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The greater challenge that researchers address and indicate while investigating about photovoltaic (PV) system failures during their Operation and Maintenance (O&M) is the lack of accessible reliable real quantitative data. For this reason, several publications have focused on this problem through a qualitative approach. However, this fact is one of the greater strengths of this paper, in which the quantitative information from the historical data of sixty-three PV plants portfolio in Italy and Spain has been accessible. Results obtained from the research provide essential information for main players involved in PV plants to identify failure modes and rates, in order to reduce investment risk and to focus their maintenance efforts on preventing those failures, improving longevity and performance of PV plants. The paper presents failure rates per PV Site and per kW, considering all portfolio and dividing it regarding five PV plants groups per size, distribution of failures per element, Mean Time Between Failures (MTBF), reparation times per affected element and the main failures modes examining each of the almost 100,000 complete alarms registered during the five years analyzed. • Failure rates and modes analysis of photovoltaic plants.. • Historical failures data and photovoltaic operators' perspective analysis.. • Review of failures frequencies in photovoltaic plants.. • Photovoltaic failure rates for its application in FMEA analysis. [ABSTRACT FROM AUTHOR]

This paper explores whether the changes in energy intensity in Spain have led to improvements in the energy consumption levels or to a backfire effect offsetting the expected decrease. Jevon's paradox or backfire effect happens when a rebound higher than 100% causes energy efficiency improvement to raise energy consumption. To test Jevon's paradox or the backfire effect caused by energy efficiency actions, a Logarithmic Mean Divisia Index I (LMDI-I) is used for the Spanish economy. The period under consideration ranges from 2000 to 2015, when three national action plans were implemented. The main methodological novelty of this paper consists on to block the economic activity effect in a second decomposition round to better explore the effect of energy efficiency on energy consumption. As a whole, our results do not support Jevon's paradox for the sectors analyzed. However, they do warn about a possible backfire effect in the industry, transport and service sectors. Major findings follow these same findings when the activity effect is blocked. • Backfire effect caused by energy intensity is explored. • Focus is on the Spanish case from 2000 to 2015. • Main methodological novelty is to block the economic activity in a LMDI approach. • Results do not support Jevon's paradox for the sectors analyzed. [ABSTRACT FROM AUTHOR]

This paper describes the construction and analysis of a disaggregated input-output model and its extension to a social accounting matrix (SAM) for the Spanish economy in 2013. Our focus is the specific disaggregation of the electricity industry into the generating, transmission, distribution and marketing businesses, which were decoupled in 1997 under legislation prohibiting any single company from conducting more than one of them. The multi-sectoral framework also allows disaggregation of electricity generating by production technologies (wind, nuclear, conventional thermal, hydropower, solar and other technologies). To the best of our knowledge, this is the first paper in which this information is presented in a multi-sectoral framework for the Spanish economy, which is enormously dependent on the electricity industry. The structural analysis reveals the industry's role in Spain and the importance of its activities. None of the electricity generating businesses is a Rasmussen key sector, and generating and distribution are both capital-intensive activities. Meanwhile, conventional thermal and hydropower generating together make up more than 50% of total output in value terms, while nuclear power accounts for only around 7%. Finally, imports and exports of electricity are small, and almost all demand is covered by domestic production. [ABSTRACT FROM AUTHOR]

Marine renewable energies can play a key role by reducing the dependency on fossil fuels and, therefore, mitigating climate change. Among them, it is expected that wave energy will experience rapid growth in the upcoming decades. Thus, it is important to know how wave climate will change and how suitable the wave energy converters (WECs) will be to the new wave conditions. This paper aims to evaluate the capability of four different WECs—a WaveRoller type device (WRTD), Atargis, AquaBuoy and RM5—to extract wave energy on the Northwest coast of Spain (NWCS). The analysis was performed using the high-resolution wave data obtained from the Simulating Waves Nearshore (SWAN) model over the near future winters (2026–2045). The energy output (P E), the power load factor (ε), the normalized capture width (NC w) and the operational time (OT) were analyzed. According to these parameters, among the devices that work for intermediate-deep waters, Atargis would be the best option (P E = 1400 ± 56 kW, ε = 55.4 ± 2.2%, NC w = 35.5 ± 4.1% and OT = 84.5 ± 3.3%). The WRTD would also be a good option for shallow nearshore areas with P E = 427 ± 248 kW, ε = 12.8 ± 7.4%, NC w = 48.9 ± 9.6% and OT = 88.7 ± 18.9%. A combination of Atargis and WRTDs is proposed to make up the future wave energy farms on the NWCS. • Dynamical downscaling using SWAN to simulate near-shore wave conditions. • Wave energy converters suitability is analyzed in the context of climate change. • Atargis is the most suitable device to future sea conditions in intermediate waters. • WaveRoller type devices can constitute future wave farms for shallow waters. [ABSTRACT FROM AUTHOR]

