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Electric vehicles are progressively emerging in the light-duty passenger market as a promising alternative to oil-dependent road transport in the attempt to reduce greenhouse gas and pollutant emissions. However, it is necessary to investigate how a significant penetration of electric vehicles in the private transport fleet would affect the strategic planning of large scale energy systems.This study evaluates the integration of electric vehicles in the Italian energy scenario and their synergy with electricity generation from renewable energy sources, identifying the impact in terms of CO 2 emissions, costs and curtailments on a medium-long term perspective. The national energy system has been accurately characterized using currently available data and its operation simulated with the EnergyPLAN software through an integrated analysis method. Possible energy scenarios have been defined with increasing shares of electric vehicles and intermittent renewable energy sources.Results assess the impact of electric vehicles in cutting private transport carbon emissions and the positive interaction with increasing levels of renewables under different vehicle charging strategies and the capability of electric vehicles to behave as an electricity storage system.

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Integration of renewable energy in the electricity market poses significant challenges on power grid management due to the volatility of these sources. In fact, the mismatch between renewable power generation and load curves, along with the need for grid stability, may lead to substantial curtailments when potential electricity supply exceeds demand. In this respect, the surplus from renewable energies can be conveniently exploited to produce hydrogen via electrolysis. This concept can be referred to as "Power-to-Gas" and "Power-to-Liquid" when synthetic grid gas and liquid fuels are respectively produced via syngas hydrogenation processes and is rapidly emerging as a promising measure in support of renewable energy penetration, leading to the decarbonisation of energy generation without affecting grid reliability. This study evaluates the impact of Power-to-Gas and Power-to-Liquid systems on future CO2-reduced scenarios, characterized by increasing shares of renewable energies and electric vehicles under a holistic Smart Energy System perspective. Results show potential synergies among crucial energy sectors in terms of CO2 emissions, curtailments and costs. Among the proposed options, synthetic grid gas produced by biomass gasification, and subsequent hydrogenation, leads to the best techno-economic scenario with a reduction of CO2 emission of 30% with negligible change in yearly total costs.

In 2004, the European Parliament and the Council of the European Union adopted the Directive 2004/8 EC whose purpose is to increase energy efficiency and develop high efficiency cogeneration of heat and power. Italy brought into force this law by means of the Legislative Decree February 8, 2007, n. 20: from January 1, 2011, the high efficiency cogeneration is the cogeneration that meets the requirements of Directive 2004/8/EC. Then, Italy adopted two ministerial decrees: the ministerial decree of Environment Ministry (August 4, 2011), that integrates the Decree n.20, and the ministerial decree of Ministry of Economic Development (September 5, 2011), that lays down the conditions and procedures for access to the support system of cogeneration: for each year in which the requirements of high efficiency cogeneration are met, the cogeneration units are entitled to energy efficiency certificates (White Certificates), whose number is proportional to the energy saving achieved.\ud \ud Therefore, from January 1, 2011 the legislative and incentive cogeneration context is radically changed and, consequently, new boundary conditions must be taken into account for feasibility studies and performance assessments of cogeneration plants. So, in this paper we want to evaluate the impact of this new legislative context on the competitiveness of the various cogeneration technologies. To this end, after an illustration of the new criteria to meet the qualifications of the high efficiency cogeneration, a comparison between different generation technologies will be developed by highlighting the impact of the new incentive context

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In January 2011, the introduction of high-efficiency cogeneration in Europe radically modified the incentive scheme for combined heat and power (CHP) plants. Since then, the techno-economic feasibility of new cogeneration plants in different areas of application (industry, service, residential, etc.), along with the definition of their optimal operation, have inevitably undergone a radical change. In particular, with reference to the Italian case and according to the most recent ministerial guidelines following the new EU regulation, in the event that cogeneration power plants do not reach an established value in terms of overall efficiency, their operation has to be split into a CHP and a non-CHP portion with incentives proportional to the energy quantities pertaining to the CHP portion only. In the framework of high-efficiency cogeneration, the present study compares different CHP solutions to be coupled with the paper industry that, among all the industrial processes, appears to be the best suited for cogeneration applications. With reference to this particular industrial reality, energy, environmental, and economic performance parameters have been defined, analysed, and compared with the help of GateCycle software. Among the proposed CHP alternatives, results show that gas turbines are the most appropriate technology for paper industry processes.

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