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The number and importance of renewable energy communities (RECs) are increasing in all European countries due to the support of EU and national policies in order to foster the energy transition through participatory strategies for distributed energy systems. However, their development is rather slow in some countries, including Italy. The paper addressed the issue of the emergence of these socio-technical configurations in Italy, after the related law which entered into force in 2020 allowing the possibility of creating them. Our study focused on the alliances among different actors (professionals, institutions, NGOs, citizens) highlighting possible trends or models for the future that need to be confirmed in further research. The approach proposed to analyse this current process is the Actor-Network Theory, aiming at drawing the assemblages of human and non-human actants at a general level. Accordingly, we selected three case studies in order to show their different ways of organising, the relevance of trust in establishing each REC and the influence of local context on the composition and features of the actor-networks. [ABSTRACT FROM AUTHOR]

In 2020 the European Commission approved the GND (Green New Deal), a strategic plan aimed at the decarbonization of the EU by 2050. In this scenario, the diffusion of alternative renewable energy sources (RESs) play a key role, particularly electric energy production from wind and photovoltaic power plants. Regardless, the nonprogrammable nature of these power sources led recent studies to focus the interest on the power-to-gas solution (PtG), consisting of the electrolytic transformation of excesses of unused electric energy into hydrogen. The complexity of this technology requires the development of strategic optimization models aimed at finding the best locations for new PtG plants in specific territorial scenarios. This paper presents the development of a GIS-based optimization model that combines an operational research approach with territorial services based on geographic information system (GIS) data. The study is located in Sicily (Italy), considering the large renewable energy penetration in the larger Mediterranean island. The developed model allows us to find the best location for new PtG installations in the considered area by combining GIS automated processing with cost function resolution. The results of this work could be useful in the years to come in light of the rapid spread of hydrogen energy production in Italy. [Display omitted] [ABSTRACT FROM AUTHOR]

Super-hot rock geothermal is an emerging source of renewable and carbon-free energy. This paper is the first attempt to explore fluid and heat flow dynamics in the reservoir-wellbore coupled system, to assess the power generation performance of a super-hot (>450 °C) enhanced geothermal system (EGS). We developed a high-performance code and built a 3-D wellbore-reservoir coupled model based on data from a recently completed deep-drilling project at Larderello, Italy. The general pattern of the super-hot EGS is characterized by a significant temperature plummet (>60 °C), after which the production fluid evolves from steam to a two-phase mixture till the end of the operation period. Reservoir pressure emerges as a key parameter to determine the temperature of the two-phase mixture. By realistically capturing phase transitions driven by coupled thermo-hydraulic processes during operations, our numerical model predicts a lower power generation efficiency compared to previous attempts based on ultra-simplified models. Although finalized at assessing the thermodynamic viability of a specific system, this modeling approach provides general information on fundamental thermo-hydraulic processes in the Earth crust that might be applied for the design of similar EGS projects elsewhere. [ABSTRACT FROM AUTHOR]

The energy needs of a Net Zero Energy Building (NZEB) are fully met by renewable energy sources. Nevertheless, the time span of the energy balance can affect the effective energy self-sufficiency of the building. The aim of this paper is to demonstrate the lack of reliability that a yearly energy balance has in characterizing an NZEB. At this scope, comparisons between two different photovoltaic systems (fixed and tracking) and two kinds of energy balance (yearly and monthly) are made for a real NZEB building located in South-Italy. The investigation was carried out through dynamic energy simulations after validating the building model. The results show that the PV surface which attains the NZEB target on yearly basis not always achieves the same objective as the monthly balance. Furthermore, considering a monthly balance, the size of the photovoltaic system with biaxial solar tracking is 50% minor than the fixed one, thanks to a steadier energy production. Also, solar tracking systems show a significantly lower reduction of operational and embodied CO 2 emissions. A final technical-economic analysis shows, however, that design solutions that satisfy NZEB target not always can meet the financial interest of the private stakeholder, showing a high discounted payback period. • The energy needs of an existing NZEB are evaluated through dynamic simulation. • Fixed and tracking PV systems are designed and compared to obtain the NZEB target. • Comparisons between yearly and monthly balance using different PV systems are made. • Yearly balance is not adequate to characterize energy self-sufficiency for an NZEB. • Tracking PVs reduce monthly withdrawal from electricity grid and CO 2 emissions. [ABSTRACT FROM AUTHOR]

