Sensitivity of the solar resource in solar tower plants to aerosols and water vapor

Elías, T.; Ramon, Didier; Brau, Jean-Florian; Moulana, Mustapha

doi:10.1063/1.5117703

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…The main impact of aerosols is to attenuate the direct component of the solar radiation incident at surface level. Input spectral AOT constrains efficiently this impact [Elias et al, 2019;Elias et al, 2021] as it depends on aerosol load and nature, aerosol nature driving the AOT spectral dependency. However input spectral AOT poorly constrains the aerosol-scattering proportion which significantly affects DifHI.…”

Section: Introductionmentioning

confidence: 99%

Regional validation of the solar irradiance tool SolaRes in clear-sky conditions, with a focus on the aerosol module

Elias,

Ferlay,

Chesnoiu

et al. 2024

Preprint

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Abstract. The objective of the paper is to validate SolaRes (Solar Resource estimate) in clear-sky conditions, and to examine the aerosol influence on the differences between observation and estimate. SolaRes has the ambition to fulfil both research and industrial applications exploiting downwelling solar radiation at surface level. Consistently with solar resource applications, we show the capacity of SolaRes to reproduce the angular behaviour of the angular field, by validating not only global horizontal irradiance (GHI), but also direct normal irradiance (DNI), diffuse horizontal irradiance (DifHI), global and diffuse irradiance in tilted plane (GTI, DifTI), and even the circumsolar contributions. Computations are made with the SMART-G radiative transfer code, taking spectral aerosol optical thickness (AOT) data sets as input, which are delivered by the Aerosol Robotic network (AERONET) and the Copernicus Atmospheric Monitoring Service (CAMS). A mixture of two aerosol models is required to compute aerosol optical properties. Measurements for validation are made at two sites in Northern France. Clear-sky is identified by two methods to show its influence: 1) a method reproducing the AOT variability conditions, and 2) a stricter method eliminating some residual cloud influence but also conditions with largest AOT. SolaRes is validated according to comparison scores found in the literature, with the (relative) root mean square difference (RMSD) in GHI as low as 1 %, and the mean bias difference (MBD) which could be 0 %. Angular behaviour is reproduced with satisfying scores. The circumsolar contribution improves MBD in DNI and DifHI, by 1 % and 4 % respectively, as well as RMSD by ~0.5 %. MBD in DNI is around -1 % and RMSD around 2 %, and MBD in DifHI is 2 % and RMSD around 9 %. RMSD and MBD in both DNI and DifHI are larger than in GHI because they are more sensitive to the aerosol and surface properties. DifTI measured in a vertical plane facing South is reproduced with a RMSD of 8 %, similar to DifHI. It is suggested a strong influence of reflection by not only ground surface but also surrounding buildings, increasing the albedo from 0.13 to 0.35. The sensitivity study on the aerosol parameterisation shows that the spectral AOT contains enough information for best quality in DNI retrieval. The choice of aerosol models in the parameterisation has an influence in RMSD smaller than 0.7 %. Complementary information on angular scattering and aerosol absorption has a significant influence in GHI by reducing RMSD by ~0.5 %, and MBD by ~0.8 %. The uncertainty on the data source has a significant influence. The CAMS data set increases the RMSD in DNI by 5 %, but has has less influence in GHI, by increasing RMSD by ~1 % and MBD by ~0.4 %. RMSD in GHI still remains slightly smaller than state-of-the-art methods.

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Section: Introductionmentioning

confidence: 99%

Regional validation of the solar irradiance tool SolaRes in clear-sky conditions, with a focus on the aerosol module

Elias,

Ferlay,

Chesnoiu

et al. 2024

Preprint

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“…Usually, meteorological data sets, including irradiance measurements or typical meteorological years, are acquired within the planning phase for a CSP project. As it is not always possible to also perform on-site measurements of the atmospheric extinction additionally to the standard measurement setup during the resource assessment process, the need of according modeling methods arose during the last few years, and different methods have been presented [12][13][14][15][16][17][18]. The different models use, for example, the aerosol optical depth (AOD) of, e.g., the AERONET network, remote sensing data of MODIS, or water vapor data sets.…”

