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This research presents a scenario for a 100% renewable energy system for the City of Cuenca, Ecuador, with a projection to the year 2050. The transition process starts with Ecuador’s change in the productive matrix with reforms from the legal and business strategies point of view to the year 2050. Advances in energy material are dependent on political uncertainty both at the country (Ecuador) and local (Cuenca) levels. It is possible to stop using fossil fuels due to the implementation of new renewable energy sources, potentially rich in the Ecuadorian Southwest and evidenced in the National Plan for a Lifetime. Currently, there is evidence of accelerated changes concerning legal regulations, including the construction of several electric power generation plants. This change in the national productive matrix implies, among others, the implementation of electric vehicles and the change of natural gas stoves for electric ones, and the implementation of the “4 Rios” tram that crosses the city from North-South and South-North, incorporating 100% renewable energy generation, which would provide heat in urban and marginal urban areas. All the systems created in Ecuador, such as heating, cooling, transportation, security etc., will allow an increasing penetration of renewable energy until it reaches 100%.

The use of low-impact energy sources is gradually growing with the aim of reducing greenhouse gases emission and air pollution. The alternatives offered by geothermal systems are one of the key solutions for a future renewable development, enabling the electrification of heating systems and the use of biofuels. This research addresses an overview of geothermal heating systems using ground source heat pumps in different European countries. Besides the traditional electrical heat pumps, gas engine heat pumps aided by natural gas or biogas are analysed in three areas. From a previous research, the technical parameters defining the geothermal system are used here to evaluate the most appropriate system in each scenario. The evaluation of different influential factors (operational costs, initial investment, environmental impact, and availability) allows defining the most recommendable systems for each area. Results of this multi-parametric study show that gas engine heat pumps aided by biogas could mean an excellent solution in all countries, also contributing to the management of waste and polluting substances. If biogas systems were not available, the electrical heat pump would be the first option for areas 1 and 3 (Italy and Sweden) but not for area 2 (United Kingdom), where natural gas is preferred.

The combined cycle plants in 2019 are upswing due to definitive closure of conventional coal-fired power plants. The price increase of a ton of CO2, will close to 25 euros in 2019, could allow to increase their capacity factor above 50%. It has been already achieved a high flexibility imposed by the regulator of the Spanish network and possible hybridizations, in both gas turbine and heat recovery steam generator. Therefore, one step ahead directed to the reduction and treatment of the flow of exhaust gases at the outlet of the boiler during the operation is necessary. An optimization study based on a parametric analysis of this possible reduction has been carried out, with recirculation of the exhaust gases and the treatment of them with amines in a CO2 capture plant, both at the exit of the boiler, using real data base, to study their possible integration within the existing combined cycle. The results obtained are very promising: firstly, with the use a 35% of exhaust gases recirculation + capture plant in existing combined cycle, the efficiency of the gas turbine improves 0.5%. Secondly, the total number of tons of CO2 avoid per year would be around 633 kilotons (based on a capacity factor in 2019 closed to 0.41). Therefore, the saved cost in ton of CO2 for one existing combined cycle could be around 21.4 million of euros/year. This configuration, therefore, decreases the number of trains from 2 (existing combined cycle + capture plant) to 1.36. This decreasing is traduced in costs reduction and due to it an effective technique for pollutant emissions reduction. On the other hand, the new combined cycle will have an efficiency penalty caused by chemical absorption in the capture plant. The crossover requires approximately 30% of the middle/low steam of the turbine to obtaining 90% capture of CO2 with the corresponding penalty of 4 points in the global cycle performance and a reduction of power close to 21% with respect to the existing cycle. All boil down to a conflict of interests between €/Mw lost vs €/ton CO 2 avoided. Clearly the rising in capacity factor and flexibility in current combined cycle plants will be decisive in future to elucidate this conflict. The results obtained are totally in contrast with other studies carried out being fully feasible for implementation in existing combined cycles.

Climate change conditions in the last decades have derived in a significant reduction of rivers’ levels, irregularity of rainfall and, thus, difficulties in accessing to drinkable water. This situation is especially dramatical in islanded environments, such as the Canary Islands in Spain, where these restrictions to water resources have conducted to an overexploitation of aquifers and wells, with the deterioration of the environment that this fact entails. For this reason, desalination plants have become essential, and efforts must be done to reduce their impact and costs, as the involved processes for water desalination are high energy intensive. In this research paper, an optimized size hybrid wind and solar photovoltaic power plant is proposed to feed a desalination plant under the approach of not only feed the desalination process, but also provide the power grid with clean energy, taken advantage of the surplus electricity production. This way, not only the water resources stress is mitigated (through the desalting water production), but also the grid benefits from the integration of a distributed renewable energy source (DRES). Moreover, the business model is improved as the cost of drinkable water production is reduced and the power plant owner receives extra incomes from the water sales. Optimization results for a case study in Gran Canaria island shows that, considering the power dispatch in the island, the remuneration limits for power delivery and the remuneration for provided water, the optimal DRES associated with a desalination plant providing 5600 m3/day of desalted water and a maximum annual electricity injection to the power grid of 5.88 GWh/year, an hybrid solar PV and wind generation installation with electrochemical storage is a feasible solution that makes the Levelized Cost of Electricity (LCOE) achieve a singular reduced value despite considering the additional costs of the desalination plant, although financial help must be provided to reduce the Payback Time. Keywords: Water stress, Desalination, Renewable energy, Solar photovoltaics, Wind energy, Hybrid power plant