This paper studies the realizability and compatibility of the three CEP2020 targets, focusing on electricity prices. We study the impact of renewables and other fundamental determinants on wholesale and household retail electricity prices in ten EU countries from 2008 to 2016. Increases in production from renewables decrease wholesale electricity prices in all countries. As decreases in prices should promote consumption, an apparent contradiction emerges between the target of an increase in renewables and the target of a reduction in consumption. However, the impact of renewables on the non-energy part of household wholesale electricity prices is positive in six countries. Therefore, decreases in wholesale prices, that may compromise the CEP2020 target of decrease in consumption, do not necessarily translate into lower household retail prices. Monte Carlo simulations suggest that the probability of achieving CEP's target of reductions in GHG emissions for 2020 is lower than 1% in Austria, Portugal, and Spain. In horizon 2030, Austria, France, Germany, Portugal, and Spain have probabilities lower than 1% of achieving the GHG emissions target. Finland and France present success probabilities lower than 1% on the national targets of renewable sources for 2020 and 2030 as do Austria and Spain with reductions in electricity consumption. • Renewables decrease wholesale electricity prices in ten EU countries in 2008-16. • Renewables increase the non-energy component of household prices in six countries. • Austria, Portugal, and Spain have less than 1% chance of reaching GHG target by 2020. • France and Finland have less than 1% chance of reaching renewables target by 2020. • Austria and Spain have less than 1% chance of reaching consumption target by 2020. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyse the effect of oil price shocks on unemployment in an oil-importing country such as Spain to determine whether they affect unemployment differently in times of financial distress. In order to do so, we use Bayesian methods to estimate a SVAR model with endogenous oil shocks. According to our results, the response of unemployment to oil shocks is clearly different in the pre-crisis compared to the crisis period. Asymmetries are also an important feature of the data: positive oil shocks contributed negatively to the evolution of employment in Spain after the outbreak of the crisis, while any decreases had less of an effect in terms of a recovery in the employment rate. • We analyse the effect of oil price shocks on unemployment in an oil-importing country such as Spain. • The response of unemployment to oil shocks is different during financial distress. • Asymmetries are also an important feature of the data. • Policies need to be implemented to protect against oil prices passthrough to unemployment. • Policies need to be designed so as to allow drops in the oil price to benefit the unemployed. [ABSTRACT FROM AUTHOR]

The energy retrofitting of residential stock is not always straightforward where heritage protected housing is concerned. In southern Europe, many examples built under the Modern Movement codes are now obsolete in terms of energy efficiency. The aim of this paper is to assess the potential for improvement of comfort conditions and energy efficiency in Mediterranean heritage residential buildings, through the incorporation of passive strategies in keeping with preserving heritage values. Long-term monitoring and field tests in representative flats of the case-study building were carried out and, focusing on a single example, adaptive comfort equations were used to assess results. The passive strategies considered are the thermal isolation of the air cavities of walls, changing window frames, optimizing window glazing, and setting up regular mechanical ventilation rates for indoor air changes. Although simulation results generally predict a better energy performance after testing retrofit strategies, the potential decrease in energy demand is more noticeable than the potential improvement in comfort conditions. • The improvement of comfort and energy efficiency in a heritage building is assessed. • Long-term monitoring and field tests were carried out in representative flats. • Passive strategies in keeping with preserving heritage values were examined. • Adaptive comfort equations were used to assess results focusing on one flat. • Energy efficiency improvements are more noticeable than those of comfort conditions. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation on the spectral losses of photovoltaic (PV) soiling. The transmittance of a glass coupon exposed to natural soiling outdoors in Jaén, southern Spain, has been measured weekly and used to estimate the soiling losses that various types of photovoltaic materials would experience if installed in the same location. The results suggest that measuring the hemispherical transmittance of the soiling accumulated on a PV glass coupon can give enough information to quantify the impact of soiling on energy production. Each PV technology is found to have a preferred spectral region, or a specific single wavelength, for which the transmittance through a PV glass coupon could be used for the best estimation of soiling losses. Overall, considering the average spectral transmittance between the extreme wavelengths of the material-specific absorption band, or the transmittance of soiling at a single wavelength between 500 and 600 nm yields the best estimations for different PV technologies. The results of this work can lead to innovative approaches to detect soiling in the field and to estimate the impact of spectral changes induced by soiling on PV energy production. Image 1017542 • The transmittance of an outdoor-mounted PV glass coupon was monitored for a year. • Broadband or single-wavelength transmittance can predict the PV panel soiling ratio. • The best single-wavelength estimations are found between 500 and 600 nm. • The average transmittance over the PV material-specific band has a high correlation. • The average transmittance in the visible correlates better than the UV or NIR bands. [ABSTRACT FROM AUTHOR]

This paper addresses the economic and environmental effects of three scenarios of change for the electricity sector in Spain, in line with the European Union targets: (1) to address the low trade with the rest of Europe, increasing the integration with the European network; (2) to enhance environmental sustainability, increasing the use of renewable energy sources, while decreasing the use of brown energy sources; and (3) increasing the competitiveness of the Spanish electricity sector. To this end, we develop a computable general equilibrium model, with 72 productive sectors, eleven of which are energy sectors, where electricity is disaggregated into five production technologies and transmission, distribution, commercialization, and related activities. The model is calibrated on a previously developed input-output table with this detailed disaggregation for Spain for 2013. Our results suggest potential improvements in production and trade, and reductions in CO 2 emissions in scenario 2 are also observed. • We address the effects of three policy scenarios for electricity sector in Spain. • We analyze the effects of increasing trade, renewables, and competitiveness. • We construct and disaggregate a computable general equilibrium (CGE) model. • CGE distinguishes the businesses of the sector and the production technologies. • We found improvements in production and trade and reductions in CO 2 emissions. [ABSTRACT FROM AUTHOR]

