Optimisation in plant operations for a 100 MW Central Receiver CSP plant with focus on the plant operating strategies.

De Meyer, Oelof Abraham Jakobus (2018-03)

Thesis (PhD)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: As South Africa progresses towards a more diverse energy mix, it is essential to comprehend both the contribution and implications that renewable energy generating technologies have on the electric grid. Therefore, this dissertation emanated from Eskom’s directive aims to acquire a comprehensive understanding of the technical, financial, and operational aspects of running a plant that is built on concentrating solar central receiver technology. Independent Power Producers (IPPs) and Concentrated Solar Power (CSP) plant operators across the globe predominantly adopt the Maximise Power Generation operating strategy. It is necessary to determine the means to optimise the plant operations as a varying operating strategy is envisioned for the plant. Therefore, this research investigated the effects of an array of varying operating strategies imposed upon the plant, which is an essential exercise to determine the possible role of CSP within the South African electric grid. Three boundary conditions determine the operations of a CSP plant: weather conditions; plant status; and operating strategy. After an extensive literature review, it is established that no publically available model is available to optimise the plant operations under the aforementioned conditions. Therefore, a simulation model was developed in the current research to optimise the plant under these boundary conditions. The basic design of Eskom’s 100 MW CSP project was used as the reference plant in developing the simulation model. Subsequently, the simulation results and performance curves of each subsystem within the plant, i.e. the heliostat field, receiver and power block, are validated against other commercially available simulation models. The operational logic is implemented in the validated model to objectively simulate the plant operations considering the specified boundary conditions. The developed simulation model successfully demonstrated through simulation the effects that (i) weather conditions, (ii) plant status and (iii) operating strategies have on both, the plant performance and operational capabilities of the central receiver technology. The advantages that this model offers over the other similar simulation models available in literature are as follows: provides a detailed, up to seven-day forecast, of the plant operations; implements time resolution of 15 minutes increasing the transients and results accuracy; provides user flexibility to specify the precise boundary conditions imposed on plant operations; offers capability of comparing various simulations or operating strategies by providing key performance and financial indicators. The dissertation and developed model offers Eskom and the system operator with the required tools to address the specific business needs, also identified by the Eskom Power Plant Engineering Institute (EPPEI) program. The resulting cost of generation, performance indicators and operational capabilities demonstrated are to assist in future Power Purchase Agreements (PPA) and national policy formulations.

AFRIKAANSE OPSOMMING: Met Suid-Afrika wat tans besig is om sy energiesamevatting te diversifiseer, is dit noodsaaklik om ’n allesomvattende geheelbeeld oor die bydrae en implikasies wat hernubare energie krag-opwek tegnologieë op die elektriese netwerk bied. Hierdie tesis het daarom voortgespruit uit Eskom se leiding om ’n volle begrip te kry oor die tegniese, finansiële, en operasionele aspekte van ’n kragstasie wat gebruik maak van die gekonsentreerde sonsentrale-opvangertegnologie. Onafhanklike Krag Produsente (OKP) en Gekonsentreerde Sonkrag (GSK) stasieoperateurs reg oor die wêreld implementeer gewoonlik die ‘Maksimum Krag Opwekking’ bedryfstrategie. Hierdie tesis ondersoek die effekte op die kragstasie wanneer ’n verskeidenheid van bedryfstrategieë geïmplimenteer word, ’n noodsaaklike oefening om die potensiale rol van GSK te bepaal in Suid-Afrika se elektriese netwerk. Met ’n verskeidenheid van bedryfstrategieë beoog vir die kragstasie, is dit dus noodsaaklik om die optimalisering van die kragstasie se bedrywighede te bepaal. Drie randvoorwaardes bepaal die optimalisering van die kragstasie se bedrywighede: die weerstoestande; status van die kragstasie; en bedryfstrategie. Die literatuuroorsig het aangewys dat daar geen publieke simulasiemodelle beskikbaar is om te voldoen aan die optimalisering van die kragstasie se bedrywighede met hierdie randvoorwaardes nie. Daarom was ’n simulasiemodel geskep om die optimalisering aan te spreek. Die basiese ontwerp van Eskom se 100 MW GSK projek was gebruik as die verwysingskragstasie in die ontwikkeling van die simulasiemodel. Gevolglik was die simulasieresultate en prestasiekrommes van elke substelsel in die kragstasie, nl. die heliostaatveld, ontvanger en krag blok, bekragtig teenoor ander kommersiële beskikbare simulasiemodelle. Die operasionele logika is geïmplimenteer in die bekragtige simulasiemodel om objektief die kragstasie se bedrywighede te simuleer met verskeie bedryfstrategieë. Die simulasiemodel kon dus suksesvol demonstreer, deur simulasie, die effekte wat (i) die weerstoestande, (ii) status van die kragstasie en, (iii) bedryfstrategie plaas op die kragstasie se prestasie en operasionele vermoëns. Die voordeel wat die simulasiemodel bied oor ander soortgelyke simulasiemodelle beskikbaar in literatuur, is soos volg: bied 'n gedetailleerde, tot sewe-dae voorspelling, van die kragstasie se bedrywighede; implementeer ‘n tydresolusie van 15 minute om die kragstasie oorgang te verbeter asook beter akkuraatheid; bied die gebruiker vryheid om die presiese randvoorwaardes te spesifiseer wat op kragstasie se bedrywighede geplaas word; en die simulasiemodel is in staat om verskillende simulasies of bedryfstrategieë te vergelyk deur middel van prestasie en finansiële aanwysers. Die tesis en ontwikkelde simulasiemodel bied Eskom en die elektriese netwerkoperateur die noodsaaklike gereedskap om die spesifieke besigheids-behoeftes aan te spreek, ook deur die Eskom Kragstasie Ingenieursinstituut (EKII) geïdentifiseer. Die simulasiemodel se resultate, nl. koste van kragopwekking, prestasie-aanwysers en operasionele vermoëns, kan bydrae met toekomstige kragaankoop-ooreenkomste en nasionale beleidsformulerings.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103811
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