore geothermal power plants system. The inventory is based exclusively on primary data, accounting for every life cycle stage of the system. Data quality was assessed by means of a pedigree matrix. The calculated LCA results showed, with an overall low level of uncertainty (2–3%), that the commissioning and operational phases accounted for more than 95% of the environmental profile. Direct emissions to atmosphere were shown to be the major environmental impact, particularly those released during the operational phase (84%). The environmental performances comparison with the average Italian electricity mix showed that the balance is always in favor of geothermal energy production, except in the climate change impact category. The overall outcome confirms the importance, for flash technology employing fluid with a high concentration of gas content, of using good quality primary data to obtain robust results.

Heat production from a geothermal energy source is gaining increasing attention due to its potential contribution to the decarbonization of the European energy sector. Obtaining representative results of the environmental performances of geothermal systems and comparing them with other renewables is of utmost importance in order to ensure an effective energy transition as targeted by Europe. This work presents the outputs of a Life Cycle Assessment (LCA) performed on the Rittershoffen geothermal heat plant applying guidelines that were developed within the H2020 GEOENVI project. The production of 1 kWhth from the Rittershoffen heat plant was compared to the heat produced from natural gas in Europe. Geothermal heat production performed better than the average heat production in climate change and resource use, fossil categories. The LCA identified the electricity consumption during the operation and maintenance phase as a hot spot for several impact categories. A prospective scenario analysis was therefore performed to assess the evolution of the environmental performances of the Rittershoffen heat plant associated with the future French electricity mixes. The increase of renewable energy shares in the future French electricity mix caused the impact on specific categories (e.g., land use and mineral and metals resource depletion) to grow over the years. However, an overall reduction of the environmental impacts of the Rittershoffen heat plant was observed.

Geothermal energy could play a crucial role in the European energy market and future scenarios focused on sustainable development. Thanks to its constant supply of concentrated energy, it can support the transition towards a low-carbon economy. In the energy sector, the decision-making process should always be supported by a holistic science-based approach to allow a comprehensive environmental assessment of the technological system, such as the life cycle assessment (LCA) methodology. In the geothermal sector, the decision-making is particularly difficult due to the large variability of reported results on environmental performance across studies. This calls for harmonized guidelines on how to conduct LCAs of geothermal systems to enhance transparency and results comparability, by ensuring consistent methodological choices and providing indications for harmonized results reporting. This work identifies the main critical aspects of performing an LCA of geothermal systems and provides solutions and technical guidance to harmonize its application. The proposed methodological approach is based on experts’ knowledge from both the geothermal and LCA sectors. The recommendations cover all the life cycle phases of geothermal energy production (i.e., construction, operation, maintenance and end of life) as well as a selection of LCA key elements thus providing a thorough base for concerted LCA guidelines for the geothermal sector. The application of such harmonized LCA framework can ensure comparability among LCA results from different geothermal systems and other renewable energy technologies.

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies.

This study evaluates the potential of biomass ash as raw clinker material and the influence of biomass feedstock and thermal conversion technology on biomass ash properties. Wood biomass has the highest potential to provide the right CaO/SiO2 ratio which is needed to form clinker minerals. Bark content and exogenous Si inclusion in wood biomass have a large influence on the CaO/SiO2 ratio. Paper sludge is composed of Ca, Si and Al and can potentially serve as a source of cement elements. Wood fly ash from pulverized fuel combustion can substitute a considerable amount of raw clinker materials due to its similar burnability. The replacement ratio is determined by the content of adverse elements in the ash (i.e. MgO and P2O5). The potential of fly ash from fluidized bed combustion to substitute raw materials was shown to be lower than that of wood ash from pulverized fuel due to the lower burnability. Using biomass ash to lower the CO2 emission from clinker production depends on the joint effort of bioenergy producers, by providing higher quality biomass ash, and cement makers, by adapting the kiln operation to enable a high level of raw material replacement by biomass ash. The presented evaluation of the ash production chain, from biomass selection through combustion technology and ash management, provides new insights and recommendations for both stakeholders to facilitate this sustainable development.

