title: Exploration of a digital twin concept for income maximisation of the Waikaremoana Power Scheme

authors: Ly, Seng Theng

abstract: Digital twins are digital emulations of real-world objects or systems which mirrors the asset in terms of both behaviour and likeness. Genesis Energy Ltd, an electricity generation company in New Zealand, is interested in developing a digital twin for one of its hydropower assets, the Waikaremoana Power Scheme (WPS). The scheme is a multi-lake cascading system in the North Island with a generation capacity of 138 MW using seven turbines. The ultimate goal for digital twin development with Genesis is to create a tool capable of providing decision making support for traders managing the utilisation of the WPS in the NZ electricity market to maximise income and efficiency while minimising losses. This project is a tentative exploration into how an early digital twin concept could be built for the WPS with the end objective of maximising utilisation through optimising unit commitment and scheduling.
Plant data accuracy and reliability was examined as it is a foundational element to any digital twin. It was found that the WPS possessed accurate instruments for parameters like power output and water levels but relied on correlations for many flow readings around the scheme. Data sampling methods were also examined, and it was found that averaged data was better at short sampling intervals due to reduction of noise.
A flow model was built in Microsoft Excel using a first principles-based approach, assembled using mass and energy balances along with characteristic equations for the scheme. The accuracy of the model was tested against net flow values via lake sensor readings. It was found that on average, there was a difference of around 2 m3/s for all three lakes but increased in proportion to the model net flow rate. As part of the flow model, the efficiency characteristic functions were found using a regression refinement process, starting from linear regression refining eventually to a multivariable linear (polynomial) model. The model was validated using test data from each of the generation units with excellent or good fits found for all units. .
A profit-based optimisation formulation was developed based on literature and the flow model developed. The formulation was applied to a simplified case comprising of a single unit, lake, and time slice problem and testing the relationship between spot price and water value. The problem was solved using Excel Solver and a GRG nonlinear method. Depending on whether the spot price was greater or smaller than water value, the optimiser chose to generate at maximum efficiency before increasing to maximum output as spot price rose. The optimisation encountered difficulties when extending the problem to include multiple units. The Excel Solver was unable to find the global optimum without increasing compute times to unacceptable levels. To proceed further with this optimisation problem, it would need to be moved to a platform with more complex solvers.

text: Exploration of a digital twin concept for income maximisation of the Waikaremoana Power Scheme Digital twins are digital emulations of real-world objects or systems which mirrors the asset in terms of both behaviour and likeness. Genesis Energy Ltd, an electricity generation company in New Zealand, is interested in developing a digital twin for one of its hydropower assets, the Waikaremoana Power Scheme (WPS). The scheme is a multi-lake cascading system in the North Island with a generation capacity of 138 MW using seven turbines. The ultimate goal for digital twin development with Genesis is to create a tool capable of providing decision making support for traders managing the utilisation of the WPS in the NZ electricity market to maximise income and efficiency while minimising losses. This project is a tentative exploration into how an early digital twin concept could be built for the WPS with the end objective of maximising utilisation through optimising unit commitment and scheduling.
Plant data accuracy and reliability was examined as it is a foundational element to any digital twin. It was found that the WPS possessed accurate instruments for parameters like power output and water levels but relied on correlations for many flow readings around the scheme. Data sampling methods were also examined, and it was found that averaged data was better at short sampling intervals due to reduction of noise.
A flow model was built in Microsoft Excel using a first principles-based approach, assembled using mass and energy balances along with characteristic equations for the scheme. The accuracy of the model was tested against net flow values via lake sensor readings. It was found that on average, there was a difference of around 2 m3/s for all three lakes but increased in proportion to the model net flow rate. As part of the flow model, the efficiency characteristic functions were found using a regression refinement process, starting from linear regression refining eventually to a multivariable linear (polynomial) model. The model was validated using test data from each of the generation units with excellent or good fits found for all units. .
A profit-based optimisation formulation was developed based on literature and the flow model developed. The formulation was applied to a simplified case comprising of a single unit, lake, and time slice problem and testing the relationship between spot price and water value. The problem was solved using Excel Solver and a GRG nonlinear method. Depending on whether the spot price was greater or smaller than water value, the optimiser chose to generate at maximum efficiency before increasing to maximum output as spot price rose. The optimisation encountered difficulties when extending the problem to include multiple units. The Excel Solver was unable to find the global optimum without increasing compute times to unacceptable levels. To proceed further with this optimisation problem, it would need to be moved to a platform with more complex solvers.

