• Energy Research

Abstract The generation of RES electricity in urban areas is regarded as a key element in achieving the 20% emission reduction target by 2020, in line with the strategy adopted by the European Union (EU). To understand the actual role of renewable energy planning in cities, as well as the adequacy of the strategies adopted, the authors considered statistics officially reported by the Joint Research Centre of the EU which regard the totality of submitted SEAPs and ten Sustainable Energy Action Plans (SEAPs) as sample cities. The double survey has a dual goal: one, the collection of overall statistics to have a general framework of all cities that submitted their SEAPs and to verify their inclusion of renewables, and two, the analysis of urban planning processes and climatic features through a sample of representative cities to try to determine direct connections between the implementation of renewables and real source potentials (an aspect not present in the JRC reports). Making comparisons between SEAPs submitted by European cities, the authors report in the final discussion the merits and drawbacks of the planning and usage of renewable sources in urban areas, thereby highlighting some relevant critical points and possible directions for future research efforts.

For the agricultural sector to develop sustainably in the future, progress toward more environmentally friendly technologies and methods is crucial. It is necessary to increase output while reducing the demand for energy, agrochemicals, and water resources. Although greenhouses can be utilized successfully for this purpose, significant technical advancements are required, especially when it comes to heating, to lower the use of fossil fuels and boost energy efficiency. Microwaves can warm plants without heating the entire greenhouse volume, which takes a significant amount of energy to compensate for heat loss in the outdoor environment. In this paper, through a thorough examination of the state of the art, a general overview of novel greenhouse heating systems based on radiation is reported. First, the strengths and weaknesses of microwave heating are discussed, and finally, the use of microwaves for soil sterilization is examined. All outcomes suggest these irradiation-based technologies can contribute significantly to energetically sustainable agriculture; moreover, they can be used to increase plant comfort.

International cooperation is a must to achieve the goal of sustainable development, since only through cross border actions’ complex issues like environmental degradation can be faced. Supranational initiatives and shared objectives are the only path for getting a durable and effective green strategy, which transcends boundaries or governments and fosters a common effort for sustainability through networking. The European Neighborhood and Partnership Instrument (ENPI) aims at reinforcing cooperation between the European Union (EU) and partner countries’ regions placed along the shores of the Mediterranean Sea. To this extent, MESP (Managing the Environmental Sustainability of Ports for a durable development) can be considered as a typical cross border cooperation project, willing to create a sustainable environmental management of port in northern and southern shores of the Mediterranean basin. This has been achieved through the development of specific guidelines towards environmental sustainability and the collection of common tools, methodologies, good practices and innovations focused on pollution reduction that can be replicated in Mediterranean ports and further. This was possible through the creation of a strong cooperation network and long-lasting collaborations among partners and stakeholders such as harbour cities, port authorities, universities, research centres and scientific skills.

Abstract The pressure drop between the gas transportation grid and local networks can be exploited to generate electricity by means of a turbo expander. However, a lack of performance indicators leads to incomprehension and underestimation of the actual benefits in terms of energy savings and carbon emission reductions, thus limiting the diffusion of such smart, energy-saving technology. For this reason, in this study, key performance indicators are proposed for natural gas pressure regulation stations with energy recovery. The waste energy recovery index is introduced by considering the possibility of system thermal integration and a reference theoretical sideways process, where a Joule-Thompson expansion occurs. Furthermore, the reduction of greenhouse gas emissions is evaluated through the carbon emission recovery index that quantifies the environmental benefits of the energy saving action. Different key performance indicator values have been calculated by means of custom prediction models based on system characteristics. Finally, in order to assess the accuracy of such models, a parallel simulation is conducted using UniSim® Design Suite software. Here, the two system configurations are implemented: one related to the case study and one related to the reference sideways process. The results show that the model successfully predicts the heat needs of pressure reduction stations and, for a typical system configuration, characterised by an expansion ratio of 4.8, a maximum waste energy recovery of about 69% could be achieved when the system is operating at nominal conditions. Proposed KPIs turned out to be a helpful tool to manage design development and system operations. Moreover, the simplicity of the performance indexes makes them easy to implement in software for process control and simple to interpret for system operators.

