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Due to huge energy potential of sea waves, many technologies have been proposed in the last few years. Some concepts have been developed and sometimes also tested in the open sea. Some prototypes use linear generators to directly convert the vertical motion of buoys into electrical energy. This solution minimizes the numbers of energy conversion steps, increasing the energy efficiency. At the same time, the limited numbers of components could also increase the reliability of the wave energy converter. For this reason, the development of linear generators is considered with great interest. This paper investigated the cogging force, a magnetic force due to the interaction between the magnets and the iron stator. To limit the cogging force, a modified shape of the stator is investigated. Simulations on a specific FEM software are performed, obtaining interesting results.

This work shows an example of energy saving interventions on the ventilation system of a big shopping center. This kind of buildings is characterized by high energy consumptions, because of the high level of yearly operating hours and the use of obsolete technologies. In the case study, a big Do It Yourself (DIY) shop located in the southern part of Italy is analyzed, proposing two different approaches aimed at reducing the annual energy consumption for the indoor air exchange of the sales area. In the AS-IS scenario, a centralized HVAC plant, composed by six rooftops, is installed on the roof of sales area, working with fixed airflow value. The first retrofit solution involves the installation of heat recovery exchanger, reducing the energy demand for the air thermal treatment without changing the airflow. In the second scenario, a smarter solution is proposed, considering the installation of air quality sensors able to modulate the air exchange rate according to the real requirement for the indoor health. Finally, the application of both retrofit solution is considered. For each scenario, the paper reports the evaluation of the yearly energy saving and the avoided CO2 emissions as environmental benefits. As regard the economic evaluation, the annual avoided expenditure, the breakeven time of the investments and the discounted cash flow are provided.

Nowadays the electrical energy production is based on fossil fuels in the greatest part of smaller islands in the Mediterranean Sea. Despite the availability, the renewable energy sources are practically unused, as landscape constraints. So, the paper presents the case of study of Ustica, a small island located at north of Sicily, in the middle of Mediterranean Sea. Starting with the analysis of the electrical energy consumption of public buildings, the paper suggests an energetic scenario, based on solar and sea wave. In particular, in order to use this new resource, the paper presents an innovative wave energy converter. Finally, the energetic and economic evaluations encourage the realization of the project.

Renewable energy sources are expanding around the world, with significative results in the electricity generation sector. Despite this, the share of renewable energy sources in small islands is very low, except in rare cases. In this context, the paper analyses the energy mix currently used to produce electricity in the Balearic Islands and the Fiji Islands. These two archipelagos show several differences but have in common the strong energy dependence from fossil fuels. In order to increase the energy sustainability of small islands, a preliminary energy assessment is realized, using climate data collected from GIS-tools and introducing a numerical approach. As target, the Authors considers satisfying the major part of the prevision of electrical energy demand by 2025, compatibly with the electrical request and proposing a renewable energy mix based on wind, solar and sea wave. The last source represents a new entry in the renewable energy sector, so for its use an innovative technology is presented. The device is at the design step by the Department of Energy of the Palermo University. Thanks to the cooperation with the University of South Pacific, the paper suggests the installation of a sustainable renewable energy mix to supply the Balearic Islands and Fiji Islands, evaluating the potential environmental benefits.

The paper analyses the theme of water energy nexus, investigating a specific industrial process: desalination. In particular, the paper reports a case of study, applied in the small island of Lampedusa, located at south of Sicily (Italy). As the many small islands in the middle of the Mediterranean Sea, Lampedusa presents a small electrical grid, not connected to the mainland. The electrical production is entrusted to old diesel engines, consuming fossil fuel, transported by boat from Sicily. Besides, the renewable energy sources are extremely underdeveloped in this territory, since the environmental constraints make complex the use of technologies, like wind turbines or photovoltaic panels. Furthermore, Lampedusa is regularly affected by water scarcity, so freshwater is produced by desalination plants and sometimes transported by boat. In this context, the paper analyses the energy demand for the desalination process and evaluates an interesting renewable energy source, available in the small island: sea wave. Proposing an innovative technology for the exploitation of this resource, the paper estimates the electrical energy production considering the realization of a sea wave energy farm, able to cover the electrical energy demand of the desalination plants, located in Lampedusa.

This paper analyses technical and economic aspects relative to a hypothetical wind farm installed inside the park of Madonie (Sicily) that produces electric energy for the direct use and to supply an electrolytic system for the production of hydrogen. User is formed by approximately 20,000 persons who live in the mountain localities of the park. Global energy required by user was estimated carrying out hypotheses on daily power demand. Discontinuous power makes inescapable to connect wind farm to grid, so that energy demand of user is partially satisfied by means of energy wind, while the remaining part becomes from grid. Surplus of power that turbines make available when wind speed is particularly high is used to supply electrolytic system. Technical and economic analyses were developed by using the results of simulations carried out by software “HOMER” realized by National Renewable Energy Laboratory and Midwest Research Institute of United States. Simulations allowed determining approximately the size of devices and to estimate the cost due to construction and maintenance of this hypothetical plant. The study also investigated the opportunity to amortize part of overheads by the sale of “green certificates” emitted, for the production of renewable energy, by GRTN, the Italian company for electric energy distribution, and to use hydrogen from electrolytic system to supply a hypothetical fleet of vehicles equipped by a hydrogen internal combustion engine.

The diffusion of technologies supplied by Renewable Energy Sources is contributing in the challenge of reduction of energy dependence from fossil fuels, avoiding the emission of several polluting substances and greenhouse gases. Despite the technological development and important results around the world, in several remote areas or small islands the electrical energy production is based on obsolete technologies, supplied by fossil fuels. This solution is not sustainable for the environment, as the emissions of several pollutants. Focusing the attention on small islands, these areas usually have a standalone grid, as the high cost to build an electrical connection to the mainland, in comparison with the electrical demand. The paper analyses the Aeolian Islands, located in the Tyrrhenian Sea, at north of Sicily, considering the current energy demand and evaluate the availability of renewable energy sources in the Aeolian Islands. With the goal of satisfying the electrical energy consumption in a sustainable way, the paper proposes an energetic mix based on renewable energy sources. The mix includes also sea wave, a new entry in the renewable energy context.