Purpose : This study evaluates the potential of biomass ash as raw clinker material and the influence of biomass feedstock and thermal conversion technology on biomass ash properties. Methods : A set of criteria for biomass feedstock and ash properties (i.e. CaO/SiO 2 ratio and burnability) are established. A large dataset was collected and the best combination of biomass feedstock and conversion technology regarding the desired ash quality was identified. Results : Wood biomass has the highest potential to provide the right CaO/SiO 2 ratio which is needed to form clinker minerals. Bark content and exogenous Si inclusion in wood biomass have a large influence on the CaO/SiO 2 ratio. Paper sludge is composed of Ca, Si and Al and can potentially serve as a source of cement elements. Wood fly ash from pulverized fuel combustion can substitute a considerable amount of raw clinker materials due to its similar burnability. The replacement ratio is determined by the content of adverse elements in the ash (i.e. MgO 2 and P 2 O 5 ). Conclusion : Using biomass ash to lower the CO 2 emission from clinker production depends on the joint effort of bioenergy producers, by providing higher quality biomass ash, and cement makers, by adapting the kiln operation to enable a high level of raw material replacement by biomass ash.The presented evaluation of the ash production chain, from biomass selection through combustion technology and ash management, provides new insights and recommendations for both stakeholders to facilitate this sustainable development. Graphic Abstract

Refractory metals are being studied as alternatives to Pd and its alloys for the separation of hydrogen in high-temperature processes. The development of a membrane reactor for the production of hydrogen via water splitting has required studying hydrogen permeability through Ta at temperatures above 1273 K, for which no data is available in the literature. A dedicated experimental setup has been realized for testing Ta tubes in the temperature range 673-1573 K. Despite the use of controlled atmospheres and ultra-pure gases (with oxygen content below a few ppm), the tests over 1473 K have involved the formation of oxide layers over the metal surfaces, as verified by SEM-EDS analyses. The presence of oxide layers significantly increases the energy barrier to permeation: in agreement with a modest surface oxidation, at lower temperatures (673-1273 K) the activation energy of 2679.8 K has been measured against the value of 30,691 K measured in the high-temperature tests (1473-1573 K).

The ASTRI Mini-Array is an international collaboration led by the Italian National Institute for Astrophysics (INAF) that will operate nine telescopes to perform Cherenkov and optical stellar intensity interferometry (SII) observations. At the focal plane of these telescopes, we are planning to install a stellar intensity interferometry instrument. Here we present the selected design, based on Silicon Photomultiplier (SiPM) detectors matching the telescope point spread function together with dedicated front-end electronics.

The BEST (Beerkan Estimation of Soil Transfer parameters) method was used to compare the hydraulic properties of the soils in two Long-term Agroecosystem Experiments (LTAEs) located at the FIELDLAB experimental site of the University of Perugia (central Italy). The LTAE “NewSmoca” consists of a biennial maize-durum wheat crop rotation under integrated low-input cropping systems with (i) inversion soil tillage (INT) or (ii) no-tillage (INT+) and (iii) under an organic cropping system with inversion soil tillage (ORG). ORG and INT+ involve the use of autumn-sown cover crops (before the maize cycle). Pure stand durum wheat was grown in INT and INT+, while a faba bean–wheat temporary intercropping was implemented in ORG. The LTAE “Crop Rotation” consists of different crop rotations and residue management, a continuous soft winter wheat and biennial rotations of soft winter wheat with maize or faba bean. Each rotation is combined with two modes of crop residue management: removal or burial. For INT+, despite the high-bulk density (>1.50 g/cm3), we found that conductivity, sorptivity and available water are comparable to those of INT, probably due to a more structured and efficient micropore system. ORG soils show the highest conductivity, sorptivity and available water content values, probably due to the recent spring tillage occurring in the wheat inter-row with the faba bean incorporation into the soil. For LTAE Rotation, the residue burial seems to influence the capacity-based indicators positively. However, the differences in the removal treatment are minor, and this could be due to the inversion soil tillage, which limits the progressive accumulation of organic matter.

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the feed additive consisting of endo‐1,4‐beta‐xylanase (produced with Trichoderma reesei MUCL 49755), endo‐1,3(4)‐beta‐glucanase (produced with T. reesei MUCL 49754) and polygalacturonase (produced with Aspergillus fijiensis CBS 589.94) (AveMix® 02 CS/ AveMix® 02 CS L) as a zootechnical feed additive for weaned and suckling piglets. The additive is already authorised for use with weaned piglets. This scientific opinion concerns the request for the renewal of the authorisation of the additive for weaned piglets and the extension of use to suckling piglets. The applicant provided evidence that the additive currently in the market complies with the conditions of the authorisation. There was no new evidence that would lead the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) to reconsider its previous conclusions that the additive is safe for weaned piglets, the consumer and the environment under the authorised conditions of use. This conclusion applied also to the new target species (suckling piglets) for which a request for an extension of use was made. The additive in both formulations (powder and liquid) is not irritant to skin or eyes but should be considered a dermal and respiratory sensitiser. There was no need for assessing the efficacy of the additive in the context of the renewal of the authorisation for weaned piglets. The Panel concluded that the additive is efficacious in suckling piglets at 2140 XU, 1230 BGU and 46 PGLU/kg complete feed.