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Low-carbon/carbon-free fuels are shaping how will be the future of energy utilization in hard-to-abate sectors such as transport, heavy industries, power generation, building sector, and seasonal energy storage. This is projected to contribute to a 10% CO2 emission reduction by 2050. Storage and transportation are key elements in a hydrogen economy value chain which, will connect production facilities to end users. Transporting hydrogen in liquid form, via trucks and ships, has more techno-economic challenges than transport through pipelines. Therefore, the transportation and distribution of hydrogen purely through new pipelines and/or blending hydrogen with natural gas by repurposing existing Natural Gas (NG) pipelines are seen as more promising. Refurbishing pipelines is estimated to be about 33% of the cost of new infrastructure. Existing NG Transmission System Operators (TSOs) and Distribution System Operators (DSOs) are evaluating the technical readiness of their infrastructures. In this paper, the preliminary studies focus on the feasibility of extending the usage of current pipelines for the distribution of H2-NG blends. The study evaluates the H2-readiness of pipelines in a distribution network in Sicily for its technical adaptability, regulations, and legislation in this local zone. The study provides a review of the different steel types, microstructures, cathodic over-protection, and their impact on Hydrogen Embrittlement (HE). The effect of the interaction of HE gaseous inhibitors such as O2, CO, and SO2 is presented together with the counter-reactive effect of water vapor in the presence of SO2. Based on the case history, the barriers and enablers are critically evaluated for different H2-NG blends until a 10% maximum value which is a threshold in many EU countries. [ABSTRACT FROM AUTHOR]

Systems based on the coupling of heat pumps (HP) with solar hybrid photovoltaic and thermal technology (PVT) for domestic hot water (DHW) production are a valid alternative to conventional electric production systems. In previous research, simulation models were developed in order to study the dynamic behaviour of a plant set-up based on the integration of an air-to-water heat pump aimed at DHW production with a rated power of 700 W and a storage tank of 500 lt. It was coupled with a plant of 6 PVT flat uncovered hybrid solar collectors with a peak power of 300 W for each module. Starting from the results obtained in the pre-sizing stage, in this study, a plant configuration was analysed to maximize the exploitation of the low-temperature contribution provided by the adopted PVT collectors. With this aim, the efficacy of the introduction of a solar water preheating storage in addition to the one normally integrated into the HP was investigated. Different operational scenarios have been studied to evaluate the best energy management strategies to be implemented. They consider the influence that the thermal capacity of the solar storage could have on the system performance according to its volume and the setpoint temperatures. The obtained results show that the proposed plant solution generally allows an increase in solar energy exploitation for DHW production and a reduction in HP electricity consumption.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2010.02.028 Byline: Marco Beccali (a), Maurizio Cellura (a), Maria Iudicello (a), Marina Mistretta (b) Abstract: Though many studies concern the agro-food sector in the EU and Italy, and its environmental impacts, literature is quite lacking in works regarding LCA application on citrus products. This paper represents one of the first studies on the environmental impacts of citrus products in order to suggest feasible strategies and actions to improve their environmental performance. In particular, it is part of a research aimed to estimate environmental burdens associated with the production of the following citrus-based products: essential oil, natural juice and concentrated juice from oranges and lemons. The life cycle assessment of these products, published in a previous paper, had highlighted significant environmental issues in terms of energy consumption, associated CO.sub.2 emissions, and water consumption. Starting from such results the authors carry out an improvement analysis of the assessed production system, whereby sustainable scenarios for saving water and energy are proposed to reduce environmental burdens of the examined production system. In addition, a sensitivity analysis to estimate the effects of the chosen methods will be performed, giving data on the outcome of the study. Uncertainty related to allocation methods, secondary data sources, and initial assumptions on cultivation, transport modes, and waste management is analysed. The results of the performed analyses allow stating that every assessed eco-profile is differently influenced by the uncertainty study. Different assumptions on initial data and methods showed very sensible variations in the energy and environmental performances of the final products. Besides, the results show energy and environmental benefits that clearly state the improvement of the products eco-profile, by reusing purified water use for irrigation, using the railway mode for the delivery of final products, when possible, and adopting efficient technologies, as the mechanical vapour recompression, in the pasteurisation and concentration of juice. Author Affiliation: (a) Dipartimento di Ricerche Energetiche e Ambientali (D.R.E.AM.), Universita di Palermo, Viale delle Scienze, 90128 Palermo, Italy (b) Dipartimento di Arte, Scienza e Tecnica del Costruire (D.A.S.TE.C.), Universita Mediterranea di Reggio Calabria, Salita Melissari, 89124 Reggio Calabria, Italy Article History: Received 16 June 2009; Revised 7 January 2010; Accepted 7 February 2010