This research reviews the technical requirements of grid-connected photovoltaic power plants to increase their competitiveness and efficiently integrate into the grid to satisfy future demand requirements and grid management challenges, focusing on Spain as a case study. The integration of distributed resources into the electric network, in particular photovoltaic energy, requires an accurate control of the system. The integration of photovoltaic energy has resulted in significant changes to the regulatory framework to ensure proper integration of distributed generation units in the grid. In this study, the requirements of the system operator for the management and smart control are first analysed and then the technical specifications established by the network operator in reference to the components of the facility are evaluated. This analysis identifies the shortcomings of the current legislation and concludes with a summary of the main technical recommendations and future regulatory challenges that need to be undertaken in the future. It is presented as a reference case that can be adapted worldwide.

Exergy is the very useful tool to evaluate energy systems besides energy analysis based on the first law of the thermodynamics. In contrast to energy, exergy is not conserved and always decreases. There are many types of exergy analysis involving exergoeconomic, exergoenvironmental, advanced exergy-based analyses, extended exergy analysis etc. In this study, an application of the extended exergy analysis is performed. In extended exergy analysis, not only energy related system is considered but also all materials and energy flows’ exergy, non-energetic and immaterial fluxes (capital, labor and environmental impact) are turned into exergy equivalent values and utilized in the analysis, which are calculating for local econometric and social data. These methods can be applied to societies or energy based or non-energy-based system. In this study, dynamic exergy analysis and extended exergy application of electricity generation from photon enhanced thermionic emitter is conducted. According to results, some important values can be listed as; extended exergy destruction, conventional based exergy destruction, extended exergy efficiency, conventional exergy efficiency, extended sustainability ratio, conventional sustainability ratio, extended exergy-based depletion ratio and conventional exergy-based depletion ratio are 542106006 MJ, 542084601 MJ, 0.01094, 0.01094, 1.011, 1.011, 0.978 and 0.989 respectively.

Energy consumption in the transport sector and buildings are of great concern. This research aims to quantify how eco-routing, eco-driving and eco-charging can increase the amount of energy available for vehicle-to-building. To do this, the working population was broken into social groups (freelancers, local workers and commuters) who reside in two cities with different climate zones (Alcalá de Henares-Spain and Jaén-Spain) since the way of using electric vehicles is different. An algorithm based on the Here® application program interface and neural networks was implemented to acquire data of the stochastic usage of EVs of each social group. Finally, an increase in the amount of energy available for vehicle-to-building was assessed thanks to the algorithm. The results per day were as follows. Owing to the algorithm proposed a reduction ranging from 0.6 kWh to 2.2 kWh was obtained depending on social groups. The proposed algorithm facilitated an increase in energy available for vehicle-to-building ranging from 13.2 kWh to 33.6 kWh depending on social groups. The results show that current charging policies are not compatible with all social groups and do not consider the renewable energy contribution to the total electricity demand.

This work describes a methodology to quantify the benefits from both a business-related and energy resilience perspectives provided by a microgrid based on photovoltaic solar energy and electrochemical energy storage integrated in large buildings, such as office buildings not open to the general public, which is presented as case study. First it has been identified how, by using distributed renewable energy sources (in particular, photovoltaic solar energy) and electrochemical energy storage systems, the life-cycle cost of the energy in a microgrid connected to the electrical network can be reduced significantly. As novel approach, it has been evaluated how this microgrid design can increase the resilience of a power customer supply, quantified as the time period the microgrid is able to feed an electrical consumer at an outage, which it results of great importance for large office buildings that are used to have several critical loads, such as data servers and data processing centers. It was found that, by adding photovoltaic solar energy and electrochemical storage, it is possible to extend the power resilience of this sort of power customers achieving an average survival time to a power cut of 4 h thanks to the proposed solar photovoltaic and energy storage system. Then, the microgrid could save $ 112,410 in energy over the 20-year life cycle of the facility, while increasing the amount of time it can survive a power outage. The proposed methodology presented in this paper provides a model that can be applied to other case studies and scenarios where an alternative to the classic diesel-based emergency supply systems are needed.