Abstract: In this paper the AHP (Analytic Hierarchy Process) and the ANP (Analytic Network Process) are applied to help the managing board of an important Spanish solar power investment company to decide whether to invest in a particular solar-thermal power plant project and, if so, to determine the order of priority of the projects in the company's portfolio. Project management goes through a long process, from obtaining the required construction permits and authorizations, negotiating with different stakeholders, complying with complex legal regulations, to solving the technical problems associated with plant construction and distribution of the energy generated. The whole process involves high engineering costs. The decision approach proposed in this paper consists of three phases. In the first two phases, the managing board must decide whether to accept or reject a project according to a set of criteria previously identified by the technical team. The third phase consists of establishing a priority order among the projects that have proven to be economically profitable based on project risk levels and execution time delays. This work analyzes the criteria that should be taken into account to accept or reject proposals for investment, as well as the risks used to prioritize some projects over others. [Copyright &y& Elsevier]

This paper focuses on the economics of a cross-border transmission interconnector. The domestic spot electricity price is modelled as a stochastic process with mean reversion and jumps; it also includes a deterministic part that accounts for hourly and daily sasonalities along with non-working days. The two domestic spot prices are assumed to be correlated. As an illustration of the approach, we consider the particular case of the interconnector between Spain (an 'electric island') and France. Domestic prices are first calibrated and then used for simulating the stochastic behavior of the price gap between the two countries. In addition, the actual import/export behavior as a function of the price gap is captured by a Tobit model fitted from observed data. This model is then combined with the simulated price gaps to compute a multiple series of hourly prices and exports/imports of electricity through the interconnector. Drawing on these simulations we derive the probability distributions of revenues and expenses from exports and imports, and also some risk measures. According to our results, the economics of this interconector depends on different domestic seasonalities (hourly and daily), the growing trend of the price gap and some stochastic idiosyncrasies. They call for an expanded link. • This paper focuses on the economics of a cross-border electricity interconnector. • Domestic price is a stochastic process with seasonality, mean reversion and jumps. • A Tobit model is estimated to capture trade patterns as functions of the price gap. • Trade patterns and simulated price gaps yield probability distributions of revenue. • Results strongly support expanding the link France ― Spain (an 'electric island'). [ABSTRACT FROM AUTHOR]

Abstract Recent electricity management systems such as Smart Grids and Virtual Power Plants help to better integrate distributed generation renewable resources (RDG), such as photovoltaic, small hydro or micro wind in electricity markets. In this context, an important increase of small-scale power generation technologies is expected in Spain by 2020, according to the Spanish Action Plan for Renewable Energy. This paper analyses the environmental and economic impacts of the massive integration of RDG in Spain for 2020 by using an Input-Output approach. The induced production and employment effects in every sector due to new RDG project investments as well as the CO 2 reductions attributed to a decline in conventional electricity consumption are estimated. The results indicate that investments in RDG based on photovoltaic and small-hydro have the greatest impact on employment generation. The RDG investments will lead to a decrease in emissions of 21.67% in 2020 compared with 2013. The RDG technologies become an alternative to reach a sustainable economic growth in Spain. In future research, a multi-regional input-output model and the study of the links between energy consumption, standard of living and consumption patterns will aid to delve deeper into the relationship between economic growth and the environmental impacts of small-scale renewable technologies. Highlights • RDG will be over half of total installed electricity generation capacity in 2020. • The impact of RDG deployment is quantified on Spanish economy in 2020. • The IO methodology is used to study the environmental and economic impacts. • Photovoltaic and small-hydro have the highest impact on employment generation. • RDG becomes an alternative to reach a sustainable economic growth in Spain. [ABSTRACT FROM AUTHOR]

Abstract: A significant number of islands have been forced to restrict the penetration level of renewable energy sources (RES) in their conventional electrical power systems. These limitations attempt to prevent problems that might affect the stability and security of the electrical system. Restrictions that may apply to the penetration of wind energy can also be an obstacle when meeting European Union renewable energy objectives. As a partial solution to the problem, this paper proposes the installation of a properly managed, wind-powered, pumped hydro energy storage system (PHES) on the island of Gran Canaria (Canary Islands). Results from a dynamic model of the island’s power system show that the installation of a pumped storage system is fully supported in all circumstances. They also show that the level of wind penetration in the network can be increased. These results have been obtained assuming that two of the largest existing reservoirs on the island (with a difference in altitude of 281 m and a capacity of aprox. 5,000,000 m3 each) are used as storage reservoirs with three 54 MW generators. Likewise, the ability of such facilities to contribute to the stability of the system is shown. This type of installation can reduce fossil fuel consumption, reducing CO2 emissions. Moreover, not only can the PHES improve wind penetration level, but it also allows the number of wind farms installed to be increased. Regions with geographically suitable sites and energy problems similar to those on the Canary Islands are encouraged to analyze the technical and economic feasibility of installing similar power systems to the one in this paper. Such systems have an enormous, unexplored potential within the general guiding framework of policies promoting clean, renewable energy. [Copyright &y& Elsevier]

Abstract: This paper proposes the use of a new Measure–Correlate–Predict (MCP) method to estimate the long-term wind speed characteristics at a potential wind energy conversion site. The proposed method uses the probability density function of the wind speed at a candidate site conditioned to the wind speed at a reference site. Contingency-type bivariate distributions with specified marginal distributions are used for this purpose. The proposed model was applied in this paper to wind speeds recorded at six weather stations located in the Canary Islands (Spain). The conclusion reached is that the method presented in this paper, in the majority of cases, provides better results than those obtained with other MCP methods used for purposes of comparison. The metrics employed in the analysis were the coefficient of determination (R 2) and the root relative squared error (RRSE). The characteristics that were analysed were the capacity of the model to estimate the long-term wind speed probability distribution function, the long-term wind power density probability distribution function and the long-term wind turbine power output probability distribution function at the candidate site. [Copyright &y& Elsevier]

