L. Narvarte

Universidad Politécnica de Madrid | UPM · Instituto de Energía Solar (IES)

With the emergence of energy communities, this paper explores their operationalization as a tool with which to create large and stable citizen science and education hubs focused on energy, where citizens can have the chance of exploring a first-hand approach to the energy transition. We present the rationale behind an energy community, whose purpos...

This paper proposes a new automatic tuning method for the proportional-integral (PI) controllers of photovoltaic irrigation systems (PVIS) without the need for any other power source or batteries. It enables the optimisation of the values of the PI parameters (Kp and Ki) automatically, eliminating the requirement for skilled personnel during the in...

Universities as centers for innovation by nature, can play a relevant role in serving as education hubs for citizens in energy, promoting individual and collective behavioral changes among community members. By collaborating with their own communities on the energy transition, universities can become more sustainable while providing firsthand exper...

High-power diesel-based or grid-connected irrigation systems are being replaced by battery-free, high-power stand-alone Photovoltaic Irrigation Systems (PVIS) that reduce energy costs by up to 80% and for which no experimental performance data are available. The operation of PVIS is affected by various factors, some unrelated to the quality of the...

This paper presents an economic assessment of three drying systems (DS) with different configurations: diesel-powered (DDS), grid-powered (GDS), and photovoltaic-powered (PVDS). The third configuration, PVDS, presents important technological innovations regarding the electric configuration (stand-alone PV, without batteries or grid support) and the...

One of the greatest challenges in stand-alone photovoltaic irrigation systems (PVIS) without batteries is the tuning of PID controllers and the evaluation of their performance once the system is tuned. Tuning method must be applied in clear days (constant irradiance) while performance must be evaluated in the most unfavourable circumstances, which...

The growing market of large-power photovoltaic irrigation systems (PVISs)—made of systems with different and several motor pumps working in parallel—needs simulation tools capable to estimate their energy and water productivity. The objective of this paper is to present the simulation models developed for parallel multipump PVISs fed by a single PV...

Stand-alone large-power PV irrigation systems without batteries is a recent innovation. This means that their design has not yet reached maturity and there are no experimental data about their performance available. This paper is a contribution, on the one hand, to the systematic tuning of the control of this type of systems and, on the other hand,...

In order to mitigate PV power fluctuations, ramp rate control is performed coupling battery energy storage systems to PV plants. In previous works, we developed a method to minimise the power and energy capacity of a battery by considering the probability of occurrence of fluctuations and a penalty imposed in the event of not complying with a certa...

One of the UN Sustainable Development Goals is the supply of sustainable energy even where no electrical grid is available. The photovoltaic rural electrification programs are the most common systems implemented in remote areas, especially in developing countries. These programs include the systems installation and their maintenance for a given per...

This article explains the methodology used in a hybrid photovoltaic-grid irrigation system simulation tool, as well its application to a direct pumping system in Marrakech, Morocco. It is an intensive olive tree cultivation, with a daily irrigation need of 8 hours between March and October. The photovoltaic energy used in this period is 1456 kWh/kW...

The use of photovoltaic (PV) systems for powering heat pumps (HP) leads to an economic, energy efficient and environmentally friendly alternative for heating and cooling generation. A technical solution developed by the authors permits stand-alone configurations to operate without batteries, mitigating up to 75% of the solar power fluctuations resu...

The coupling of Photovoltaic (PV) and Heat Pump (HP) systems is an attractive alternative for reducing the energy consumption associated to cooling applications, as well as increasing the renewable share in the electric systems. This work presents the results of the technical validation of a stand-alone PV-HP system operating without batteries, for...

Open questions remain regarding the use of bifacial photovoltaic (PV) modules, such as how to link the energy-yield modelling of large bifacial PV plants with further on-site measurements campaigns, the effect of the non-uniformity of the rear irradiance, as well as the convenience of varying the geometry of the plants to enhance the bifacial contr...

The fault detection applied to a large amount of small distributed PV systems needs to be simple, cost-effective, and reliable. This work presents a fault detection procedure applied to distributed PV system fleets, based on a novel performance indicator, designated as Performance to Peers (P2P), that can be constructed on the sole basis of the com...