year: 2022

title: The perfect stroke: Moving beyond the performance narrative within rowing

authors: Green, Toni-Elizabeth

subjects: narrative

abstract: This Thesis presents a narrative inquiry into the experiences rowers have within their sport, through exploring the stories they tell. Following Carless and Douglas (2012) my thesis identifies that success is a multi-dimensional concept. In doing so, I challenge the dominant performance narrative within sport that conceptualises success solely as winning.
The performance narrative is often unsustainable and therefore can be damaging to an athlete’s well-being, due to such circumstances as injury, de-selection, drop out, aging, and losing. This can lead to narrative wreckage; where the individual no longer knows how to make sense of their life as the dominant story they told no longer aligns with their experiences. Highlighting, exploring and sharing stories that resist or move past the performance narrative can give individuals the ability to view themselves as a multi-faceted identity, allowing them to holistically enjoy sporting participation.
Rowers interviewed in this thesis told stories of winning, but also of friendship, loyalty, and the freedom of movement. Of particular interest were the stories told that shared a sense of embodied convergence; the sensation of merging with the medium (Anderson, 2012). As yet, the convergence narrative is largely underdeveloped in the broader sporting literature; thus the paper drew heavily on the literature surrounding surfing in which the notion of convergence has been developed.
By sharing and spreading of a range of different stories, individuals develop their narrative repertoire. This gives them the resources to be able to move past the performance narrative, and restory themselves if, and when, it no longer aligns with their experiences.
My thesis looks to add to the existing literature resisting the performance narrative, by sharing evocative tales showing the complexities and intricacies of resisting or conforming to the performance narrative, and essentially, the joy that can be found within the sport of rowing.

text: The perfect stroke: Moving beyond the performance narrative within rowing This Thesis presents a narrative inquiry into the experiences rowers have within their sport, through exploring the stories they tell. Following Carless and Douglas (2012) my thesis identifies that success is a multi-dimensional concept. In doing so, I challenge the dominant performance narrative within sport that conceptualises success solely as winning.
The performance narrative is often unsustainable and therefore can be damaging to an athlete’s well-being, due to such circumstances as injury, de-selection, drop out, aging, and losing. This can lead to narrative wreckage; where the individual no longer knows how to make sense of their life as the dominant story they told no longer aligns with their experiences. Highlighting, exploring and sharing stories that resist or move past the performance narrative can give individuals the ability to view themselves as a multi-faceted identity, allowing them to holistically enjoy sporting participation.
Rowers interviewed in this thesis told stories of winning, but also of friendship, loyalty, and the freedom of movement. Of particular interest were the stories told that shared a sense of embodied convergence; the sensation of merging with the medium (Anderson, 2012). As yet, the convergence narrative is largely underdeveloped in the broader sporting literature; thus the paper drew heavily on the literature surrounding surfing in which the notion of convergence has been developed.
By sharing and spreading of a range of different stories, individuals develop their narrative repertoire. This gives them the resources to be able to move past the performance narrative, and restory themselves if, and when, it no longer aligns with their experiences.
My thesis looks to add to the existing literature resisting the performance narrative, by sharing evocative tales showing the complexities and intricacies of resisting or conforming to the performance narrative, and essentially, the joy that can be found within the sport of rowing.

year: 2014

title: Problematic reasoning under the guise of anti-Māori talk: A case study of the Three Waters tweets

authors: Tan, Kyle K. H.

abstract: Drawing from a subset of Twitter/X quotes (or tweets) on the politically controversial Three Waters Reform, this study identified forms of anti-Māori discourse through a deductive analysis. A complementary analysis was conducted to unpack how problematic reasoning fueled racism against Māori. Our results revealed distinct and interconnected themes—“resources,” “culture,” “stirrer,” “privilege,” and “one people”—that portrayed Māori as undeserving, lacking expertise, threatening, and unworthy of equitable treatment, as New Zealand citizens are entitled to enjoy liberal democratic values. Anti-Māori speakers employed problematic reasoning tactics to obstruct the public from understanding the truth or to encourage others to form ill-informed opinions through emotions, supposed authority, and conspiracy. Exemplar tweets were provided to illustrate the myriad instances of false information related to patterns of anti-Māori discourse. Evidence from this study makes the case for addressing racism on social media and creating interventions to expand media literacy amongst the public to discern problematic reasonings.

text: Problematic reasoning under the guise of anti-Māori talk: A case study of the Three Waters tweets Drawing from a subset of Twitter/X quotes (or tweets) on the politically controversial Three Waters Reform, this study identified forms of anti-Māori discourse through a deductive analysis. A complementary analysis was conducted to unpack how problematic reasoning fueled racism against Māori. Our results revealed distinct and interconnected themes—“resources,” “culture,” “stirrer,” “privilege,” and “one people”—that portrayed Māori as undeserving, lacking expertise, threatening, and unworthy of equitable treatment, as New Zealand citizens are entitled to enjoy liberal democratic values. Anti-Māori speakers employed problematic reasoning tactics to obstruct the public from understanding the truth or to encourage others to form ill-informed opinions through emotions, supposed authority, and conspiracy. Exemplar tweets were provided to illustrate the myriad instances of false information related to patterns of anti-Māori discourse. Evidence from this study makes the case for addressing racism on social media and creating interventions to expand media literacy amongst the public to discern problematic reasonings.

year: 2025