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Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa

Thesis (MEng)--Stellenbosch University, 2014.

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Main Author: Madaly, Kamalahasen
Other Authors: Hoffmann, J.
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2014
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access_status_str Open Access
author Madaly, Kamalahasen
author2 Hoffmann, J.
author_browse Hoffmann, J.
Madaly, Kamalahasen
author_facet Hoffmann, J.
Madaly, Kamalahasen
author_sort Madaly, Kamalahasen
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MEng)--Stellenbosch University, 2014.
format Thesis
id oai:scholar.sun.ac.za:10019.1/86276
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:40:53.839Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
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source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/86276 Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa Madaly, Kamalahasen Hoffmann, J. Gauche, Paul Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Heat storage Levelised electricity cost (LEC) Solar power plants Solar energy Central receiver system (CRS) Dissertations -- Mechanical and mechatronic engineering UCTD Theses -- Mechanical and mechatronic engineering Thesis (MEng)--Stellenbosch University, 2014. ENGLISH ABSTRACT: Central receiver power plants generate renewable electricity by exploiting the energy provided by the sun. The conditions experienced in the Northern Cape region of South Africa provide the ideal conditions for the development of these plants. Without a storage medium these plants have capacity factors in the range of 25-30%. The inclusion of a thermal energy storage medium provides the ability to increase the capacity factors of these plants. Although storage increases the costs, it results in better utilisation of the power block and a decrease in the levelised electricity cost (LEC). Eskom intends building a 100MWe central receiver dry cooled power plant in the Upington region. This research identifies the appropriate storage medium and ideal storage capacity to achieve the lowest LEC. A literature survey was performed to identify the different methods of storage that are available. The different storage methods were evaluated and the best storage medium for a central receiver power plant based on the developments of the various storage technologies was identified. To determine the costs associated with a central receiver power plant, data published by NREL was used. Different plant parameters were required to evaluate the costs. A power plant model based on efficiencies and energy balances was created to determine the required plant parameters. It provided the ability to determine the effect of changing different plant parameters on the LEC and estimate the plant output. The power block parameters were initially varied to determine the most efficient power block configuration. Once the most efficient power block configuration was identified the solar field and storage parameters were varied to determine the plant configuration which resulted in the lowest LEC. The most efficient power block configuration of 0.4206 was found for a system comprising of six feedwater heaters with the feedwater temperature of 230°C, main steam pressure 140 bar and an exit steam generator salt temperature of 290°C. A solar multiple of 3.0 with 16 hours of storage resulted in a LEC of R1.41/kWh with no system constraints. A capacity factor constraint of 60% resulted in a solar multiple of 1.8 with 8 hours of storage and a LEC of R1.78/kWh. AFRIKAANSE OPSOMMING: Sonkragaanlegte met sentrale ontvangers wek hernubare elektrisiteit op deur sonenergie te ontgin. Die klimaat in die Noord Kaap-streek van Suid-Afrika is ideaal vir die oprigting van hierdie aanlegte. Sonder ’n bergingsmedium is die kapasiteitsfaktore van sulke aanlegte ongeveer 25-30%. Met die insluiting van ’n bergingsmedium vir termiese energie kan die kapasiteitsfaktore egter verhoog word. Hoewel berging aanlegkoste verhoog, lei dit terselfdertyd tot beter aanwending van die kragblok en ’n afname in die konstante eenheidskoste van elektrisiteit (LEC). Eskom beplan om ’n droogverkoelde kragaanleg van 100 MW met ’n sentrale ontvanger in die Upington-streek op te rig. Hierdie navorsing was dus daarop toegespits om die mees geskikte bergingsmedium en ideale bergingskapasiteit te bepaal om die laagste moontlike LEC uit die aanleg te verkry. ’n Literatuurstudie is onderneem om die verskeie beskikbare bergingsmetodes te bestudeer. Die verskillende metodes is beoordeel, waarna die beste bergingsmedium vir ’n kragaanleg met ’n sentrale ontvanger op grond van die ontwikkelings in die verskillende bergingstegnologieë bepaal is. Om die koste van ’n kragaanleg met ’n sentrale ontvanger te bepaal, is gepubliseerde data van die Amerikaanse Nasionale Laboratorium vir Hernubare Energie (NREL) gebruik. Verskillende aanlegparameters was egter nodig om die koste te beoordeel. Dié parameters is gevolglik bepaal deur ’n kragaanlegmodel op grond van doeltreffendheidsfaktore en energiebalanse te skep. Sodoende kon vasgestel word watter uitwerking veranderinge in die verskillende parameters op die LEC sou hê, en kon die aanleguitset geraam word. Die kragblokparameters is aanvanklik afgewissel om die doeltreffendste kragbloksamestel te bepaal. Nadat dít bepaal is, is die sonenergieveld en bergingsparameters weer afgewissel om vas te stel watter aanlegsamestel die laagste LEC tot gevolg sou hê. Die beste termiese benuttingsgraad is behaal vir ʼn stoom siklus met ses water verhitters en ʼn water temperatuur van 230 °C by die ketel se inlaat, ʼn stoom druk van 140 bar, en sout uitlaat temperatuur van 290 °C. ʼn Vermenigvuldigingsfaktor van drie vir die heliostaat veld, en 16 uur termiese energie storing gee ʼn opwekkingskoste van R 1.41/kW/h indien daar geen beperkings op die grootte of koste van die stelsel geplaas word nie. Indien die kapitaal uitgawe ʼn perk van 60 % op die kapasitiet van die stelsel plaas, verander die optimale ontwerpspunt na ʼn vermenigvuldigingsfaktor van 1.8, en die termiese stoorkapasitiet verlaag na 8 uur. In hierdie geval is die opwekkingskoste R 1.78/kWh. 2014-04-16T17:28:33Z 2016-03-31T03:00:12Z 2014-04 Thesis http://hdl.handle.net/10019.1/86276 en_ZA Stellenbosch University xiv, 85 pages : illustrations application/pdf application/pdf Stellenbosch : Stellenbosch University
spellingShingle Heat storage
Levelised electricity cost (LEC)
Solar power plants
Solar energy
Central receiver system (CRS)
Dissertations -- Mechanical and mechatronic engineering
UCTD
Theses -- Mechanical and mechatronic engineering
Madaly, Kamalahasen
Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title_full Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title_fullStr Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title_full_unstemmed Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title_short Identifying the optimum storage capacity for a 100-MWe concentrating solar power plant in South Africa
title_sort identifying the optimum storage capacity for a 100 mwe concentrating solar power plant in south africa
topic Heat storage
Levelised electricity cost (LEC)
Solar power plants
Solar energy
Central receiver system (CRS)
Dissertations -- Mechanical and mechatronic engineering
UCTD
Theses -- Mechanical and mechatronic engineering
url http://hdl.handle.net/10019.1/86276
work_keys_str_mv AT madalykamalahasen identifyingtheoptimumstoragecapacityfora100mweconcentratingsolarpowerplantinsouthafrica