Section: Introductionmentioning

confidence: 99%

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

Hanrieder¹,

Ghennioui

Wilbert³

et al. 2020

Energies

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Attenuation of solar radiation between the receiver and the heliostat field in concentrated solar power (CSP) tower plants can reduce the overall system performance significantly. The attenuation varies strongly with time and the average attenuation at different sites might also vary strongly from each other. If no site specific attenuation data is available, the optimal plant design cannot be determined and rough estimations of the attenuation effect are required leading to high uncertainties of yield analysis calculations. The attenuation is caused mainly by water vapor content and aerosol particles in the lower atmospheric layer above ground. Although several on-site measurement systems have been developed during recent years, attenuation data sets are usually not available to be included during the plant project development. An Atmospheric Attenuation (AATTENUATION) model to derive the atmospheric transmittance between a heliostat and receiver on the basis of common direct normal irradiance (DNI), temperature, relative humidity, and barometric pressure measurements was developed and validated by the authors earlier. The model allows the accurate estimation of attenuation for sites with low attenuation and gives an estimation of the attenuation for less clear sites. However, the site-dependent coefficients of the AATTENUATION model had to be developed individually for each site of interest, which required time-consuming radiative transfer simulations, considering the exact location and altitude, as well as the pre-dominant aerosol type at the location. This strongly limited the application of the model despite its typically available input data. In this manuscript, a look-up table (LUT) is presented which enables the application of the AATTENUATION model at the site of interest without the necessity to perform the according complex radiative transfer calculations for each site individually. This enables the application of the AATTENUATION model for virtually all resource assessments for tower plants and in an operational mode in real time within plant monitoring systems around the world. The LUT also facilitates the generation of solar attenuation maps on the basis of long-term meteorological data sets which can be considered during resource assessment for CSP tower plant projects. The LUTs are provided together with this manuscript as supplementary files. The LUT for the AATTENUATION model was developed for a solar zenith angle (SZA) grid of 1°, an altitude grid of 100 m, 7 different standard aerosol types and the standard AFGL atmospheres for mid-latitudes and the tropics. The LUT was tested against the original version of the AATTENUATION model at 4 sites in Morocco and Spain, and it was found that the additional uncertainty introduced by the application of the LUT is negligible. With the information of latitude, longitude, altitude above mean sea level, DNI, relative humidity (RH), ambient temperature (Tair), and barometric pressure (bp), the attenuation can be now derived easily for each site of interest.

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“…Ref. [18] analyzed the inter annual variability of aerosol optical depth (AOD) and irradiance in Quarzazate (Morocco) and its influence on the characterization of extinction conditions for a certain site.…”

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confidence: 99%

Atmospheric Transmittance Model Validation for CSP Tower Plants

Hanrieder¹,

Ghennioui

Merrouni

et al. 2019

Remote Sensing

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In yield analysis and plant design of concentrated solar power (CSP) tower plants, increased uncertainties are caused by the mostly unknown solar attenuation between the concentrating heliostat field and the receiver on top of the tower. This attenuation is caused mainly by aerosol particles and water vapor. Various on-site measurement methods of atmospheric extinction in solar tower plants have been developed during recent years, but during resource assessment for distinct tower plant projects in-situ measurement data sets are typically not available. To overcome this lack of information, a transmittance model (TM) has been previously developed and enhanced by the authors to derive the atmospheric transmittance between a heliostat and receiver on the basis of common direct normal irradiance (DNI), temperature, relative humidity and barometric pressure measurements. Previously the model was only tested at one site. In this manuscript, the enhanced TM is validated for three sites (CIEMAT’s Plataforma Solar de Almería (PSA), Spain, Missour, Morocco (MIS) and Zagora, Morocco (ZAG)). As the strongest assumption in the TM is the vertical aerosol particle profile, three different approaches to describe the vertical profile are tested in the TM. One approach assumes a homogeneous aerosol profile up to 1 kilometer above ground, the second approach is based on LIVAS profiles obtained from Lidar measurements and the third approach uses boundary layer height (BLH) data of the European Centre for Medium-Range Weather Forecasts (ECMWF). The derived broadband transmittance for a slant range of 1 km ( T 1 k m ) time series is compared with a reference data set of on-site absorption- and broadband corrected T 1 k m derived from meteorological optical range (MOR) measurements for the temporal period between January 2015 and November 2017. The absolute mean bias error (MBE) for the TM’s T 1 k m using the three different aerosol profiles lies below 5% except for ZAG and one profile assumption. The MBE is close to 0 for PSA and MIS assuming a homogeneous extinction coefficient up to 1 km above ground. The root mean square error (RMSE) is around 5–6% for PSA and ZAG and around 7–8% for MIS. The TM performs better during summer months, during which more data points have been evaluated. This validation proves the applicability of the transmittance model for resource assessment at various sites. It enables the identification of a clear site with high T 1 k m with a high accuracy and provides an estimation of the T 1 k m for hazy sites. Thus it facilitates the decision if on-site extinction measurements are necessary. The model can be used to improve the accuracy of yield analysis of tower plants and allows the site adapted design.

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Sensitivity of the solar resource in solar tower plants to aerosols and water vapor

Cited by 6 publications

References 17 publications

Regional validation of the solar irradiance tool SolaRes in clear-sky conditions, with a focus on the aerosol module

Regional validation of the solar irradiance tool SolaRes in clear-sky conditions, with a focus on the aerosol module

AATTENUATION—The Atmospheric Attenuation Model for CSP Tower Plants: A Look-Up Table for Operational Implementation

Atmospheric Transmittance Model Validation for CSP Tower Plants

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