Thesis (MScIng)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The Spier Estate - a wine estate in the Western Cape Province of South Africa -
is engaged in a transition towards operating according to the principles of
sustainable development. Besides changes in social and other environmental
aspects, the company has set itself the goal to be carbon neutral by 2017. To this
end, Spier is considering the on-site generation of electricity from renewable
energy sources. This study was initiated to explore the technical and economic
feasibility of a concentrating solar power plant for this purpose on the estate.
The investigation was carried out to identify the most appropriate solar thermal
energy technology and the dimensions of a system that fulfils the carbon-offset
requirements of the estate. In particular, potential to offset the annual electricity
consumption of the currently 5 570 MWh needed at Spier, using a concentrating
solar power (CSP) system, was investigated. Due to rising utility-provided
electricity prices, and the expected initial higher cost of the generated power, it is
assumed that implemented efficiency measures would lead to a reduction in
demand of 50% by 2017. However, sufficient suitable land was identified to allow
electricity production exceeding today’s demand.
The outcome of this study is the recommendation of a linear Fresnel collector
field without additional heat storage and a saturated steam Rankine cycle power
block with evaporative wet cooling. This decision was based on the system’s
minimal impact on the sensitive environment in combination with the highest
potential for local development. A simulation model was written to evaluate the
plant performance, dimension and cost. The analysis was based on a literature
review of prototype system behaviour and system simulations. The direct normal
irradiation (DNI) data that was used is based on calibrated satellite data. The
result of the study is a levelised cost of electricity (LCOE) of R2.741 per kWh,
which is cost competitive to the power provided by diesel generators, but more
expensive than current and predicted near-future utility rates. The system
contains a 1.8 ha aperture area and a 2.0 MWe power block. Operating the plant
as a research facility would provide significant potential for LCOE reduction with
R2.01 per kWh or less (favourable funding conditions would allow for LCOE of
R1.49 per kWh) appearing feasible, which results in cost competitiveness in
comparison a photovoltaic (PV) solution. Depending on tariff development,
Eskom rates are predicted to reach a similar level between 2017, the time of
commissioning, and the year 2025. The downside is that the plant would not
solely serve the purpose of electricity offsetting for Spier, which may result in a
reduced amount of electricity that may be generated.
Further studies are proposed to refine the full potential of cost reduction by local
development and manufacturing as well as external funding. This includes
identification of suitable technology vendors for plant construction. An EIA is
required to be triggered at an early stage to compensate for its long preparation. / AFRIKAANSE OPSOMMING: Die Spier wynlandgoed in die Wes-Kaap Provinsie van Suid-Afrika is tans in ‘n
oorgangsfase tot besigheids-praktyke gebaseer op volhoubare ontwikkeling.
Afgesien van die sosiale en omgewingsaspekte het die groep hom ook ten doel
gestel om koolstof neutraal te wees teen 2017. Ten einde hierdie doel te bereik,
moet die maatskappy sy algehele elektrisiteitsverbruik vervang met hernubare
bronne. Hierdie studie is dus geloods om die tegniese en ekonomiese uitvoerbaarheid
van 'n gekonsentreerde sonkragstasie op die landgoed te ondersoek.
Hierdie ondersoek is gedoen om die mees toepaslike sontermiese tegnologie en
die grootte van 'n termiese sonkragstelsel te bepaal, wat aan die koolstof
vereistes van die landgoed voldoen. Die potensiaal om die jaarlikse
elektrisiteitsverbruik van 5 570 MWh met 'n gekonsentreerde elektriese sonkragstelsel
te vervang, is ondersoek. Weens die toename in die elektrisiteitsprys en
die verwagte hoërkoste van opgewekte elektrisiteit word aanvaar dat die
implementering van voorgestelde doeltreffendheidsverbeteringe, sal lei tot 'n
afname in die aanvraag na elektrisiteit van tot 50% teen die jaar 2017. Voldoende
beskikbare grond is geïdentifiseer om genoeg elektrisiteit te produseer om die
huidige vraag na elektrisiteit te oorskry.
Die uitkoms van die studie is die aanbeveling van 'n lineêre Fresnel kollektorveld
sonder addisionele warmte storing, asook 'n versadigde stoom Rankine sikluskragblok
met ‘n nat-verdamping verkoelingstelsel. Die besluit is gebaseer op die
stelsel se minimale impak op die omgewing, tesame met die hoogste potensiaal
vir plaaslike ontwikkeling. 'n Simulasie is ontwikkel om die aanleg se
werkverrigting, grootte en koste te evalueer. Die analise is gebaseer op 'n
literatuuroorsig van 'n prototipe stelsel gedrag en stelsel-simulasies. Die direkte
normale sonstralings data wat gebruik is, is gebaseer op gekalibreerde satelliet
data. Die bevinding van die studie is 'n gebalanseerd koste van elektrisiteit van
R2.74 per kWh, wat mededingend is met die koste van elektrisiteit wat deur
diesel kragopwekkers verskaf word, maar is aansienlik duurder as die huidige en
toekomstige voorspellings van Eskom-tariewe. Die stelsel bevat 'n 1.8 ha son
kollektor oppervlakte en 'n 2.0 MWe krag-blok. Daarbenewens, sal die gebruik
van die aanleg as 'n navorsingsfasiliteit die potensiaal hê om die gebalanseerd
koste van elektrisiteit te verminder na R2.01 per kWh of minder (gunstig
befondsing voorwaardes sal gebalanseerd koste van elektrisiteit van R1.49 per
kWh tot gevolg hê), wat mededingend is met die koste van 'n fotovoltaïese
alternatief. Daar word voorspel dat Eskom-tariewe dieselfde sal bly vanaf 2017,
die jaar van inbedryfstelling van die aanleg, tot en met die jaar 2025. Die nadeel
is dat die aanleg nie noodwendig uitsluitlik vir die opwek van elektrisiteit vir Spier
gebruik sal word nie, en daarom kan dit lei tot 'n vermindering in die hoeveelheid
elektrisiteit wat deur die aanleg opgewek word.
Daar word voorgestel dat verdere studies onderneem word om die moontlikheid
van koste-besparings vir die aanleg te ondersoek deur gebruik te maak van
plaaslike ontwikkeling en vervaardiging, asook eksterne befondsing. Dit sluit die
identifisering van geskikte tegnologie verskaffers vir die aanleg-kostruksie in. 'n
Omgewingsimpakstudie, volgens die EIA regulasies, moet ook so gou as
moontlik gedoen word aangesien dit n langsame proses is.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/17809 |
| Date | 12 1900 |
| Creators | Lubkoll, Matti |
| Contributors | Gauche, P., Brent, A. C., University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 90 p. : ill. |
| Rights | Stellenbosch University |
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