Abstract: Physical hydronomics (PH) is the specific application of thermodynamics that physically characterizes the governance of water bodies, i.e., the Water Framework Directive (WFD) for European Union citizens. In this paper, calculation procedures for the exergy analysis of river basins are developed within the WFD guidelines and a case study is developed. Therefore, it serves as an example for the feasible application of PH in the environmental cost assessment of water bodies, accordingly to the principle of recovery of the costs related to water services in accordance with the polluter pays principle, one of the milestones of the WFD. The Foix River watershed, a small river located at the Inland Basins of Catalonia (IBC), has been analyzed. Main results, difficulties, and constraints encountered are shown in the paper. Following WFD''s quantity and quality objectives previously defined, water costs are calculated and the equivalence between the exergy loss due to water users and the exergy variation along the river are also analyzed. [Copyright &y& Elsevier]

Several papers have dealt with methodological and application issues related to techniques for decomposing changes in environmental indicators. This paper aims to decompose changes in electricity intensity in Spanish industry and to explain the factors that contribute to these changes. Focusing on an energy intensity approach based on Divisia indices, we began by reviewing the two general parametric Divisia methods and six specific cases. In order to avoid obtaining significantly different results by using differing methods, all of them have been applied to Spanish data. Also two different disaggregation levels have been taken into consideration. Combined with electricity price analysis, the results of this paper indicate the poor contribution of structural change to substantial reductions in aggregate electricity intensity, and underline the role of innovation, development, diffusion and access to more efficient technologies as main contributors to the reduction of the energy/production ratio. [Copyright &y& Elsevier]

Wind resources are increasingly being investigated as a clean alternative for generating energy. This paper analyses the daily wind speed recorded at 46 automatic weather stations located in Navarre, northern Spain, in 2005–2015. Key points are the surface density of stations and the range of time that ensure a faithful depiction of wind speed together with surface calculations from image analysis and correlation with height. Different statistics were used. Median wind speed at 10 m was low, about 3.3 m s −1 and its interquartile range was narrow, about 2.3 m s −1 . Nearly half the surface shows a median wind speed above 3.0 m s −1 . The method of moments was employed to calculate the parameters of the Weibull distribution. Around half of the surface presented a shape parameter above 2.25 and the scale parameter was above 4 m s −1 for nearly 41% of the region. Although wind resources are not suitable for wind turbine applications in most of the region, since the wind speed is low in low-lying areas, about 12% of the region is suitable for stand-alone applications and, moreover, a substantial part of the region, around 23%, presents satisfactory wind resources for the installation of wind turbines. [ABSTRACT FROM AUTHOR]

Incentives have played a major role in wind power development in Spain, having allowed the country to reach top worldwide positions in terms of wind power penetration but having also contributed to a structural cost-revenue unbalance. Feed-in tariff and premium schemes had been in force in Spain since the inception of wind power until the adoption of an auction-based support framework in 2016. So far, auctions have resulted in no incentives being allocated to any new wind farm. The present paper analyses the historical evolution of wind power support schemes in Spain and assesses the long run impact of the newly adopted policies on the future evolution of wind capacity and system costs through a behavioral stochastic System Dynamics model. Results show that the current lack of incentives will entail limited wind capacity growth, below the goal set in Spain's Renewable Energy Plan 2011–2020. Incentive levels required to meet specific goals in terms of capacity growth and system costs are computed and discussed. [ABSTRACT FROM AUTHOR]

Deployment of Distributed Energy Resources (DER) is already a reality for electricity supply and the debate whether distributed generation is going to replace almost totally or partially the current centralized generation paradigm is currently in place. Technical and economic advantages of DER have been addressed in the literature although regulation has also played a central role in DER deployment. This paper aims at contributing to that debate. Firstly, the advantages of both paradigms are reviewed and the cost recovery problem of the existing centralized related stranded costs discussed. Secondly, an optimization model, formulated to specifically address the discussion comparing both configuration paradigms. Main factors affecting the debate are identified and represented in the model: investment and operation costs, flexibility system requirements, demand response capabilities, building thermal demands, network investments and losses, and access-fee design, among others. Thirdly, a realistic case study, based on Spain, is presented and some qualitative conclusions extracted. Such kind of model is useful to undertake country specific studies either to perform sensitivity analysis revealing the relevance of the factors involved and the direct and indirect relationships among technologies, or to analyze the more efficient system configuration and align regulatory decisions towards it. [ABSTRACT FROM AUTHOR]

