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This paper presents a new method, based on the Smart Energy Systems concept. The aim is to increase the share of renewable energy penetration on islands. The method is applied to the island of Gran Canaria (Spain), considering the entire energy system of the island. Several smart renewable energy strategies are proposed following a cross-sectoral approach between the electricity, heating/cooling, desalination, transport and gas sectors. The different smart renewable energy strategies were applied in a series of steps, while looking for a transition from the current energy system to a nearly 100% renewable energy system. Based on the results, the study concludes that the suggested method is applicable for increasing renewable integration on islands and can potentially be used in helping energy planners to take decisions about priorities in development of the sector to improve such integration. The results indicate that, for the case of Gran Canaria, a 75.9% renewable energy system could be attained with technologies that can be implemented at present. Furthermore, it is shown that a nearly 100% renewable energy system in Gran Canaria is technically feasible and could be achieved if certain technologies acquire greater maturity. © 2018 Elsevier Ltd 443 421 2,048 5,537 Q1 Q1 SCIE

The increasing depletion of natural resources, combined with a wider set of pressures on the environment, has, in recent years, highlighted the need for a more efficient use of energy and a development process that involves alternative energy sources. Energy efficiency has received much attention as a solution, implying both monetary and emissions savings. However, the latter may be partially offset by the income and demand effects of the former, both in more efficient sectors and in spreading to the wider economy. This is the problem of rebound effects. Taking Spain as a case study, and introducing an energy-related CGE model that develops the inclusion of renewables, this paper evaluates a combination of efficiency initiatives to deliver both reduced energy use by households and a more sustainable supply of energy. Our findings suggest that a package aimed at improving efficiency in household electricity and petroleum use, combined with a more competitive supply of energy from renewable sources, may be the only way to get reductions in all energy use, and thus benefit the economy. Specifically, we consider how this package may lead to positive economic impacts and associated rebound effects, where the latter are focused on a greener energy supply.

Abstract Building-integrated photovoltaics (BIPV) is a growing reality worldwide and its development involves implementing techniques to log and estimate the solar resources available. In this paper an easy methodology for the pre-classification of facades in BIPV projects has been described. This step is previous to the calculation of the complete solar potential in a building, and don't include the shape and shading factors. The proposed methodology covers the development of a new model that allows the irradiation factor (IF) to be estimated on facades with only 2 input parameters: the latitude of the place and the azimuth angle of the photovoltaic generator. The necessary tools to assess the “Energetic Efficiency Rating” for BIPV facades are provided, as an initial stage to be applied by architects and engineers.

This paper proposes a hybrid renewable energy system (HRES) consisting of photovoltaic (PV), wind and forest wood biomass power for cogeneration, and applies a multi-objective optimization methodology to study the trade-offs between life-cycle cost and environmental impact (EI) of such a system. The optimization is achieved by applying an operation strategy that maximizes the efficiency of the biomass power subsystem coupled with an optimization model based on the use of genetic algorithm (GA) to obtain the optimal system sizing. The system is designed to supply the electricity demand of a rural township and the thermal demand – both heating and sanitary hot water (SHW) – of a neighborhood in a district heating (DH) scheme. Indigenously available renewable energy sources (RES) are used, taking special care in the case of biomass to not exceed the self-growth rate of local tree species. Results show that by taking advantage of the thermal energy produced, the payback time of the investment required to install the system is significantly reduced, being profitable after 9 years. Furthermore, it is also observed that layouts with low costs have greater EI and vice versa. However, it is shown that moderate cost increases have great returns on EI reduction.