To ensure European Union (EU) commitments to the Kyoto protocol, on 29 January 2008 the European Commission launched the Covenant of Mayors (CoM). This is an initiative aimed at unilateral and voluntary participation of European cities in energy efficiency improvement, renewable energy source usage increase, and greenhouse gas emission reduction by 2020. The Municipality of Genoa, Italy, joined the initiative on February 2009 and its Sustainable Energy Action Plan (SEAP), aimed at a 23.7% CO2 reduction by 2020, has been the first among European cities to be officially published by the European Commission. Following a description of EU environmental policies concerning the energy sector and related regulatory framework, this paper presents issues of CoM and SEAP from an overall standpoint and their application in the city of Genoa. The SEAP approach and criteria, initially considered at a general level, are then analyzed in detail with their operational consequences regarding the city. The Baseline Emission Inventory for the city, preparation of the SEAP, its implementation in the various sectors involved (buildings, renewable energy sources, transport, public policy, and others) are analyzed. Eventually, the SEAP monitoring strategy is addressed, considering assessment of the implemented actions, biennial monitoring report, and dynamic management of the CoM. In this way, a useful benchmark is provided to those facing this issue and, more generally, to those dealing with the management of energy sustainability at various levels.

Abstract World’s energy picture is still framed in a context characterised by extensive use of the natural gas. Luckily there are significant opportunities for increasing energy efficiency and fostering energy recovery in natural gas infrastructures. In particular integration with renewable energies is an asset to be exploited. This paper presents a novel configuration of the so-called natural gas pressure reduction stations equipped with sun-tracking parabolic trough solar collectors. In addition, the system is coupled with thermal energy storage. The energy and environmental performance of this new configuration is investigated with the support of a dynamic model implemented in Matlab-Simulink®. Energy saving has been calculated for three European cities, namely Genoa, Naples, and Amsterdam, characterised by different latitudes and hence solar irradiations. The results revealed that, despite the technical and physical constraints, it is possible to achieve carbon-free operations in summer periods for southern locations. The proposed system configuration has shown to be a strategic retrofit intervention to pursue reducing carbon emissions linked to the gas distribution operations.

AbstractIn this paper a numerical model aimed at studying dynamic behavior of CHP (Combined Heat and Power) plants is presented, paying particular attention to the components in which heat transfers take place. The analysis refers to a system powered by an internal combustion engine for a compression ignition type in cogeneration configuration, equipped with two heat extractors: the first one for coolant / water, the second one for exhaust gas / water. The numerical model has been implemented by using Matlab-Simulink software. After a description of the simplifying assumptions adopted for implementing the simulator, the model is exposed in detail with regards to each single element. Then simulation results are reported for two different operating conditions aiming to assess the effectiveness of the model in analyzing the dynamic behavior of CHP plants.

Within the framework of the European Combined Efficient Large Scale Integrated Urban Systems (CELSIUS) project, the Genoa demonstrator involves the insertion of a turbo expander (TE) to substitute the standard throttling process in a natural gas expansion station. In this way, the currently wasted mechanical energy will be recovered, while an internal combustion combined heat and power (CHP) unit will be used to meet the heating requirements of the gas before the expansion and to serve a small district heating network (DHN). Both TE and CHP are capable of delivering electric power (EP) up to 1 MW. In order to match the EP production vs demand is highly desirable to use the EP extra capacity for local EP final users, such as a nearby public school and a gas refueling station (RS). For limiting the school’s consumption of fossil fuel, it is possible to use the EP surplus generated by the demonstrator to feed a heat pump in parallel to the heating conventional system. With regard to the RS, the compressors are currently driven by electric motors, with a high-energy consumption. The integrated system gives the possibility of exploiting the surplus of electricity production and of recovering heat, which would be otherwise wasted, from the intercooling of compressed gas, thus powering the DHN through a preheating system. The result expected from this strategy is a relevant energy and emissions saving due to an integrated use of the electricity generated by the Genoese demonstrator for feeding the nearby school and RS.