In this paper, we decompose a family of energy poverty indices into incidence, intensity and inequality among the poor. When continuous variables such as income are used, it is well known that any income poverty index should take into account these three poverty terms. Therefore, every energy poverty measure should also take into account these three. We propose to follow an analogous idea to decompose a family of energy poverty indices in these three components. The novelty of this proposal is that the multidimensional family of energy poverty measures is applied to multiple dichotomous variables and not to a single continuous variable, when, to date, no decomposition has been proposed based on these types of variables. We then extend this decomposition to a further decomposition by population subgroups. In this way, we will be able to know more precisely the origins of energy poverty in order to implement more specific anti-poverty policies targeting the incidence, intensity or/and inequality among the energy poor. Finally, we apply the proposed decomposition to Spain in 2020 as regards certain individual and household characteristics, so as to identify the individuals most likely to suffer from energy poverty in the first year of the Covid-19 pandemic. • An decomposable index to measure energy poverty. • Poverty Decomposition in Incidence, Intensity and Inequality. • Sources of energy poverty increase in Spain on 2020. [ABSTRACT FROM AUTHOR]

'Energy efficiency first' is one of the key principles of the Energy Union, mainly due to it being the most cost effective way to reduce emissions, improving energy security, enhancing competitiveness and making energy consumption more affordable for all consumers. In light of the revised EU Energy Efficiency Directive, this paper discusses new developments brought by the EU together with the national case studies of Slovenia and Spain. Given that the paper has a specific focus on the industrial sector, it discusses the selected measures of the Energy Efficiency Directive, such as defined in Articles 7, 8, and 14, which are the most relevant to this sector. The paper also explores the newly issued integrated national energy and climate plans together with national measures and policies that support energy efficiency in industry, including the quantification of achieved and forecast energy savings in these two EU Member States. • The revised EU Energy Efficiency Directive is the key driver of change in Member States. • More ambitious energy efficiency targets are projected in Slovenia and Spain for 2030. • The integrated National Energy and Climate plans inspired further national developments. • Both countries committed to continue their national measures/schemes on energy efficiency. [ABSTRACT FROM AUTHOR]

With the economic growth of recent centuries, energy has become a structural good of prime necessity (Sovacool, 2011). The prevailing productive and economic model has made energy vulnerability, inequality and poverty a palpable reality in Spain. One of the instruments used to address this situation by the Government has been the implementation of the Bono Social de Electricidad (BSE) in 2009 based on a discount on the electricity tariff borne by families, a priori , with fewer resources. In 2017, the eligibility criteria were revised in such a way that the concept of vulnerable household was redefined. In this paper, through quasi-experimental methods and using the 2008–2011 and 2016–2019 longitudinal sample of the Living Conditions Survey, the effectiveness of this subsidy in reducing fuel poverty is evaluated. The results show that the BSE has not helped to mitigate it, identifying "new typologies of households" energetically poor. • Energy has become a structural good of prime necessity. • There is an increase in the energy vulnerability of households in Spain. • We identify poor households with novel subjective and objective indicators. • We found that BSE has not helped to mitigate fuel poverty. • Fuel poverty is a specific phenomenon that is included within the general poverty. [ABSTRACT FROM AUTHOR]

The Spanish power generation sector is facing dire problems: generation overcapacity, various tariff hikes over recent years, uncertainty over the financial viability of many power plants and a regulatory framework that lacks stability. This situation is the consequence of both poor energy policies and the economic crisis in the late 2000s and early 2010s. In this paper we analyze the following three points from an energy planning perspective: how the country has arrived at this situation; whether other alternatives would have been possible through adequate planning; and the quantitative benefits that would have been accrued from such planning. We do so by developing a LEAP model, and building three scenarios that allow to segregate the costs of the economic crisis from the costs of the lack of planning. We find that appropriate energy planning could have reduced investments in the Spanish power sector by 2010€28.6 billion without compromising on performance in terms of sustainability or energy security, while improving affordability. The main causes of these surplus investments were two supply bubbles: those of gas combined cycles and of solar technologies. The results of this work highlight the value of rigorous, quantitative energy planning, and the high costs of not doing it. [ABSTRACT FROM AUTHOR]

Proper planning for the dimensions of an electricity production and transmission system requires the availability of medium- and long-term electricity demand projections that are sufficiently reliable. Generally, these projections are directly linked to the estimated growth for the whole real GDP (gross domestic product), although an in-depth historical evolution of this demand, as that given in this article, advises the explicit consideration of several determinants. The aim of this paper is to present an alternative analysis of the demand for electricity based on a simple growth rate decomposition scheme that allows the key factors behind this evolution to be identified. It is possible, taking this scheme as a starting point, to develop a long-term forecasting model to obtain projections of electricity demand given the expected evolution of the key factors. The proposed methodology is illustrated using Spain as a case study to obtain demand projections till 2030. [ABSTRACT FROM AUTHOR]

This paper shows how exergy can be used to assess the mineral balance of a country and at the same time assess its mineral resource sustainability. The advantage of using such an approach is that the quality of the resources is taken into account, as opposed to the conventional procedure that uses tonnage as a yardstick. The exergoecology method evaluates mineral resources as the exergy required to replace them from a complete dispersed state to the conditions they were originally found with the best available technologies. The country chosen as a case study is Spain and serves as a representative example of the mineral situation in Europe. The general trend observed is that imports are increasing and domestic production is decreasing. The minerals with higher exergy replacement costs are mainly those imported, including fossil fuels and scarce minerals. In 2005, the domestic production of minerals was higher than the imports but since imports were mainly of scarce minerals, the exergy loss associated with such imports was higher compared to domestic production. As it happens to most European nations, Spain is a very dependent country regarding the supply of fossil fuels but not as much in the case of non-fuel minerals. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to optimize the size (electric power) of a cogeneration plant based on a biomass-fired Organic Rankine Cycle and connected to an existing district heating network, maximizing profitability. First, a model to determine the hourly thermal energy demand profile of a location in Spain has been derived, from open access meteorological data included in Spanish building regulations. Partial load model of an organic Rankine plant has also been obtained to increase the operation hours. These tools have been applied to two locations in Spain with different climatic severities, calculating the optimal size of the plant. The business model does not include subsidies. Calculations show that for population between 10,000 and 20,000 inhabitants the size of the plant ranges from 2 to 9 MWe and the internal rate of return ranges from 6% to 18%. The coverage of the thermal energy demand ranges from 40% to 80%. Regarding the trigeneration mode, it is concluded that cooling is only worth in locations with high summer severity and in full load operation mode, being the optimal size of the plant smaller in trigeneration mode than in cogeneration. [ABSTRACT FROM AUTHOR]