The objective of this study was to assess whether precision photovoltaic irrigation represents a sustainable alternative to traditional systems, where the energy and environmental performances were firstly evaluated through energy and carbon payback times (EPBT and CPBT). The study involved five Photovoltaic Irrigation Systems (PVIS), ranging from...

In this work, a systematic study of different tuning rules of proportional-integral (PI) control parameters applied to Photovoltaic Irrigation Systems (PVIS) based on Standard Frequency Converters (SFCs) has been carried out. A laboratory system has been implemented to obtain the PI control parameters by means of the most widely accepted tuning rul...

In the last few decades, the demand for reversible heating and cooling systems has increased significantly, together with the need to generate energy in a more efficient and sustainable way. Consequently, the concept of solar photovoltaic (PV) powered heat pumps (HP) has become very attractive in order to match the heating/cooling demand with a ren...

The electricity costs for agricultural applications is dramatically increasing in the last years, making the solutions based on photovoltaics more attractive once the technological barriers that impeded high-power PV irrigation systems (PVIS) have been removed. But the data available in the literature are restricted to small-power PVIS what limits...

Large-power PV irrigation systems (PVIS) from 40 kWp to 1 MWp are increasingly being introduced onto the market since the main technical barriers have been removed and some real-scale demonstrators have shown cost savings up to 80% when compared with the electricity costs from the grid or diesel generators. The electricity compatibility between the...

The current state of the art of photovoltaic (PV) irrigation systems is limited to PV peak powers below 40 kWp, which does not cover the irrigation needs of farmers, co-operatives, irrigator communities, and agro-industries. This limitation of power is due to two main technical barriers: The quick intermittence of PV power due to the passing of clo...

This paper presents a new method for selecting a pump for large-power PV irrigation systems working at a variable frequency. This can have a significant impact since the traditional way of selecting the pump is based on maximizing the efficiency of pump in the duty point at a certain single operating frequency, which is not useful for PV irrigation...

The adaptation of the mature PV water-pumping technology to large power irrigation applications requires the problems associated to PV power intermittencies and matching PV production with the irrigation needs to be resolved. This paper presents the innovations developed, implemented and tested in a PV irrigation prototype installed in a real well...

Over the last decades, traditional olive production has been converted to intensive and super-intensive cultivation systems, characterized by high plant density and irrigation. Although this conversion improves product quality and quantity, it requires a larger amount of energy input. The new contributions in this paper are, first, an analysis of t...

This paper presents a new type of PV structure called delta, ΔS(60). This was developed in order to achieve a constant irradiance daily profile similar to that obtained with a North-South horizontal axis tracker (1xh) since this constancy is essential for a number of PV applications, namely for PV irrigation systems. A comparison between these two...

A life cycle assessment (LCA) methodology was used to evaluate the cumulative energy demand and the related environmental impact of three large-power stand-alone photovoltaic (PV) irrigation systems ranging from 40 kWp to 360 kWp. The novelty of this analysis is the large power of these systems as the literature up to now is restricted to modeled P...

The setting up of innovative irrigation water management might contribute to the mitigation of negative issues related to climate change. Our hypothesis was that globe artichoke irrigated with a traditionally drip system could be converted to an innovative water management system based on precision irrigation techniques and on evaporative cooling a...

This paper presents an economic assessment of large power (from tens to hundreds kWp) PV irrigation systems in the ECOWAS region, evaluating the economic feasibility of substituting diesel-powered and grid-powered systems with PV ones. Seven countries from the ECOWAS region were considered and two irrigation operating modes were compared (pumping t...

The impact of long range Saharan dust transport, arising from one event in February and other in March 2017, on the performance of photovoltaic flat panels is reported as a case study of soiling. Through satellite images, dust coming from north Africa was detected, while using the Hybrid Single-Particle Lagrangian Integrated Trajectory, specific or...

This article presents an analysis on irradiance modelling and its impact on energy estimation uncertainty. In particular, the calculation of the effective in-plane irradiance from broadband horizontal irradiance is assessed. Thirty-one models for irradiance distribution, decomposition, transposition and spectral correction have been considered. The...

