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Wave Energy Distribution Across the Agulhas Bank, A Source of Renewable Energy for a Seawater Pumped Storage Scheme

Thesis

Title: Wave Energy Distribution Across the Agulhas Bank, A Source of Renewable Energy for a Seawater Pumped Storage Scheme
Author:
Francisco, F.
Publication Date:
Thesis Type:
Master's Thesis
Academic Department:
Oceanography
Pages:
117
Affiliation
University of Cape Town
Technology:
Marine Energy, Wave
Receptor:
Human Dimensions
Language:
English

Document Access

Website:
External Link
Attachment:
Access File

Citation

Francisco, F. (2013). Wave Energy Distribution Across the Agulhas Bank, A Source of Renewable Energy for a Seawater Pumped Storage Scheme (Master's Thesis). University of Cape Town.
@mastersthesis{Francisco-2013-1475102,
author = {Francisco, F},
title = {Wave Energy Distribution Across the Agulhas Bank, A Source of Renewable Energy for a Seawater Pumped Storage Scheme },
school = {University of Cape Town},
year = {2013},
month = {jan},
url = {https://open.uct.ac.za/bitstream/handle/11427/6585/thesis_sci_2013_francisco_f.pdf?sequence=1},
keywords = {Marine Energy, Wave, Human Dimensions},
}
Export Citation to BibTex
TY - THES
TI - Wave Energy Distribution Across the Agulhas Bank, A Source of Renewable Energy for a Seawater Pumped Storage Scheme
AU - Francisco, F
AB - This study was undertaken to assess whether the available and recoverable wave power density resource on the Agulhas Bank (South Africa) is sufficient to support a Pumped Storage Scheme (PSS). We used 5 months of insitu wave data collected in a depth of 80 m off Cape Agulhas, Mossel Bay, Tsitsikamma and Cape Recife, together with model wave data from the National Centre for Environmental Prediction (NCEP) - WAVEWATCH III which was reanalysed by the French Research Institute for Exploitation of the Sea (IFREMER) - IWOAGA. The wave power density resource (P) was estimated by calculating the wave energy flux across a unit diameter circle of the wave field, and the resource available by the lateral transfer of wave energy along a linear array of wave energy converting devices. The results showed that Cape Agulhas had the most available P (75% for 40 kW/m, 25% for 17 kW/m, with an average of 31 kW/m) followed by Mossel Bay (75% for 34 kW/m, 25% for 14 kW/m, with an average of 25.2 kW/m), Tsitsikamma (75% for 32 kW/m, 25% for 13 kW/m, with an average of 25.0 kW/m), and Cape Recife (75% for 30 kW/m, 25% for 12 kW/m, with an average of 23.7 kW/m). For the entire nearshore domain, the most frequent waves had values of P between 30 kW/m – 50 kW/m, with the dominant direction of propagation from the southwest. On average, the diurnal cycle was characterised by a peak in energy in the evening nearshore and in the afternoon offshore. The seasonal cycle was characterised by a peak in winter (40 – 50 kW/m) and trough in summer (20 – 30 kW/m). The interannual variability signal had a strong correlation with regional Sea Level Pressure (SLP), surface westerlies winds, and regional sea surface currents. It is also correlated to El Niño Southern Oscillation (NINO3) and the Southern Annular Mode (SAM). In terms of the total annual wave energy resource (P), approximately 380 TWh/yr, are available near the 80 and 128 m water depths. For the PSS, it was estimated that for a moderate flow rate of 50 m3s-1, the required power to pump sea water to an upper reservoir with a volume of 5 and 15 million m3 is approximately 43 and 150 MW. The pumping process would take between 28 and 82 hours. This study concludes that the entire Agulhas Bank has indeed sufficient wave energy resource to supply a large scale PSS.
DA - 2013/01//
PY - 2013
SP - 117
PB - University of Cape Town
UR - https://open.uct.ac.za/bitstream/handle/11427/6585/thesis_sci_2013_francisco_f.pdf?sequence=1
LA - English
M3 - Master's Thesis
KW - Marine Energy
KW - Wave
KW - Human Dimensions
ER -
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Abstract

This  study  was  undertaken  to  assess  whether  the  available  and  recoverable  wave  power  density resource  on  the  Agulhas  Bank  (South  Africa)  is  sufficient  to  support  a  Pumped  Storage  Scheme  (PSS). We  used  5  months  of  insitu  wave  data  collected  in  a  depth  of  80  m  off  Cape  Agulhas,  Mossel  Bay, Tsitsikamma  and  Cape  Recife,  together  with  model  wave  data  from  the  National  Centre  for Environmental  Prediction  (NCEP)  -  WAVEWATCH  III  which  was  reanalysed  by  the  French  Research Institute  for  Exploitation  of  the  Sea  (IFREMER)  -  IWOAGA.  The  wave  power  density  resource  (P)  was estimated  by  calculating  the  wave  energy  flux  across  a  unit  diameter  circle  of  the  wave  field,  and  the resource  available  by  the  lateral  transfer  of  wave  energy  along  a  linear  array  of  wave  energy converting  devices.  The  results  showed  that  Cape  Agulhas  had  the  most  available  P  (75%  for  40 kW/m,  25%  for  17  kW/m,  with  an  average  of  31  kW/m)  followed  by  Mossel  Bay  (75%  for  34  kW/m, 25%  for  14  kW/m,  with  an  average  of  25.2  kW/m),  Tsitsikamma  (75%  for  32  kW/m,  25%  for  13 kW/m,  with  an  average  of  25.0  kW/m),  and  Cape  Recife  (75%  for  30  kW/m,  25%  for  12  kW/m,  with an  average  of  23.7  kW/m).  For  the  entire  nearshore  domain,  the  most  frequent  waves  had  values  of  P between  30  kW/m  –  50  kW/m,  with  the  dominant  direction  of  propagation  from  the  southwest.  On average,  the  diurnal  cycle  was  characterised  by  a  peak  in  energy  in  the  evening  nearshore  and  in  the afternoon  offshore.  The  seasonal  cycle  was  characterised  by  a  peak  in  winter  (40  –  50  kW/m)  and trough  in  summer  (20  –  30  kW/m).  The  interannual  variability  signal  had  a  strong  correlation  with regional  Sea  Level  Pressure  (SLP),  surface  westerlies  winds,  and  regional  sea  surface  currents.  It  is also  correlated  to  El  Niño  Southern  Oscillation  (NINO3)  and  the  Southern  Annular  Mode  (SAM).  In terms  of  the  total  annual  wave  energy  resource  (P),  approximately  380  TWh/yr,  are  available  near  the 80  and  128  m  water  depths.  For  the  PSS,  it  was  estimated  that  for  a  moderate  flow  rate  of  50  m3s-1,  the required  power  to  pump  sea  water  to  an  upper  reservoir  with  a  volume  of  5  and  15  million  m3  is approximately  43  and  150  MW.  The  pumping  process  would  take  between  28  and  82  hours.  This  study concludes  that  the  entire  Agulhas  Bank  has  indeed  sufficient  wave  energy  resource  to  supply  a  large scale PSS.