Photovoltaics (PV) has reached high level of maturity in terms of material efficiency and low production costs. For this reason, nowadays, lot of emphasis is put on the reduction of the operation and maintenance costs. Soiling is one of the issues that most affect these costs. So, the understanding of its electrical and economic implications is essential to optimize the cleaning routines and minimize the associated costs. This paper investigates the possibility of estimating soiling directly from PV performance data, without the need of installing specific soiling monitoring equipment, which typically needs careful and regular maintenance. Five analytical methods are evaluated and applied to the data of PV modules of different technologies (m-Si, CdTe and CIS). An experimental campaign is conducted in a location in Southern Spain with low-moderate levels of soiling. The methods show promising accuracies when used to obtain the soiling losses of a module, especially during soiling-intense and long dry periods. • Soiling losses were directly extracted from the performance data of PV modules. • The goodness of five different analytical methods was assessed. • These methods allow soiling to be quantified without need for additional sensors. • Each methodology was applied to PV modules of three different technologies. • The accuracies of the methods were higher in periods with greater soiling losses. [ABSTRACT FROM AUTHOR]

Photovoltaics (PV) has reached high level of maturity in terms of material efficiency and low production costs. For this reason, nowadays, lot of emphasis is put on the reduction of the operation and maintenance costs. Soiling is one of the issues that most affect these costs. So, the understanding of its electrical and economic implications is essential to optimize the cleaning routines and minimize the associated costs. This paper investigates the possibility of estimating soiling directly from PV performance data, without the need of installing specific soiling monitoring equipment, which typically needs careful and regular maintenance. Five analytical methods are evaluated and applied to the data of PV modules of different technologies (m-Si, CdTe and CIS). An experimental campaign is conducted in a location in Southern Spain with low-moderate levels of soiling. The methods show promising accuracies when used to obtain the soiling losses of a module, especially during soiling-intense and long dry periods. • Soiling losses were directly extracted from the performance data of PV modules. • The goodness of five different analytical methods was assessed. • These methods allow soiling to be quantified without need for additional sensors. • Each methodology was applied to PV modules of three different technologies. • The accuracies of the methods were higher in periods with greater soiling losses. [ABSTRACT FROM AUTHOR]

Net metering and net billing are electricity policies that enable grid-connected customer-generators (homes or businesses that own a PV (photovoltaic) or other generation technology connected to the grid) to offset some or all their electricity consumption and get paid for excess energy injected into the grid. There are many policies of net metering and net billing used by different countries. In this paper we propose a modified definition of some of the modalities that can be applicable to the two drafts of the royal decree for the Spanish regulation. Also we show, for the first time, the mathematical formulation of a comprehensive methodology for the assessment of the different modalities of net metering and net billing used in different countries. We compare several cases, taking into account the actual two Spanish drafts, the two models proposed by the Spanish National Energy Commission in its reports about the drafts and other modalities used in other countries, concluding that the first Spanish draft would have been a superior regulation for PV net metering; however, the second draft impedes the profitability of the PV so no user will install a grid-connected PV system if this second draft is finally approved. [ABSTRACT FROM AUTHOR]

In the last years the electricity industry has faced a restructuring process. Among the aims of this process was the increase in competition, especially in the generation activity where firms would have an incentive to become more efficient. However, the competitive behavior of generating firms might jeopardize the expected benefits of the electricity industry liberalization. The present paper proposes a conjectural variations model to study the competitive behavior of generating firms acting in liberalized electricity markets. The model computes a parameter that represents the degree of competition of each generating firm in each trading period. In this regard, the proposed model provides a powerful methodology for regulatory and competition authorities to monitor the competitive behavior of generating firms. As an application of the model, a study of the day-ahead Iberian electricity market (MIBEL) was conducted to analyze the impact of the integration of the Portuguese and Spanish electricity markets on the behavior of generating firms taking into account the hourly results of the months of June and July of 2007. The advantages of the proposed methodology over other methodologies used to address market power, namely Residual Supply index and Lerner index are highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Spanish local governments may offer, in accordance with Royal Decree 2/2004, tax credits up to 50% in Real Estate Tax for those with installed solar powered thermal or electrical energy systems. This paper analyzes by logistic regression estimation which factors influence the decision of governments to implement this tax credit. Factors included as explanatory variables are related to the characteristics of municipalities, fiscal stress, environmental stress, the environmentally friendly nature of municipalities, the neighboring effect, and economic motivations. Results show that municipalities applying these measures are mostly large in size, with high solar potential, with predominantly collective-housing buildings, with low fiscal stress, mainly rural, environmentally friendly, surrounded by municipalities implementing similar measures and with higher unemployment rates. [Copyright &y& Elsevier]