The current EU 2020 reference framework has set a 20% goal for energy coming from non-exhaustive resources. In general, it can be said that the national action plans for renewable energy sources and the biennial control provided in Directive 2009/28/EC, regarding the promotion of the use of energy from renewable sources, have been adequate in encouraging clarity for venture capitalists and other stakeholders and, thus, have favored a rapid development of renewable energy from 10.4% in 2007 to 17% in 2015. Between 2005 and 2013, the Spanish government implemented a renewable aid plan that induced an important boost in the number of wind energy projects facilitated by companies. This scheme was modified in 2013, resulting in a drastic decrease in the investments on wind energy capacity. The reason that this regime was modified not only because of the worldwide economic downturn since 2010 but also owing to the shortcomings of this scheme. The expected venture capitalist behavior with respect to the current energy regime is still uncertain. Given the limited support provided by the Spanish government, any remarkable development seems unlikely. This research suggests that a sudden change in the decreased investments on wind energy capacity is unlikely and the wind energy targets for 2020 will not be achieved if no new policies are implemented.

Despite the Spanish privileged geographical location and business leadership in the renewable energy field, currently is can be observed that the solar photovoltaic generation, electric self-consumption systems and net-metering policies deployment is much lower than it can be observed in other countries, even with lower energy sources for self-consumption. Energy policy experts assess as main reason the absence of a stable regulatory framework and the existence of clear disincentives. These disincentives are based on several economic non-market failures and institutional barriers. One key factor has proven to be the regulatory uncertainty created mainly by the recent national most relevant ministerial orders regarding energy generation and consumption, which suggests that, de facto, the regulatory framework is currently still under development. This paper includes first a brief but deep description of the prosumers penetration existing scenario in Spain, and then it focuses on feasible strategies to accelerate higher solar photovoltaic and self-consumption growth rates in Spain. Then, new policy measures to eliminate, or at least, mitigate, current barriers to their deployment are proposed and discussed. It is concluded that it results mandatory the urgent modernization of the energy regulatory framework promoting an active role for distributed PV generation which could have a significant positive impact in the voltage control and frequency regulation in distribution networks, among other advantages.

Sanitary-ware industry, as a sub-sector in the ceramic industry, is a great consumer of energy and water, although there are some opportunities to reduce the global consumption, especially for factories based on resin molds technology. This research aims to show the way to reduce drastically water consumption by recovering waste heat into a multi-effect distillation system to re-use most of the flushing water. This solution improves both, the environmental and economic performance of this industry. The proposed configuration is a multi-effect distillation (MED) adapted to run with recovered heat from the kiln exhausting. The efficiency of the system is improved by recovering the heat of the gas mixture leaving the first effect in the pre-heater of the feeding water. The research lays on the computerized simulation of the coupled systems run under different parameters. Mathematical and thermodynamic models have been developed to simulate the behavior of the system. The obtained results show the optimal configuration depending on the thermal variables which could achieve up to almost 92% of the needed water against conventional technology. The system can be applicable to new or existing factories based on resin molds technology and this research may contribute to reduce consumption of resources and thus, the environmental impact.

One possible contender to replace conventional reverse osmosis schemes is an energy solution where inexhaustible resources work together with a reverse osmosis plant. Based on the experience of an existing wind-powered desalination scheme run for more than 15 years by Soslaires Canarias S.L., the final objective of this paper is to propose improvements to the scheme so as to achieve a reduction in the cost of water (through restrained capital expenses) for the sake of greater feasibility and efficiency. The cost of the scheme is evaluated assuming a combined use of a reverse osmosis desalination plant and wind energy, using, for this purpose, the (exclusive) information provided by the industrial partner. Results showed that by carrying out the actions suggested in this paper, this scheme would be able to reduce its cost of water (COW) by about 0.022 EUR per cubic meter for the current LCOE of wind turbine technology in the study area (about 6 c€/kWh for the southeast of the island of Gran Canaria, Spain). This would mean that with an additional total capital investment cost of 196 000 € (from the current scheme of Soslaires Canarias S.L.), and supposing an average membrane life expectancy of 10 years for the current state-of-the-art membranes, a net present value of 74 360.95 €, a profitability index of 1.3794, and a 224.4881% internal rate of return would be achieved.

The latest revisions in April 2018 of the 2010/31/UE and 2012/27/UE Directives on Energy Efficiency and Energy Savings respectively, point out the need of the development of smart energy indexes for buildings with the aim to (i) supervise the energy consumption on the building sector -that currently represents up to one third of the total final energy consumption- and (ii) lead the appropriate actions to transform the current buildings stock to nearly Zero Energy Buildings and Positive Energy Buildings. From public managed buildings, the Health System is the first energy consumer with great difference with other government administration sectors, such as Education or General Administration. Moreover, the energy bill has great impact on the sustainability of the public health care system. However, very few real data were available to characterize the energy demand on public buildings, which are usually the most intensive energy consumers, and efficiency indexes were usually obtained from simulation results. Nevertheless, thanks to the deployment of Smart Metering systems in the last years, it is possible to access to the true energy demand profiles of hundreds of these buildings. In this paper, with three years historical monthly electrical energy consumption data from the health system of the region of Castilla y Leon in Spain -including hospitals, outpatient facilities, clinics and other medical institutions- and the application of data mining techniques, an end-use electrical energy analysis was conducted to cluster the building housing according to the energy consumption into several energy use intensity clusters and, then, an average value and a Reference Building Energy Index for each cluster is proposed. Thus, a true energy labeling of these buildings based on their distance to the Reference Building Energy Index is done and presented in georeferenced maps.

