Chris Gueymard

Solar Consulting Services · Research

The spectral distribution of the solar irradiance incident on photovoltaic (PV) modules is a key variable controlling their power production. It is required to properly simulate the production and performance of PV plants based on technologies with different spectral characteristics. Spectroradiometers can only sense the solar spectrum within a wav...

The Advanced Himawari Imager (AHI) onboard the Himawari-8 spacecraft from the Japan Meteorological Agency (JMA) enables retrieval of aerosol optical depth (AOD) with high spatio-temporal resolution. This work demonstrates that the latest version of Level-3 AHI AOD product is affected by an overall underestimation against ground measurements from 98...

In this work, the performance of clear-sky direct normal irradiance (DNI) and global horizontal irradiance (GHI) predictions generated with three state-of-the-art solar radiation models with different degrees of complexity is assessed by comparison with high-quality measured irradiance data at E ́vora, Portugal. The libRadtran, SMARTS, and REST2 ra...

Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis. The satellite products are tested in terms of their ability to estimate photovoltaic (PV) spectral effects for six PV module technologies. Spectra are also compared directly. CM-SAF SRI generally outperforms First Solar and "no spectral effects" benchmarks, except...

A novel automatic filtering methodology is proposed for 1-min GHI and DIF data using surface measurements obtained at five sites located in various climate zones of Argentina. The methodology contemplates DIF information obtained through the use of a shading ring instead of the shading ball that requires a solar tracker. Three different flags are p...

Bifacial PV technology is now becoming a key component of the solar energy industry. Several studies have investigated the quantification of bifacial gains as a function of surface albedo. Because of the latter's high spatiotemporal variability and lack of appropriate global data at high resolution, there is now a strong demand for the precise char...

Backside irradiance comes from different directions. Structures have a 3D effect blocking the reflected irradiance. Conditions change from one point to another over the PV generator. Different mounting solutions are available. In the case of trackers, the conditions change over time because of sun movement due to tracker movement.

•Analysis of the bifacial gain installed on highly reflective rooftops •3D evaluation of the rear irradiance to consider non homogenous distribution •Identification of the key parameters (modules elevation, row distance) that have an influence in the bifacial energy gain •Cell level irradiance distribution and breakdown per component (diffuse and d...

Provides examples of PV energy simulation with the Lusim GPU-based 3D tool, which facilitates the detailed modelling of complex geometries and scenarios for a variety of applications, including shading, bifacial gain, agrivoltaics, and PV greenhouses.

Fourth Edition of the Handbook: Planned Timeline • To help stakeholders stay aware of the latest research in solar resource data, the National Renewable Energy Laboratory (NREL), in collaboration with the International Energy Agency (IEA) Photovoltaic Power Systems Programme (PVPS) Task 16 and the Solar Power and Chemical Energy Systems (SolarPACES...

Bifacial PV technology is now becoming a key component of the solar energy industry. Several studies have investigated the quantification of bifacial gains as a function of surface albedo. Because of the latter’s high spatiotemporal variability and lack of appropriate global data at high resolution, there is now a strong demand for the precise char...

The distribution of diffuse radiance over the sky hemisphere is an important quantity that is required in many applications. Its spectral variation is useful when considering processes having a spectral dependence, such as photovoltaics (PV). Here, a clear-sky spectral radiance model is developed from radiative transfer theory, using appropriate pa...

Surface albedo has been constantly used in solar energy modeling. In recent times, the growing development of bifa-cial PV modules has ignited a surge of interest for this variable. However, there is a lack of knowledge in the energy industry about several key aspects concerning albedo. In this work, we present an evaluation of 8 different sources...

Bifacial PV technology has a rapidly growing presence in the solar industry. Although several studies have tried to quantify bifacial gains, there is limited information about the associated uncertainty-an essential quantity in solar PV projects. In this regard, a sensitivity analysis of the uncertainty in annual energy production of a bifacial PV...

Comparison of modeled surface irradiance estimates to ground measured irradiance data at 161 world stations.

A very recent gridded product for the hourly global horizontal irradiance (GHI), derived from the measurements of the Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) launched by a NOAA/NASA/USAF consortium, is validated at 31 locations worldwide, from January, 2017 to June, 2019. In contrast to those tr...

Solar resource assessments most generally require atmospheric information, which is customarily acquired from gridded datasets. The spatial scale mismatch problem, i.e., the difference in spatial representativeness of gridded data and in situ measurements, therefore becomes relevant. This study examines how the gridded data used as inputs to clear-...

Modelled irradiance data based on satellite products is frequently used in solar energy applications and atmospheric sciences. This kind of data is offered by many different institutional or commercial providers, and currently it is not possible for users to independently identify the best provider for their specific application and location. This...

The Satellite Application Facility on Climate Monitoring (CM-SAF) Spectral Resolved Irradiance (SRI) and National Renewable Energy Laboratory National Solar Radiation Database Spectral on Demand (NSRDB-S) satellite-based spectral irradiance products are tested here against benchmark data and models at seven ground stations: one in Spain for CM-SAF...

p>The Satellite Application Facility on Climate Monitoring (CM-SAF) Spectral Resolved Irradiance (SRI) and National Renewable Energy Laboratory National Solar Radiation Database Spectral on Demand (NSRDB-S) satellite-based spectral irradiance products are tested here against benchmark data and models at seven ground stations: one in Spain for CM-SA...