Abstract: This paper analyses the water-energy nexus in irrigation districts (IDs) under the semi-arid conditions of south-eastern Spain. Three IDs supplied by different water sources and subjected to water scarcity over time were studied throughout a 10-year period (2002–2011). A set of performance indicators was selected to characterise water and energy relationships at three management levels: basin, irrigation district, and farm. Basin level was the largest energy consumer, representing 71–82% of the annual total consumption, which ranged from 0.95 to 1.55 kWh m−3. Basin energy consumption increased depending on the water source as follows: surface water, recycled water, groundwater, external water transfer, and desalinated brackish water. ID level involved 12–15% of the annual total consumption. The highest values were attained in periods of water scarcity, when the available sources were those with higher energy requirements. ID modernisation resulted in slight decreases in energy consumption at that level. At farm level, energy consumption was lacking when farmers took advantage of the pressure head in the ID distribution network, whereas it was from 0 to 0.19 kWh m−3 when the available pressure head was lost. Finally, water and energy productivities by the main crops were analysed. [Copyright &y& Elsevier]

Abstract: The peculiarities of High Concentrator Photovoltaic (HCPV) modules make it very difficult to estimate their output. There are some methods to estimate the maximum power of an HCPV module which provide good results, but they are not easy to apply for the following reasons: a) they do not offer a comprehensive explanation of the entire procedure, b) they need some intrinsic parameters of MJ (multi-junction) solar cells which are difficult to obtain, c) it is necessary to have either complex and expensive devices for indoor measurements, and/or an accurate and complete set of outdoor measurements. This paper is intended to propose a model based on Artificial Neural Networks (ANNs) to predict the maximum power of an HCPV module using easily measurable atmospheric parameters. To this end, a group of atmospheric parameters together with the maximum power of an HCPV module have been measured throughout a whole year at a research centre located in the south of Spain. The results showed that using atmospheric parameters, the proposed ANN is capable of estimating the maximum power of an HCPV module with a mean square root error of 3.29%. This model could be extended to other modules and other places. [Copyright &y& Elsevier]

Cool roofs are an inexpensive method to save energy and to improve the comfort level in buildings in mild and hot climates. A high scale implementation of cool roofs in Andalusia, in the south of Spain, could potentially save 295,000 kWh per year, considering only residential buildings with flat roofs using electrical heating. At the current energy prices, consumers can save 59 million euros annually in electricity costs and the emission of 136,000 metric tons of CO2 can be directly avoided every year from the production of that electricity. If radiative forcings are considered, Andalucía can potentially offset between 9.44 and 12 Mt of CO2. All the provinces in the rest of Spain are also studied in this paper. The biggest savings are achieved in Gran Canaria (48%), Tenerife (48%), Cádiz (36%), Murcia (33%), Huelva (30%), Málaga (29%), Almería (29%) and Sevilla (28%), where savings are greater than 2 euros per square meter of flat roof for old buildings with dark roofs. For the biggest cities the range of savings obtained are: between 7.4% and 11% in Madrid, between 12% and 18% in Barcelona and between 14% and 20% in Valencia. [Copyright &y& Elsevier]

Abstract: This paper focuses on the validation of a dynamic simulation model used to describe the performance of an existing solar cooling installation located in Zaragoza (Spain). The dynamic model has been developed under the simulation environment TRNSYS. The aim of this simulation model is to dispose of a tool in order to use it to evaluate different energy improvement actions in a real solar cooling installation. This solar cooling installation has been monitored and analyzed since 2007. The COP of this experimental solar cooling system presents a great influence from its heat rejection sink, a dry cooling tower. Once the model was validated with the experimental data obtained from the real installation, it was used to predict the chiller performance with a new geothermal sink, which started to operate in 2009. The present work describes the design and validation model process, as well as the comparison between the model results and the monitoring ones with the geothermal heat rejection system. [Copyright &y& Elsevier]

Abstract: The European Union has established challenging targets for the share of renewable energies to be achieved by 2020; for Spain, 20% of the final energy consumption must be from renewable sources at such time. The aim of this paper is the analysis of the consequences for the electricity sector (in terms of excess cost of electricity, investment requirements, land occupation, CO2 emissions and overcapacity of conventional power) of several possibilities to comply with the desired targets. Scenarios are created from different hypotheses for energy demand, biofuel share in final energy in transport, contribution of renewables for heating and cooling, renewable electricity generation (generation mix, deployment rate, learning curves, land availability) and conventional power generation (lifetime of current installations, committed deployment, fossil fuel costs and CO2 emissions cost). A key input in the estimations presented is the technical potential and the cost of electricity from renewable sources, which have been estimated in previous, detailed studies by the present authors using a methodology based on a GIS (Geographical Information System) and high resolution meteorological data. Depending on the scenario, the attainment of the targets will lead to an increase in the cost of electricity from 19% to 37% with respect to 2007. [Copyright &y& Elsevier]