Non-dispatchable Renewable Energy Sources (RES) changed energy production from being centralised and fully dispatchable, to be more decentralised and less predictable. Despite the substantial growth, RES must be increased to fulfil the power production decarbonization targets set by several countries. In several countries, Italy included, RES development must be based on solar PV. Thus, relevant energy quantities will be shifted from day hours to night hours. Such "Load Shifting" is done with energy storage technologies. A few technologies suited for this task are already available, whereas several others have been proposed, but not tested in the practice. In this paper, such storage technologies are reviewed focusing on the performance and costs. Based on the review, current and future storage economic outlooks are assessed by focusing on the Italian scenario. In the paper, the storage operation is optimized at the hourly level to calculate the maximum achievable annual revenue. The optimisation is performed with a linear programming (LP) approach. Since none of the reviewed storage is economically feasible, the energy price modification required to achieve feasibility are estimated. Based on such results, the distance between the current situation and the one favourable to storage is assessed. In this way, the future outlook of each storage technology is discussed. • A review of storage technologies suited for grid-scale applications is presented. • The data from the review are used for an economic feasibility analysis. • The revenue is maximised over a year through a linear programming problem. • The cost over revenue ratio quantifies the required incentive from support schemes. • The energy price modification required to make any storage feasible is discussed. [ABSTRACT FROM AUTHOR]

This paper aims to broaden the concept of Net Zero Energy Building (NZEB), assessing its suitability to the emerging grid-based energy sharing models. The energy exchange between two buildings with shifted load schedules, namely, a new residential NZEB (prosumer) and an existing school building (consumer), is analysed to investigate energy sharing dynamics. The buildings are in Southern Italy, a region with high solar radiation. The model of the existing school building is calibrated on measured data and the study is performed by dynamic energy simulation. Three energy sharing scenarios based on the design of a photovoltaic system installed on the roof of the NZEB have been investigated, i.e., PV system peak power designed: to satisfy the NZEB target on annual basis; to satisfy the NZEB target on monthly basis; to fully exploit the available roof area of the NZEB. Considering annual and monthly net energy balances, oversizing the NZEB PV system leads to the compensation of a high share of school building non-renewable energy consumption. However, self-consumption analysis performed on hourly basis shows that increasing the PV system size negatively affects the self-consumption rate of the renewable energy community, and the presence of the school building only mitigates this effect. [ABSTRACT FROM AUTHOR]

Tobacco is traditionally used for cigarettes and cigars manufacturing and after the drying process a great quantity of dry tobacco stalks is treated as waste. In this framework, the scope of the paper is to examine the use of tobacco stems to feed a biomass boiler after a chipping process. The study is focused on southern Italy area thus, firstly, the assessment of tobacco availability in Italy and Campania region has been determined. Then, Burley tobacco stalks sampled out in an air-curing factory of south Italy crop have been characterized according to ASTM D5142 and ASTM D5373 standards. Thereby, biomass and natural gas fuelled boilers have been compared through an energy, environmental and economic analysis on simulative basis. Both systems satisfy the thermal energy demands of a multi-purpose condominium located in a cold Italian climatic zone near the factory. The results have demonstrated that boiler fed by tobacco chips ensures environmental and economic advantages compared to traditional system. In particular, it guarantees a reduction of CO 2 emissions up to 16.59 tCO 2 in one of investigated scenarios and a simple payback period and a net present value of about 5.6 years and 17,168 € (without economic support), respectively. • Tobacco stalks availability in Italy and Campania region is assessed. • Tobacco stems proximate and ultimate analyses show results similar to woody biomasses. • Boiler fed by tobacco chips and natural gas fuelled one are modelled and simulated. • A techno-economic and environmental performance comparison is implemented. • The energy, environmental and economic results reward plant fed tobacco by chips. [ABSTRACT FROM AUTHOR]

The present paper concerns the assessment of biomass by-products from the urban greenery maintenance with an energy perspective. Usually pruning is not organized by a consolidated planning practice, mainly because of lack of information. After estimating the quantity of wood pruning by-products by means of dendrometric equations and the availability of information on current greenery management, an innovative GIS-based method was implemented and tested on Milan, in northern Italy. The main outcome is the quantification of the energy potential in terms of available wood biomass, displayed on a geo-referred urban map. Moreover, the outcomes of the research could support the administrations in improving the management of these materials otherwise wasted and therefore in converting public expenses for maintenance into public profits available for further investments. On the energy supply side, the GIS database could support the local matching between available renewable sources and energy supply systems in operation (i.e. local district heating and cogenerative systems), providing a low-range and cost-effective renewable resource, also enhancing circular economy at the local scale. • A novel method for an effective urban greenery management is proposed and analysed. • Dendrometric equations and a GIS were combined for pruning by-products estimation. • The urban greenery of Milan was considered as case study. • A biomass PE potential between 26 and 76 GWh was assessed for the case study. • The use of pruning by-products in a biomass district heating plant is evaluated. [ABSTRACT FROM AUTHOR]