The ability to forecast solar irradiance plays an indispensable role in solar power forecasting, which constitutes an essential step in planning and operating power systems under high penetration of solar power generation. Since solar radiation is an atmospheric process, solar irradiance forecasting, and thus solar power forecasting, can benefit fr...

(NREL) is a world-leading solar calibration and measurement facility and maintains and disseminates the World Radiation Reference (essentially the W/m2) for the United States, which is essential for traceable and accurate measurements of solar radiation at all solar generation facilities. SRRL operates two International Organization for Standardiza...

Cloud parameters, as key inputs in radiative transfer algorithms, have a critical impact on surface shortwave radiation (SSR) computation. By introducing a parameterization of cloud transmittance and reflectance, based on radiative transfer simulations, this study improves the accuracy of an existing physically based model which severely underestim...

The Advanced Himawari Imager (AHI) onboard the Himawari-8 spacecraft from the Japan Meteorological Agency (JMA) enables retrieval of aerosol optical depth (AOD) with high spatio-temporal resolution. This work demonstrates that the latest version of Level-3 AHI AOD product is affected by an overall underestimation against ground measurements from 98...

This paper describes a new approach for hourly global solar radiation forecasting based on a hybrid artificial neural network technique combining a residual neural network (RESNET) for powerful feature extraction of the most relevant moments of the past, and a long short-term memory (LSTM) technique for efficient projection into the future. Based o...

Various technical aspects of the measurement and modeling of the solar energy potential are addressed in this chapter to provide a solid understanding of the different steps involved in the practice of solar resource assessments. The information presented here represents the state of the art with regard to the availability of solar resource databas...

EXTENDED ABSTRACT Solar energy is a vast and clean resource that can be harnessed with great benefit for humankind. It is still currently difficult, however, to convert it into electricity in an efficient and cost-effective way. One of the ways to produce energy is the use of various focusing technologies that concentrate the direct normal irradian...

EXTENDED ABSTRACT Solar radiation forecasting is an important technology that is necessary to increase the performance, management, and control of modern electrical grids. It allows energy regulators to estimate the near-future output power of solar power plants, and can help to reduce the effects of power fluctuations on the electricity grid, thus...

This is a short overview of solar radiation essentials and research needs for solar energy applications, within the framework of IEA PVPS Task 16.

The spectral distribution of the solar irradiance incident on photovoltaic (PV) modules is a key variable controlling their power production. It is required to properly simulate the production and performance of PV plants based on technologies having different spectral characteristics. Spectroradiometers allow solar spectra to be measured within a...

Ground-based radiation measurements are required for all large solar projects and for evaluating the accuracy of solar radiation models and datasets. Ground data almost always contain low-quality periods caused by instrumental issues, logging errors, or maintenance deficiencies. Therefore, quality control (QC) is needed to detect and eventually fla...

In the case of hybridization between a wind farm and an adjacent solar photovoltaic (PV) power plant, the wind farm can cast shadows on the nearby PV generators. The rotation of long blades in the nearby area of the modules induces dynamic disturbances during short periods of time that can have a significant impact on the PV generation, while being...

The installation of solar photovoltaic (PV) modules on carports or canopies combines power generation and shaded parking for vehicles in the case of carports, or power generation and shelter and shade for people, animals or goods without significant waste of land. Bifacial technology opens the door to various improvements and even new kinds of solu...

Agrivoltaics is a novel application of solar (PV) photovoltaic power generation where the PV modules are installed in the same field as to where the crops are also cultivated, combining land use. This study is focused on an installation with rows of vertical PV bifacial modules, blurring the classical separation between front and back side and requ...

Several simulation tools have appeared on the market to estimate the bifacial energy gain (BEG) of bifacial photovoltaic (PV) systems. These tools use two main families of methods that provide a quick estimation of the BEG or a detailed analysis of it, but not both. The current study presents an alternative methodology that provides both benefits u...

Sunlight is the fuel for all solar energy generation technologies. For any generation source and its users , knowledge of the quality and future reliability of the fuel is essential for accurate control and analysis of system performance and to determine the financial viability of projects. Information about the resources and forecasts are conclude...

Four solar cycles show the temporal variations of daily TSI in a composite reconstruction of the 1976-2017 time series based on observations from spaceborne radiometers after corrections and gap-filling. The thick line indicates the 27-day moving average (corresponding to the 27-day mean solar rotation period), and the circled numbers refer to the...

The installation of solar photovoltaic (PV) modules on carports or canopies is a relatively popular application of PV power generation. This advantageously combines power generation and shaded parking for vehicles in the case of carports, or power generation and shelter and shade for people, animals or goods with little waste of land. In parallel,...