This paper describes a 360 kWp PV water pumping system to an elevated water pool in a borehole named San Cristóbal of the Irrigator’s Community of Alto Vinalopó, Villena, Spain. This system is able to work along the year, being the maximum need to satisfy in July. The goal of this paper is to show the design, the implementation of the system and so...

This paper describes a 140 kWp hybrid PV-diesel pumping demonstrator for constant pressure irrigation in a 200 ha olive tree plantation at Herdade de São Bernabé, Alter do Chão, Portugal. The PV system was installed in June 2016 and has been working since then. A previous system fed exclusively by a diesel generator was already implemented, and the...

This paper describes a 120 kWp hybrid PV-grid irrigation system at constant pressure, which has been installed in a 233 ha farm devoted to the intensive cultivation of olive trees in Tamelelt, Morocco. The description includes important information regarding system configuration, working control and implementation. In addition, monitoring data betw...

This paper describes a 160 kWp PV irrigation system at constant pressure installed in Valladolid, Spain. The objective of this paper is to present the design, as well as the implementation of the system. Moreover, monitoring data, from 22nd June to 31st August 2017, is analyzed and some first results are presented. During this period, the system wa...

PV power fluctuations caused by clouds are leading operators of grids with high renewable energy penetration rates to impose ramp rate limitations. Costly battery energy storage systems are used for fulfilling these regulations but the question of the power and energy requirements for accomplishing them has not been fully answered. This work analys...

In decentralised rural electrification through solar home systems, private companies and promoting institutions are faced with the problem of deploying maintenance structures to operate and guarantee the service of the solar systems for long periods (ten years or more). The problems linked to decentralisation, such as the dispersion of dwellings, d...

The invention can be included in the technical field of the methods for calculating the power generated by electrical centres based on intermittent power sources, wherein said method accurately reproduces the dynamic in the power generated by a set of dispersed photovoltaic systems in all the relevant parameters for the operator of the electrical s...

This paper presents the results of the implementation of a self-consumption maximization strategy tested in a real-scale Vanadium Redox Flow Battery (VRFB) (5 kW, 60 kWh) and Building Integrated Photovoltaics (BIPV) demonstrator (6.74 kWp). The tested energy management strategy aims to maximize the consumption of energy generated by a BIPV system t...

Método de detección automática y diagnóstico de fallos de operaciones en instalaciones solaresfotovoltaicas distribuidas. El método solo requiere la medida de los datos de producción de energía, de manera que el material necesario por parte del operador de la instalación fotovoltaica se basa en un equipo capaz de medir la energía producida por las...

The number of solar photovoltaic (PV) systems installed in Europe has drastically increased over the last few years, mostly thanks to the advantageous feed-in tariffs set in by each country’s government. A relatively little fraction of the energy production data of these PV systems has been analysed, and as a consequence, there still remain wide...

The data were collected at more than 31,000 PV systems in Europe. Most of them are located in the UK, Belgium and France. Spain has few PV systems, but they are important ones because most of them are large PV plants, which sum up a larger total peak power than the rooftop installations from any other country. About 300 PV systems are located in ot...

Large-scale PV fields are a complicated target for monitoring and performance evaluation. In this paper, field experience with multirotor UAV has been reported. A X-frame quadcopter equipped with various VIS and IR cameras is used to detect defects responsible for performance degradation. Usually in laboratory environment, hires VIS photos, EL phot...

The Performance ratio (PR) describes the technical quality of PV installation. On yearly basis, it is a good performance indicator for monitoring and comparisons of PV plants at different locations, but for shorter testing periods or commissioning, weekly-based or hourly-based indicators are preferable. We have developed a testing tool based on sma...

Li-ion batteries are modern electrical energy storage systems which are undergoing an intense development in their technological features. Their high specific energy, efficiency and durability, together with the lowering of their production costs, are placing them as one of the most promising actors in the field of electrical energy storage technol...

We have tried to cast some light on some of the numerous questions concerning the performance of solar PV systems in Europe. We have based our analysis on the operational data monitored at more than 31,000 PV systems in Europe. These installations comprise residential and commercial rooftop PV systems distributed over 9 different countries, includi...

This paper describes the modelling of components for large PV pumping systems, which have been implemented in an online and free-software simulator of PV systems called SISIFO, which is publicly available at www.sisifo.info. Among other features, this software tool allows the prediction of water pumped as function of PV size and type and the analys...