Sanitary-ware manufacturing has a specific particular configuration of energy consumption from the thermal point of view. Heat requirements and temperature levels through the different sub-processes in the manufacturing sequence are distributed in such a way that a proper network of recovered heat can save up to 1/3 of the primary energy consumption of the factory. A half of the total thermal requirement is devoted to fire the ware along a tunnel kiln that exhausts ¾ of this heat through the exhausting and cooling stacks at a temperature a proper temperature level to be recovered in the rest of common thermal processes as drying or heating. On the other hand, the great water consumption to flush resin molds can be saved by a multi-effect distillation treatment fed with recovered heat. Instead of rejecting it with solved salts, a combined power plant optimally sized can be coupled to match both, electrical and thermal consumptions allowing for extra heat to distillate the flushing water. This research shows how sanitary-ware manufacturing can be re-engineered to save most of the water and 31 percentof primary energy

Most countries in Europe are going under a significant transformation process from carbonized power energy sources to renewable and sustainable ones to feed their increasing demands. European Union targets on its energy roadmap states that by 2030, a reduction of 40% of CO2 emissions regarding the 1990 levels must be done and full transition must be completed by 2050. Thus, EU member countries, such Spain, are carrying out lots of investments to transform their power generation structure by promoting the installation of renewable energy power plants, with a significant visual and environmental impact. In the case of Spain, it is planned that, by 2030, 27% of final power consumption must be renewable, with approximately 31 GW of installed wind energy (8 GW must be installed in the next 10 years). Wind energy is supposed to be one of the generation leaders in this transformation context due to its high performance, high availability and fast decreasing costs. Nevertheless, wind farms have been installed on-shore with great success since the decade of the 90s covering the locations with the best wind resource. Thus, many of the installed wind turbines have overcome the half part of their expected lifespan and their payback periods, but the learning curve of the wind energy technology has improved exponentially since then. This paper is focused on the true valorization of an existing wind farm and the efficacy of the exploitation of the site’s wind resource. A novel repowering decision support model based on the opportunity cost analysis between repowering the current wind farm with the latter technologies and full depletion of the wind farm is proposed and applied to the Spanish Iberian Peninsula case study. Results show that the repowering option is significantly attractive in most cases and its proper application could have, not only a positive environmental effect, but also an economic impact on the sustainability of this source of energy.

In this research, the modeling, simulation, and analysis of the energy conversion equations that describe the behavior of a hybrid photovoltaic and wind turbine system that supplies electrical energy to an average organic architecture is performed. Organic constructions have a philosophy that seeks to understand and integrate into the site, taking advantage of the natural potentials and their resources of the surrounding areas so that they form part of a unified and correlated composition. The rooms in these buildings are designed similar to a bean, inspired by the uterus of a mother and her child who are comfortable, at rest, and alive. We are left with the task of spreading this research to integrate its energy potential from the surroundings and transform it into autonomous electrical energy. In this article, a numerical model based on the fundamental equations was developed and coded, and the results compared with experimental data with a real airplane-type system located in a remote area of Ecuador. The model is intended to be used as an optimization and design tool for such hybrid systems applied to organic constructions. After an error analysis it was determined that this model predicted quite interesting results compared to the experimental data under various conditions. It is important to indicate that this analysis has been carried out so that in the future, these power generation systems can be exploited and applied more efficiently in areas far from the public electricity grid.

Over the years the ceramic industry has been widely studied. However, little attention has been devoted to the particular area of sanitary-ware manufacturing, although it is a great consumer of energy and water. The aim of this research is to analyze and quantify how and where energy and water are consumed by mapping the whole process. Once the key points and amounts of consumption are located, a global map of single flows is established by thermodynamically modeling every relevant sub-process as a balance of mass and energy. The research focuses on demonstrating that this modeled map can be optimized by diverting energy flows from one sub-process to another searching for the minimum incoming energy within the global process, which derives in a minimization of residual energy, waste water and emissions. Results show that almost one third of the energy and emissions can be saved and more than a half of the water can be saved as well in the resin mold technology of manufacturing. This research provides a tool to know how the resources are consumed in the sanitary-ware industry and show the possibilities to reduce them as well as the global impact.

Sustainable energy development in the farming sector is an essential strategy to respond the combined challenge of achieving a reliable and affordable solution but including mitigation and adaptation to climate change. Intensive breeding farms require maintaining an adequate indoor thermal environment that results in high energy demands, usually covered by fossil fuels and electricity. This paper addresses the application of the combined slurry technology for a particular pig farm that currently uses a diesel boiler to supply the piglet heating energy needs. The study also considers different options based on closed ground source heat pump systems. After the design of the slurry alternative and the geothermal ones, notable advantages are detected compared to the existing diesel system. Results show that the implementation of the slurry technology implies an important reduction of the operational costs, which, in turn, involves short amortization periods for this system in relation to the diesel one. Greenhouse gases emissions are also highly reduced in the slurry alternative based on the low electricity use of the heat pump. The environmental side is reinforced by the reduction of polluting substances such as methane of ammonia derived from the descent of temperature of the slurry.