Decarbonization of the electricity sector is one of the major measures in slowing down the pace of climate change. In this paper, we analyze the impacts of energy storage systems (ESS) and year-to-year variability and uncertainty in the hourly profiles of variable renewable energy (VRE) on power system decarbonization in 2050. We perform this analysis through capacity expansion optimization based on technology cost projections and CO 2 emission restrictions based on 11 years of wind, solar, and load data variations in Italy's power system, with a particular focus on how ESS changes the optimal generation portfolio and system performance. We also explore the impact of ESS duration on the renewables' adoption and system costs. To quantify the impact of VRE variability in different years, we present a comparative analysis of capacity expansion optimization based on multiple-year and single-year data. Our results indicate a high RES penetration even in the absence of decarbonization policies, due to expected declines in future technology costs. In the transition to a zero-carbon electricity system, carbon capture and storage (CCS) with less than 100% carbon capture efficiency will play a role only in intermediate low-emission scenarios unless future technology advancements improve its capture efficiency. ESS investments contribute to lower total system costs by replacing more expensive flexibility resources. However, the value of ESS changes by its duration, with longer ESS durations having lower marginal value per added kWh storage capacity. Variability in VRE profiles leads to substantial variation in the system's configuration and energy cost, depending on what year is used in the optimization. Decision making based on single-year data can therefore lead to substantial increases in the systems' operational costs in other years due to increased probability of capacity shortages and load curtailments. In contrast, optimizing over multiple VRE and load years provides a more robust and cost-effective generation expansion strategy. • Results show high RES penetration levels even without decarbonization policies. • Decarbonization is less expensive with ESS, under given cost assumptions. • The marginal value of EES drops rapidly as more capacity is added. • Annual variations in VRE significantly change the system configuration and costs. • Planning with single-year data can lead to high operational costs in other years. [ABSTRACT FROM AUTHOR]

Although it is widely accepted that renewable energy consumption is vital for environmental sustainability, the environmental effectiveness of individual renewable energy types is often overlooked. Therefore, this paper examined the multivariate relationship between disaggregated renewable energy (hydroelectricity, wind, solar and biomass) consumption, economic growth and environmental pollution for the period from 1991 to 2014 in G-7 (The Group of Seven) countries. The study used both augmented mean group estimator and panel bootstrap causality method to consider the cross-sectional dependence and country specific heterogeneity across G-7 countries. Empirical findings indicate that increasing biomass energy consumption was efficient to reduce carbon emission in France, Germany, Japan and the United States; increasing hydroelectricity usage was efficient to reduce carbon emission in Italy and the United Kingdom; wind energy consumption reduced emission in Canada and solar energy usage was efficient on reducing emission in France and Italy for observed period. Moreover, in case of panel, it is found that increasing hydroelectricity, biomass and wind energy consumption reduced carbon emissions while the impact of solar energy consumption is statistically insignificant in G-7 countries. In addition, the hydroelectricity consumption was found the most efficient renewable energy source to reduce environmental pollution for the panel of G-7 countries. • Disaggregated renewable usage consumption and carbon emission nexus is investigated. • Increasing hydroelectricity usage reduces emission in Italy, the UK and the US. • Increasing wind energy usage reduces emission in all G-7 countries excluding Japan. • The effect of solar energy consumption on emissions is statistically insignificant. [ABSTRACT FROM AUTHOR]

Italy has reconsidered incentives on Renewable Energy Sources (RES) to implement the EU clean energy transition and Renewable Energy Communities (REC). Legislation on RECs shifted the focus of incentives from production to self-consumptions. In this paper, the REC model is studied in a minor island disconnected from the national grid, with strongly seasonal energy load and water demand. This is a typical Mediterranean scenario where energy demand is covered by Diesel gensets and water supply is provided with tankers. The implementation of RES is investigated, exploiting the current REC model of incentives. Two sub-optimal REC configurations were defined using time-dependent simulations on pyRES, an in-house code for energy systems. Results show the economical unfeasibility of REC when there is a poor mix of users. In contrast, REC can achieve economic profitability including industrial demand of a desalination unit (DES). The increase of self-consumption guaranteed from the DES allows to increase the NPV of the community and results in major cuts in CO 2 emissions (60% of those related to water supply and 10% of those from Diesel gensets) and a reduction of fuel costs of 22%. This method can be applied to investigate the performance of a REC in a local environment and help stakeholders in planning the expansions of RECs on the territory. [ABSTRACT FROM AUTHOR]

This paper explores the performance of public spending on the renewable energy sector. A panel Data Envelopment Analysis is employed to obtain efficiency scores. The case study is Italy and its 21 regions that implemented a Regional Energy Plan between 2003 and 2010. The findings show that special statute regions and Southern regions perform best in terms of technical efficiency under variable return to scale (VRS). On the whole, Italy shows an increase in the energy efficiency. Based on the Simar-Wilson bootstrap approach, a post-DEA is also run. These results provide evidence that being a southern region has a positive effect on the level of efficiency. Real GDP and the number of graduates in technical and scientific disciplines have a positive impact on the efficiency of the public intervention on renewable energy. [ABSTRACT FROM AUTHOR]