Abstract The implementation of externalities in energy policies is a potential measure for sustainability-oriented energy planning. Furthermore, decisions on energy policies and plans should be based on the analysis of a number of potential energy scenarios, considering the evolution of key techno-economic and life-cycle sustainability indicators. The joint interpretation of these multiple criteria should drive the choice of appropriate decisions for energy planning. Within this context, this work proposes –for the first time– the combined use of Life Cycle Assessment, externalities calculation, Energy Systems Modelling and dynamic Data Envelopment Analysis to prioritise prospective energy scenarios. For demonstration and illustrative purposes, the application of this methodological framework to the case study of electricity production in Spain leads to quantitatively discriminate between 15 prospective energy scenarios by taking into account the life-cycle profile of the transformation path of the power generation system with time horizon 2050. When compared to the application of the framework without implementation of external costs, the internalisation of climate change externalities is found to affect the ranking of energy scenarios but still showing the rejection of those scenarios based on the lifetime extension of coal power plants, as well as the preference for those scenarios leading to a high penetration of renewable technologies.

Abstract One of the prospective technologies that can be used for energy generation in distributed systems is based on biogas production, usually involving fermentation of various types of biomass and waste. This article aims to bring novelty on the analysis of this type of systems, joining together thermodynamic, economic and environmental aspects for a cross-cutting evaluation of the proposed solutions. The analysis is made for Spain, for which such a solution is very promising due to availability of the feedstock. A detailed simulation model of the proposed system in two different cases was built in Aspen Plus software and Visual Basic for Applications. Case 1 involves production of biogas in manure fermentation process, its upgrading (cleaning and removal of CO2 from the gas) and injection to the grid. Case 2 assumes combustion of the biogas in gas engine to produce electricity and heat that can be used locally and/or sold to the grid. Thermodynamic assessment of these two cases was made to determine the most important parameters and evaluation indices. The results served as input values for the economic analysis and environmental evaluation through Life Cycle Assessment of the energy systems. The results show that the analysed technologies have potential to produce high-value products based on low-quality biomass. Economic evaluation determined the break-even price of biomethane (Case 1) and electricity (Case 2), which for the nominal assumptions reach the values of 16.77 €/GJ and 28.92 €/GJ, respectively. In terms of environmental assessment the system with the use of biogas in gas engine presents around three times better environmental profile than Case 1 in the two categories evaluated, i.e., carbon and energy footprint.

Combined heat, cooling and power (CHCP) systems are interesting for the supply of different energy services in urban districts and in large buildings. CHCP systems utilize a fuel's energy to a greater extent, because the cogenerated heat can be used for heating in winter as well as for cooling in summer with an absorption refrigerator. The use of thermal energy storage (TES) provides the additional advantage of covering variable thermal demands while the production system operates continuously at nominal conditions. Thus, energy supply systems integrating the technologies of cogeneration, absorption refrigeration and thermal storage can provide substantial benefits from economic, energetic and environmental viewpoints. In this paper an optimization model is developed, using mixed integer linear programming (MILP), to determine the preliminary design of CHCP systems with thermal storage. The objective function to be minimized is the total annual cost. Taking into account the legal constraints imposed on cogeneration systems in Spain, the optimization model is applied to design a system providing energy services for a set of buildings constituted of 5000 apartments located in the city of Zaragoza (Spain). The effect of legal constraints in the design and operation of CHCP systems is highlighted in this study.

Abstract Post-industrial societies heavily rely on the consumption of embodied energy for their activities – i.e., energy invested elsewhere to produce what is imported and consumed (or re-exported). The openness of the energy sector poses modelling challenges, calling for multi-scale, integrated analytical frames. We propose a methodology grounded in societal metabolism aimed at analysing the behaviour of a system (where the system may be a region, a country, a continent, etc.). We make the distinction between three types of scales necessary to contextualize the behaviour of the energy sector within a globalized economy: the macroscope, the mesoscope and the microscope. The methodology is applied to analyze the energy sector of EU19 countries, considering internal and external labour, primary energy sources, energy carriers and GHG emissions. The results show that imported primary energy sources and energy carriers within the EU19 are associated with externalized pressures and impacts. For example, accounting for the externalized carbon emissions of the energy sector raises total GHG emissions of the sector by 60% on EU average. This has implications for the assessment of the effectiveness of global sustainability policies. By not accounting for externalized effects, energy models can miss relevant information about the interactions among systems.