This paper describes the integration of the pico turbines in the drinking water network of the city of Las Palmas de Gran Canaria (Spain). World's drinking water supply companies need updates his infrastructure and technology to turn existing networks into smart water networks, to preserve people's health by ensuring the potability of water for human consumption. The essential parameters for water quality (such as chlorine level, pH, turbidity and others) can be easily measured using sensors inserted in the pipes and in the storage and distribution tanks. Access to this information in real time and immediate action is essential to ensure the health of the people who access this vital element. It is therefore essential to increase the number of sensors and the analysis of the data they provide in order to detect anomalies, correct them and anticipate their consequences. Some of the objectives are the correct measurement of meters to detect leaks and anomalous consumption, saving water and energy, avoiding water and air pollution, achieving efficient supply to the consumer and achieving profitable, efficient and environmentally sustainable urban hydraulic systems. All systems require power, the pico turbines inserted in the network can supply power without affecting the normal operation of the network. Pico turbines are highly efficient, low cost and easy to install systems, but they are not widely used. The case exposed in this city could be replicated in many urban systems, it is novel that there is no literature of massive applications, existing a wide capacity of implantation and development of this technology. When it seems that the locations for the installation of hydroelectric plants have been exhausted, it is time to commit to the development of this mature technology on the micro-scale of the infrastructures already created, the novelty is to continue discovering those places where there is untapped energy potential. There is capacity to grow in very small hydroelectric systems with immediate profitability. The researchers in this article describe the first phase of an investigation that has gone hand in hand with its validation and actual exploitation. The aim is for managers not to forget this technology, which has a very wide growth field to satisfy the small demand for distributed energy in water networks of all types. The authors hope that the results of the research carried out will motivate other technicians to apply the energy potential of their water networks for the self-sufficiency of their control, remote control, chemical dosage and water analysis systems. The applications they carry out will be immediately profitable.

The European Green Deal aims to make Europe the first climate-neutral continent and reduce greenhouse gas emissions by 2050. This research offers proposals for the European Green Deal based on sustainable transport, clean energy and reduction in the energy consumption of buildings. An algorithm based on the Here® application programming interface, neural networks, data from the Spanish transmission system operator, eco-routing, eco-driving and eco-charging is proposed. Its contribution to vehicle-to-home, renewable energy integration, and vehicle-to-home and vehicle-to-grid compatibility is analysed by using data acquisitions of the trips made by drivers from different social groups. The algorithm allows a daily energy saving of up to 2.2 kWh for freelancers, 1.5 kWh for commuters and 0.6 kWh for local workers. The vehicle-to-home contribution increases from 18 MWh to 553 MWh per year. Finally, neural networks allow better integration of renewable energy. The contributions to the European Green Deal are as follows: energy efficiency improves when policies are addressed to the adequate social sector combined with eco-driving and eco-routing; neural networks allow for achieving a better integration of renewable energies as they can predict when its contribution is higher; and policies to make vehicle-to-grid and vehicle-to-home compatible with reduced emissions must be developed.

Water scarcity and contamination of available water are becoming one of the most complex problems worldwide and they compromise economic development, global sustainability, and human supply, among others. Water is required in almost all human activities and also for planet equilibrium in terms of biodiversity. In this research a new home scaled water desalination plant, using a reverse osmosis technology and driven with solar energy is analyzed via extended exergy analysis, which is one of the most accurate methods for evaluating both energy performance and sustainability. The proposed system, that is presented and analyzed, consists of a solar concentrator having 1000 concentrating rate, a Photon Enhanced Thermionic Emitter, a Dye-Sensitized Solar Cell for the electricity generation and a Reverse Osmosis Desalination Plant (RODP) for water purification using the produced electricity. This system allows water desalination in small scale plants requiring low density energy sources and can produce sustainable water for multiples uses, such as domestic use or agricultural, among others. The most important results are labor and capital exergy equivalents, 42.68 MJ/workhour and 12.09 MJ/Euro, respectively, and an exergy destruction of 389.700 GJ for all the system annually. The proposed technology can be extended and used in different locations and the Extended Exergy Analysis can be used as a powerful tool for both design and optimization.

