Assessing the impacts of free-stream turbines for electricity generation

Due to a number of factors including energy security and climate change, there is an urgent need to transition the global energy supply to renewables. Two potential sources are tidal-stream and hydrokinetic power, utilizing free-stream water turbines as generating devices. Much of the interest in ti...

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Main Author: Atwater, Joel Fraser
Language:English
Published: University of British Columbia 2015
Online Access:http://hdl.handle.net/2429/54999
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spelling ndltd-UBC-oai-circle.library.ubc.ca-2429-549992018-01-05T17:28:35Z Assessing the impacts of free-stream turbines for electricity generation Atwater, Joel Fraser Due to a number of factors including energy security and climate change, there is an urgent need to transition the global energy supply to renewables. Two potential sources are tidal-stream and hydrokinetic power, utilizing free-stream water turbines as generating devices. Much of the interest in tidal-stream power comes from resource assessments that suggest that significant amounts of electricity could be produced from tidal currents flowing through straits. These assessments inventoried the kinetic energy flux and do not account for flow reduction due to turbine resistance. As such, they do not present a realistic picture of the resource. An analytical model for flow reduction in tidal straits demonstrates that only 38% of the natural fluid power is theoretically extractible. This model does not capture the behaviour of bays, lagoons, or the open ocean. Maximum power production requires flows to be reduced to 58% of natural and if the flow is kept above 95% of nominal (due to environmental regulations) less than 10% of the total power is available. A large laboratory experiment was built to test the analytical model and the results agree with the analytical model. Predicted future levelized cost of energy from tidal generation in straits is an interplay of reduced production due flow reduction competing with decreasing technology costs. This is modelled, indicating levelized costs of energy will drop initially, then rise due to flow reduction. Considering hydrokinetic power near hydropower stations, a 1D model used Seton Canal data to simulate the installation of turbines. The results show that the installation of hydrokinetic turbines would decrease the output of the existing powerhouse. Furthermore, the decrease in hydroelectric production is greater than the hydrokinetic production. Thus, installing hydrokinetic turbines would cause a net energy loss. In conclusion, there are three key recommendations: 1. Policy makers are cautioned in embracing tidal resource assessments that are based solely on kinetic energy flux. 2. Project proponents and regulators are advised to study far-field effects of any proposed free-stream turbine installation. 3. Developers, investors, and policy makers are cautioned towards assuming that the long-term cost of energy from tidal power will decrease. Applied Science, Faculty of Civil Engineering, Department of Graduate 2015-10-13T18:08:06Z 2015-10-24T06:51:29 2015 2015-11 Text Thesis/Dissertation http://hdl.handle.net/2429/54999 eng Attribution-NonCommercial-NoDerivs 2.5 Canada http://creativecommons.org/licenses/by-nc-nd/2.5/ca/ University of British Columbia
collection NDLTD
language English
sources NDLTD
description Due to a number of factors including energy security and climate change, there is an urgent need to transition the global energy supply to renewables. Two potential sources are tidal-stream and hydrokinetic power, utilizing free-stream water turbines as generating devices. Much of the interest in tidal-stream power comes from resource assessments that suggest that significant amounts of electricity could be produced from tidal currents flowing through straits. These assessments inventoried the kinetic energy flux and do not account for flow reduction due to turbine resistance. As such, they do not present a realistic picture of the resource. An analytical model for flow reduction in tidal straits demonstrates that only 38% of the natural fluid power is theoretically extractible. This model does not capture the behaviour of bays, lagoons, or the open ocean. Maximum power production requires flows to be reduced to 58% of natural and if the flow is kept above 95% of nominal (due to environmental regulations) less than 10% of the total power is available. A large laboratory experiment was built to test the analytical model and the results agree with the analytical model. Predicted future levelized cost of energy from tidal generation in straits is an interplay of reduced production due flow reduction competing with decreasing technology costs. This is modelled, indicating levelized costs of energy will drop initially, then rise due to flow reduction. Considering hydrokinetic power near hydropower stations, a 1D model used Seton Canal data to simulate the installation of turbines. The results show that the installation of hydrokinetic turbines would decrease the output of the existing powerhouse. Furthermore, the decrease in hydroelectric production is greater than the hydrokinetic production. Thus, installing hydrokinetic turbines would cause a net energy loss. In conclusion, there are three key recommendations: 1. Policy makers are cautioned in embracing tidal resource assessments that are based solely on kinetic energy flux. 2. Project proponents and regulators are advised to study far-field effects of any proposed free-stream turbine installation. 3. Developers, investors, and policy makers are cautioned towards assuming that the long-term cost of energy from tidal power will decrease. === Applied Science, Faculty of === Civil Engineering, Department of === Graduate
author Atwater, Joel Fraser
spellingShingle Atwater, Joel Fraser
Assessing the impacts of free-stream turbines for electricity generation
author_facet Atwater, Joel Fraser
author_sort Atwater, Joel Fraser
title Assessing the impacts of free-stream turbines for electricity generation
title_short Assessing the impacts of free-stream turbines for electricity generation
title_full Assessing the impacts of free-stream turbines for electricity generation
title_fullStr Assessing the impacts of free-stream turbines for electricity generation
title_full_unstemmed Assessing the impacts of free-stream turbines for electricity generation
title_sort assessing the impacts of free-stream turbines for electricity generation
publisher University of British Columbia
publishDate 2015
url http://hdl.handle.net/2429/54999
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