Abstract: This study analyses three feasible regulation methods of an in-service cogeneration plant. The main task is to study the potential energy savings, CO2 reduction and the increase in profitability compatible with the lowest transformation costs. The cogeneration system is composed of two General Electric LM2500 gas turbines and a heat recovery steam generator (HRSG). Two plant localizations in Spain have been considered; San Fernando (Cádiz) where the current plant is located, and Burgos. The latter has been taken into account to analyze the effect of cooler weather on the regulation methods. The paper has been divided into three parts. First, a revision of the current legislation regarding cogeneration in Spain is shown. Second, a description of the power plant and the proposed regulation methods are set out. Then, the cogeneration plant is modelled with the objective of evaluating the effects of the regulation methods in power, generated steam and thermal oil flow. Finally, the model was applied to analyze the profit obtained from different regulation combinations and to compare the benefits of those regulation methods in the two locations with different climatic situations. The main conclusion reached is the importance to meet the requirements of Spanish legislation in order to obtain advantages in the sale of electricity; an increased profit of up to 60% was obtained in the simulation. In addition, it is evident that the regulation is more important when ambient temperature is lower. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to develop a methodology based on the input–output approach which allows us to identify the structural and technological responsibility of manufacturing sectors in electricity consumption. Sectors with a high structural responsibility are those whose products are strongly demanded by other sectors and this leads to a high electricity consumption/production. Sectors with a high technological responsibility are those whose technologies use inputs which directly or indirectly require much electricity independently of the composition of final demand in the economy. This methodology is applied to the manufacturing sectors in Spain. It is found out that the chemical sector and industries manufacturing metal products have a large structural responsibility, but their technological responsibility is low. In contrast, the mineral (non-metallic) sectors form a cluster of industries with a high technological responsibility. [ABSTRACT FROM AUTHOR]

Abstract: In transmission and distribution systems, the high number of installed transformers, a loss source in networks, suggests a good potential for energy savings. This paper presents how the Spanish Distribution regulation policy, Royal Decree 222/2008, affects the overall energy efficiency in distribution transformers. The objective of a utility is the maximization of the benefit, and in case of failures, to install a chosen transformer in order to maximize the profit. Here, a novel method to optimize energy efficiency, considering the constraints set by the Spanish Distribution regulation policy, is presented; its aim is to achieve the objectives of the utility when installing new transformers. The overall energy efficiency increase is a clear result that can help in meeting the requirements of European environmental plans, such as the ‘20–20–20’ action plan. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper is to identify those sectors that contribute most to electricity consumption in Spain, using a methodology based on input–output tables, and to derive some recommendations aimed at increasing energy efficiency in those sectors. This input–output approach is complemented with a sector-focused study in which the availability of electricity-efficient technologies per sector and the barriers to their uptake are identified. This hybrid approach is deemed useful to derive policy implications. We thus propose several instruments to remove those barriers. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The water cycle is governed by the thermodynamic laws. Therefore Thermodynamics and more specifically Exergoecology, that is the application of the exergy analysis in the evaluation of natural fluxes and resources on Earth, could help to build a solid cost structure based strictly on Physics and far away from price policies or subjectivities. Any type of degradation of water bodies along their rivers, lakes, etc., could then be quantified. Moreover, the physical information of the resource can be unified into universal units (energy units), and the monetary conversion of exergy costs is automatic through conventional energy prices. This paper presents a new discipline named “Physical Hydronomics”, as a guide to assess environmental costs included in the European Water Framework Directive (WFD). [Copyright &y& Elsevier]

Abstract: In this paper, different electricity demand scenarios for Spain are presented. Population, income per capita, energy intensity and the contribution of electricity to the total energy demand have been taken into account in the calculations. Technological role of different generation technologies, i.e. coal, nuclear, renewable, combined cycle (CC), combined heat and power (CHP) and carbon capture and storage (CCS), are examined in the form of scenarios up to 2050. Nine future scenarios corresponding to three electrical demands and three options for new capacity: minimum cost of electricity, minimum CO2 emissions and a criterion with a compromise between CO2 and cost (CO2-cost criterion) have been proposed. Calculations show reduction in CO2 emissions from 2020 to 2030, reaching a maximum CO2 emission reduction of 90% in 2050 in an efficiency scenario with CCS and renewables. The contribution of CCS from 2030 is important with percentage values of electricity production around 22–28% in 2050. The cost of electricity (COE) increases up to 25% in 2030, and then this value remains approximately constant or decreases slightly. [Copyright &y& Elsevier]

Using blends of vegetable oils with petroleum derivatives for heating purposes has several advantages over other energy applications for vegetable oils. These advantages are presented in this paper, using the results obtained from the installation of conventional heat generation using diesel and sunflower oil mixtures and the possibilities this holds for Castilla y León. Castilla y León is the biggest region of Spain; its main activity is the agriculture, with a continental climate. [Copyright &y& Elsevier]

This paper proposes a capacity investment model to analyze the influence of the controllability of the charge of plug-in electric vehicles (PEVs) in generation and storage expansion decisions. The proposed model provides the financial incentives that should be offered to PEV users in order to implement the optimal expansion decisions. Considering that the decision-making process faced by the power system planner must simultaneously consider long- and short-term uncertainties, a three-stage stochastic programming problem is formulated. In this model, capacity investments and financial incentives for PEV users are decided in the first stage, whereas operating decisions regarding the day-ahead and real-time markets are made in the second and third stages, respectively. Numerical results are provided from a realistic case study based on the isolated power system comprising Lanzarote and Fuerteventura islands in Spain. • Capacity expansion on generating and storage units. • Electric vehicles can be controlled by the power system operator. • Long- and short-term uncertainties are explicitly considered. • Incentives offered to electric vehicle users are determined. • The number of controlled vehicles depends on the offered incentives. [ABSTRACT FROM AUTHOR]