This paper presents a cost-benefit analysis for the bi-directional functionality of plug-in electric vehicle charging, often called vehicle-to-grid. Plug-in electric vehicles represent an opportunity to reduce emissions from transportation, improve the efficiency, and also, it is a solution for storing electricity from the grid. The research is focused on the vehicle-to-home application for plug-in electric vehicles, which entails a bi-directional energy flowing from vehicles to households. The benefits from this use of the plug-in electric vehicles batteries are peak-shaving as well as valley-filling on the load curve, resulting in cost reductions for the user and the electric power system. In the case of islands, the use of this storage would allow an increased penetration of renewable energy sources and a reduction of costs. The research discusses the impact of vehicle-to-grid for the Canary Islands, where a plug-in electric vehicles penetration charging higher than a 20% would cause changes to the current demand curve peaks. The results show the benefits to both the system operator and the users, which may reduce mobility energy costs by a 50% through the time of usage. Vehicle-to-home regulation based on standards is recommended for incentivizing its functionality, the time of usage pricing, based on market prices, being the most beneficial for the user and the electric power system as a whole.

The penetration of electric vehicles is a key instrument in the operation of smart grids. Their active participation in the electrical system is proposed as a tool to increase security of supply, successfully reducing the large differences that occur between periods of higher and lower electricity demand. This research presents an analysis of the vehicle-to-grid impact in low capacity electrical systems, as in the case of islands, aiming to establish a charge/discharge pattern that facilitates the penetration of electric vehicles in weak grids. In such a way, a comprehensive scenario needs to be assessed in order to obtain significant results to be applied not only in islands and outermost regions but also in scaled systems such as minigrids. To achieve this objective, a theoretical method for the efficient charge/discharge management of electric vehicles is proposed, defined by a multi-objective model based on criteria of mobility and technical requirements. The proposed model is applied to the island of Tenerife, which quantifies the electric vehicle penetration in a real case. The results show that grids in islands can assimilate “low” or “transition” penetrations of electric vehicles, so their use as storage systems allow to significantly reduce the amplitude difference between valleys and peaks of the electric energy demand curve and thereby to contribute to the efficient management of smart grids.

Water scarcity is a real problem that affects directly over one third of the world population, and greenhouse gases only worsen the situation. Due to this, action must be taken against the overexploitation of resources. Water accounting and saving should be mandatory for a proper sustainable industry. In this regard, the sanitary ware industrial sector, as an intensive consumer of water, should make a social commitment to contribute to stopping water overuse. Sanitary ware manufacturing delivers an amount of water equivalent to the half of the total production weight via evaporation. The aim of this research was to find a green process to reuse the evaporated water and thereby reduce the overall water consumption level as well as promote a cleaner technology with low environmental impact. The key point in supporting sustainability restriction is to match water condensation with heat recovery to avoid any energy surplus. The thermal energy recovered from kiln exhaust gets transferred into a cold flow, which condenses the evaporated water by an absorption cycle. Computational modeling was used to thermodynamically analyze and optimize the performance of this novel technology. The proposed model was applied to the most extended technologies to reduce natural gas usage by 25% and total water usage by 16%. Besides, the surplus of condensed water from combustion and from air moisture has been quantified to be added to savings. The present research provides a practical tool for the sector to use in designing more efficient, green manufacturing plants while supporting a more sustainable business model. It demonstrates and quantifies the potential of water saving in the sanitary ware industry, which had never before been tackled.

Grid connected energy storage systems are expected to play an essential role in the development of Smart Grids, providing, among other benefits, ancillary services to power grids. It is therefore crucial to design and develop control and conversion systems that represent the key instrument where intelligence for decision-making is applied, in order to validate and ensure its optimal operation as part and parcel of the electrical system. The present research describes the design and development of a battery energy storage system based on an AC-DC three-phase bidirectional converter capable of operating either in charge mode to store electrical energy, or in discharge mode to supply load demands. The design is modelled with MATLAB® Simulink® environment in order to evaluate the performance during load variations. Moreover, the assessment is complemented by a global sensitivity analysis for variations in the operating parameters set by the transmission system operator. The effectiveness of the simulation is confirmed by implementing the system and carrying out grid connection tests, obtaining efficiencies over 98% for values over the 30% of the bidirectional converter rated power.

Offshore wind energy generation has experienced an important growth in the last five years, reaching currently an installed capacity of almost 8000 MW. The most important references in this type of technology are Denmark, Holland, Sweden, Germany and United Kingdom. In Spain, previsions for technology, have been set at around 750 MW of installed power during the period 2011–2020. However, Spanish coastal features, social opposition to installations near the coast and lack of a stable regulatory environment guaranteeing the investments are factors which are restraining the development of this technology. This paper presents a brief review of the state of the art of offshore wind technology and it describes the most frequently used types of turbines, transmission systems and support structures in Europe. It also presents the current situation and the expected growth of offshore wind power facilities, introducing the characteristics of the operational – and under construction – windfarms. Finally, it analyses particular problems and solutions for its development in Spain which can be extrapolated to countries with similar circumstances.