Agrivoltaics is a novel application of solar (PV) photovoltaic power generation where the PV modules are installed in the same field as where crops are also cultivated. This is advantageous because this combines land use while keeping attractive productions for both agricultural crops and power generation. Several configurations currently exist for...

Several simulation tools have appeared on the market to estimate the bifacial energy gain (BEG) of bifacial photovoltaic (PV) systems. These tools use two main families of methods that provide a quick estimation of the BEG or a detailed analysis of it, but not both. The current study presents an alternative methodology that provides both benefits u...

The hybridization of several renewable energy power generation sources is a viable option that can improve the use of available resources and space. However, the coexistence of different technologies, with different requirements for operation, can lead to some challenges. In the case of hybridization between a wind farm and an adjacent solar photov...

Site adaptation refers to procedures for correcting systematic errors in an extended period of gridded modeled data using a short period of ground-based measurements used as unbiased reference. Traditionally, site adaptation leverages a single gridded product and issues point predictions. Currently, remote-sensed and reanalysis data are available f...

This study provides performance analysis results obtained from the 10-MW (five 2-MW turbines) Shagaya pilot wind farm located in a desert area of Kuwait, where hot and dusty conditions prevail and constitute engineering challenges. The 2-year operational data analyzed here provide unique results that elucidate the effects of such conditions on turb...

High temperatures and dust accumulation can impact wind turbine performance and increase the maintenance burden and operating cost of wind turbines in desert regions. A novel, detailed analysis method is presented to quantify the separate and total effects of these adverse conditions on the performance of each 2-MW turbine of the 10-MW Shagaya wind...

Considering the current booming interest for the large-scale deployment of bifacial photovoltaic modules, the solar industry now requires accurate estimates of broadband surface albedo at high spatial resolution. In this context, the present study evaluates the adequacy and performance over North America of two Moderate Resolution Imaging Spectrora...

Comprehensive review of the current state of the art in solar radiation measurement and modeling for solar energy applications

Aerosols are part of the attenuation processes that impact solar radiation within the atmosphere. They influence the availability and spectrum of the solar resource for each location at the earth's surface. The present study presents advances in the development of a methodology intended to estimate the aerosol optical depth (AOD) at a given locatio...

Featured Application: The conclusions of this work may prove highly useful in developing easier models to capture the spectral impact on CPV devices. Abstract: A simple index is desirable to assess the effects on both flat-plate and concentrating photovoltaics of natural changes in the solar spectrum. Some studies have suggested that the relationsh...

Accurate estimations of clear-sky direct normal irradiance (DNIcs) and diffuse horizontal irradiance (DIFcs) are crucial in solar resources assessment. This study examines 95 and 88 popular clear-sky irradiance models for their worldwide estimation capability of DNIcs and DIFcs, respectively. Atmospheric inputs are from MERRA-2 reanalysis and irrad...

This global study analyzes how the total column water vapor (in terms of precipitable water, PW) is related to the attenuation of shortwave solar radiation (SWR) using data from the MERRA-2 reanalysis during 2000–2014 and SWR simulations obtained with the REST2 clear-sky radiation model. The water vapor radiative effect (WVRE) on SWR attenuation is...

This paper aims at merging five gridded products of monthly aerosol optical depth (AOD), namely, MERRA-2, MISR, MODIS-Terra, MODIS-Aqua, and VIIRS, over a period of eight years, from 2012 March to 2020 February. Since these individual products offer alternative realizations of the same underlying AOD process, it is beneficial to study them collecti...

Nowadays, the integration of solar power into the electrical grids is vital to increase energy efficiency and profitability. Effective usage of the instable solar production of photovoltaic (PV) systems necessitates trustworthy forecasting information. Actually, this addition can gives an ameliorated service quality if the solar radiation variation...

The field of energy forecasting has attracted many researchers from different fields (e.g., meteorology, data sciences, mechanical or electrical engineering) over the last decade. Solar forecasting is a fast-growing sub- domain of energy forecasting. Despite several previous attempts, the methods and measures used for verification of deterministic...

Annual solar irradiance anomalies (or departures from the long-term mean annual value) have a direct impact on various phases of solar energy projects, from prefeasibility studies to technical deployment decisions [1], [2], [3]. • Anomalies can happen because of normal climate variability or exceptional weather patterns. • This study investigates s...

Standardization and best practices of data sets and models enable the solar energy industry to develop widely accepted protocols adapted to various stages of solar project development and operations. • In collaboration with the International Energy Agency (IEA) Photovoltaic Power Systems (PVPS) Programme Task 16 and ASTM's radiometry subcommittee,...

National Solar Radiation Database (NSRDB). The coefficient of variation (COV) is used to analyze the spatial and temporal (interannual and seasonal) variability. Further, both spatial and temporal long-term variability are analyzed using the Köppen-Geiger climate classification. The temporal variability is found that, on average, the continental Un...

Separation models split diffuse and direct components of solar radiation from the global horizontal radiation. At the moment, all separation models only issue predictions that are deterministic (as opposed to probabilistic). Since the best prediction is necessarily probabilistic, a parametric post-processing framework called the ensemble model outp...