This paper presents a description of an open-source simulation tool (features, models and calculation procedures) that has been developed under the support of the European project called PVCROPS. The main advantage of this tool is that it uses as input just parameters guaranteed by the manufacturers of the different components of a PV plant. This w...

In this paper, a comparison between two approaches to predict the AC power output of PV systems is carried out in terms of forecast performance. Each approach uses one of the two main types of PV modeling, parametric and nonparametric, and both use as inputs several forecasts of meteorological variables from a Numerical Weather Prediction model. Fu...

The hot-spot phenomenon is a relatively frequent problem occurring in current photovoltaic generators. It entails both a risk for the photovoltaic module’s lifetime and a decrease in its operational efficiency. Nevertheless, there is still a lack of widely accepted procedures for dealing with them in practice. This paper presents the IES–UPM observ...

Método de generación de datos de irradiación solar a partir de datos de producción energética de instalaciones solares fotovoltaicas. El método solo requiere la medida de los datos de producción de energía, de manera que el material necesario por parte del operador de la instalación fotovoltaica se basa en un equipo capaz de medir la energía produc...

Forecasting the AC power output of a PV plant accurately is important both for plant owners and electric system operators. Two main categories of PV modeling are available: the parametric and the nonparametric. In this paper, a methodology using a nonparametric PV model is proposed, using as inputs several forecasts of meteorological variables from...

O método descrito neste artigo detecta problemas operacionais nos sistemas fotovoltaicos integrados aos edifícios (BIPV) baseado apenas nos dados de produção de energia, não exigindo o conhecimento das condições de operação. O procedimento, aplicado em diversos sistemas BIPV na Europa, identifica as variações anormais de um indicador de desempenho...

BIPV systems are small PV generation units spread out over the territory, and whose characteristics are very diverse. This makes difficult a cost-effective procedure for monitoring, fault detection, performance analyses, operation and maintenance. As a result, many problems affecting BIPV systems go undetected. In order to carry out effective autom...

Assuring the sustainability of quality in photovoltaic rural electrification programmes involves enhancing the reliability of the components of solar home systems as well as the characterization of the overall programme cost structure. Batteries and photovoltaic modules have a great impact on both the reliability and the cost assessment, the batter...

El objetivo principal de este trabajo es implementar una herramienta de análisis automático de datos de operación para detectar fallos en instalaciones fotovoltaicas domésticas que disponen de sistemas de monitorización. Para ello se han analizado los datos de productividad de 10.650 sistemas fotovoltaicos (9.657 situados en Francia y 993 en Bélgic...

Actual system performance of a PV system can differ from its expected behaviour.. This is the main reason why the performance of PV systems should be monitored, analyzed and, if needed, improved on. Some of the current testing procedures relating to the electrical behaviour of PV systems are appropriated for detecting electrical performance losses,...

BIPV systems are small PV generation units spread out over the territory, and whose characteristics are very diverse. This makes difficult a cost-effective procedure for monitoring, fault detection, performance analyses, operation and maintenance. As a result, many problems affecting BIPV systems go undetected. In order to carry out effective autom...

Effective diagnosis of BIPV failure is critically important for reducing their operational costs and achieving greater revenue returns for BIPV owners. The PVCROPS team have successfully demonstrated that a novel data analysis method to diagnose BIPV performance failures can yield significantly more accurate results than existing satellite data bas...

The engineering of solar power applications, such as photovoltaic energy (PV) or thermal solar energy requires the knowledge of the solar resource available for the solar energy system. This solar resource is generally obtained from datasets, and is either measured by ground-stations, through the use of pyranometers, or by satellites. The solar irr...

The engineering of solar power applications, such as photovoltaic energy (PV) or thermal solar energy requires the knowledge of the solar resource available for the solar energy system. This solar resource is generally obtained from datasets, and is either measured by ground-stations, through the use of pyranometers, or by satellites. The solar rad...

This work presents a method that allows for automatically analyzing the performance and detecting the failures of a BIPV system at different temporal resolutions, in particular at monthly, daily and hourly levels. We have developed a procedure that is capable of detecting operational problems on the sole basis of the energy production data measured...