Yearly, EU-28 conventional thermal generating plants reject a greater amount of energy than what ultimately is utilised by residential and commercial loads for heating and hot water. If this waste heat were to be used through district heating networks, given a previous energy valorisation, there would be a noticeable decrease in imported fossil fuels for heating. As a consequence, benefits in the form of an energy efficiency increase, an energy security improvement, and a minimisation of emitted greenhouse gases would occur. Given that it is not expected for heat demand to decrease significantly in the medium term, district heating networks show the greatest potential for the development of cogeneration. However, to make this happen, some barriers that are far from being technological but are mostly institutional and financial need to be removed. The purpose of this review is to provide information on the potential of using waste heat from conventional thermal power plants (subsequently converted into cogeneration plants) in district heating networks located in the EU-28. For this, a preliminary assessment is conducted in order to show an estimate of the cost of adopting an energy strategy in which district heating networks are a major player of the energy mix. From this assessment, it is possible to see that even though the energy strategy proposed in this paper, which is based on a dramatic increase in the joint use of district heating networks and cogeneration, is capital-intensive and would require an annual investment of roughly 300 billion euros, its adoption would result in a reduction of yearly fuel expenses in the order of 100 billion euros and a shortening of about 15% of the total final energy consumption, which makes it of paramount interest as an enabler of the legal basis of the “Secure, Clean and Efficient Energy” future enacted by the EU-28 Horizon 2020.

We are witnessing in recent years a significant increase in the penetration of small units of distributed generation on electricity networks, motivated by a higher demand of environmental protection and a gradual process of liberalization on the energy market. In last decade many countries have begun a liberalization process of their electrical systems by opening access to transmission and distribution networks. This has been accompanied by a fast growth in the presence of small generators distributed, of several technologies, many of them based on renewable energy sources. However, there are still technical, economic and regulatory barriers that limit the definitive boost of distributed generation (DG). The increase of connections in many cases, has been based on the philosophy “fit and forget” and capacity of installed DG remains limited by Distribution Network Operators. In this article are reviewed those factors that can contribute most to the necessary evolution of DG, to overcome the current paradigm of renewable distributed generation sources “integrated in a real network”, and reach a stage of DG units “embedded in the new distribution networks”. To do this, aspects such as, Smartgrids and new information and communications technologies, microgeneration and storage technologies, Active Management Network, multiobjetive planning as an optimization tool for sizing and selection of sites DG, or regulatory issues, are examined along of this article.

The aim of this research it is to show how the biogas biomethanisation from primary and secondary treatment of activated sludge from a wastewater treatment plant (WWTP), can be an alternative renewable energy option from fossil fuels, which offers competitive advantages and points out new horizons for the use of this fuel. This will allow to achieve some important priorities of energy plans in EU countries: to reduce the organic matter deposited in landfills and CO 2 emissions and to find viable solutions to minimize the environmental impact of sewage sludge (SS). This study analyses the biogas combustion and energy recovery processes from a thermodynamic, thermoeconomic and exergetic point of view. The results show that the boiler of the process is the main source of irreversibility and exergy destruction. Moreover, the energy and exergy economic value of exhaust gases from the combustion chamber, are significant and worthwhile to be exploited. For this reason, the present study explores the applicability and suitability of integrating a Stirling engine in such process. The study reveals that it is possible to create a small micro-cogeneration system which leads to sustainable waste management and energy savings in the treatment plant itself.

With a potential geothermal generation of 610 GWt, Spain constitutes a promising EU-28 country for geothermal direct heating systems and binary cycle electricity production. Spain has a need to reduce energy consumption in buildings and in the secondary sector in order to comply with the Spanish Energy Plan 2011–2020, which establishes an objective of 50 MWe of electricity generation from geothermal energy and 66 MWt for direct heating use. Geothermal pumps are admissible in low and medium temperature heating schemes, but to achieve these energy savings targets, the most interesting way to generate energy is by using a CHP production from binary cycle plants. An analysis determining the energy consumption for Spanish dwellings shows that with a low-temperature design concept for district heating distribution, an organic Rankine cycle plant of 15 MWt with a geothermal temperature supply of 105 °C and a vector transportation fluid mass of 100 kg/s can cover 3% of the expected targets of electricity from geothermal sources and 15% of that expected for direct heating.

The purpose of this paper is to prove as possible the improvement of the efficiency of a photovoltaic power plant, if it could be installed on top of a water canal, and how this facility could at the same time improve the efficiency of the water canal. The Tajo-Segura water transfer located in Spain has been chosen as the scenario for this research paper. The use of a water canal for this type of photovoltaic facility involves several problems. For example, it is very important that under no circumstance should any change on the canal structure affect the main end-use purpose of the hydraulic infrastructure (to channel water). Moreover, these facilities are strongly linear structures, so there is a problem connecting the electricity to the network. Nevertheless, these problems could be solved or minimized by applying different technical solutions, and if optimal synergies between infrastructures were obtained. It should be taken into account that the water facilities, which are already on service, save a significant quantity of water, and that these savings are achieved while avoiding the evaporation produced by direct solar radiation. The facility in this study can increase its efficiency, thanks not only to the optimal positioning to avoid the shadow between panels but also because panels can be cooled with the water that the canal contains. Focusing on these improvements, different types of technology implementation have been studied, concluding that the best option is the fixed system technology. A special methodology to geometrically place the photovoltaic panels has been developed. A proposal for novel cooling is also included in this work. The results of this study show that the project could be developed with an investment of 248 M€. Through the power generation and the savings in canal water resources, the investment could be repaid in approximately 15 years. The contribution of this work is the demonstration of the technical and economic interest of the optimal configuration analyzed.

This research work aims at a multinational study in Europe of the emissions and energy costs generated by the operation of low enthalpy geothermal systems, with heat pumps fed by different energy sources. From an economic point of view, natural gas and biogas prices are, usually, lower than electricity ones. So it may be advantageous to use these energy sources to feed the heat pumps instead of electricity. From the environmental point of view, it is intended to highlight the fact that under certain conditions of electricity production (electricity mix), more CO2 emissions are produced by electricity consumption than using other a priori less “clean” energy sources such as natural gas. To establish the countries where each of the different heat pumps may be more cost-efficient and environmentally friendly, data from multi-source geospatial databases have been collected and analyzed. The results show that in the majority of cases, the electric heat pump is the most recommendable solution. However, there are some geographic locations (such as Poland and Estonia), where the gas engine heat pump may be a better alternative.

This article examines the main market barriers that hamper the introduction of geothermal energy at local, national, and European levels as well as the necessary steps that need to be taken to eradicate them, thus contributing to the general use of this renewable source of energy. The novelty of this study lies in the detailed description of four different scenarios: the European Union (EU), Spain, the Canary Islands, and the agricultural sector for the three types of geothermal energies and their uses: Low-enthalpy or thermal uses, high-enthalpy or electrical uses and renewable energy mix. The results are expected to differ in terms of level of introduction, barriers, and measures to be taken. We have selected Spain within the European context due to its meagre 0.1% geothermal market share in primary demand for renewable energy, and the Canary Islands in particular, given its insular nature. We have likewise picked the agricultural sector due to its underdevelopment as far as renewable energies are concerned, including geothermal energy.

The purpose of this paper is to assess the economic impact following as a result of the conversion of conventional stations to cogeneration plants connected to a system for distributing heat and refrigeration. The analysis will be carried out through a financial evaluation in order to assess yearly variations of the whole scheme expenditure. In particular, yearly capital and operating costs of supplying cold and heat to urban areas that represent weather conditions in northern, central, and southern Europe were studied. In the base case scenario, today conditions are represented; they will be compared with alternative scenarios in which existing conventional thermal power stations will be converted into cogeneration plants. This research work contributes to the pool of existing knowledge by giving a (so far not addressed) weather centered system perspective. From the conducted evaluation, it was found that, in the case of deciding to convert the studied conventional thermal plants into cogeneration plants, investing in the necessary infrastructure associated means that yearly expenses for the power plants located in Oldenburg-Wilhelmshaven, Bristol, and Cartagena would decrease by 215, 89, and 192 million euros respectively, making this technology a highly attractive option from economic, energetic, and environmental perspectives.

[EN] Yearly, EU-28 conventional thermal generating plants reject a greater amount of energy than what ultimately is utilised by residential and commercial loads for heating and hot water. If this waste heat were to be used through district heating networks, given a previous energy valorisation, there would be a noticeable decrease in imported fossil fuels for heating. As a consequence, benefits in the form of an energy efficiency increase, an energy security improvement, and a minimisation of emitted greenhouse gases would occur. Given that it is not expected for heat demand to decrease significantly in the medium term, district heating networks show the greatest potential for the development of cogeneration. However, to make this happen, some barriers that are far from being technological but are mostly institutional and financial need to be removed. The purpose of this review is to provide information on the potential of using waste heat from conventional thermal power plants (subsequently converted into cogeneration plants) in district heating networks located in the EU-28. For this, a preliminary assessment is conducted in order to show an estimate of the cost of adopting an energy strategy in which district heating networks are a major player of the energy mix. From this assessment, it is possible to see that even though the energy strategy proposed in this paper, which is based on a dramatic increase in the joint use of district heating networks and cogeneration, is capital-intensive and would require an annual investment of roughly 300 billion euros, its adoption would result in a reduction of yearly fuel expenses in the order of 100 billion euros and a shortening of about 15% of the total final energy consumption, which makes it of paramount interest as an enabler of the legal basis of the “Secure, Clean and Efficient Energy” future enacted by the EU-28 Horizon 2020., We are grateful to the experts contacted who gave us their support, in particular and especially to Poul Alberg Østergaard (Aalborg Universitet), Capezzali Massimiliano (École Polytechnique Fédérale de Lausanne), Kevin Sartor (Université de Liège), Erwin Cornelis (VITO NV), Chiara Wolter (Ambiente Italia), Alexandra Tudoroiu (COGEN Europe), Olu Ogunbadejo (Department for Environment, Food & Rural Affairs), Aleksandrs Zajacs (Riga Technical University), and Carsten Magass (Forschungszentrum Jülich GmbH). Without their participation, this article would not have been possible.