The economics of transmission constraints on wind farms: some evidence from South Australia

The impacts of transmission congestion and network investment on the development of the Australian wind energy industry have received growing attention from wind farm developers as well as relevant policy stakeholders such as the Australian Energy Market Commission (AEMC). There are many potential wind farm sites across the country with excellent wind regimes yet only limited transmission capacity. At least one wind farm in South Australia has spent a period following construction where its output was curtailed by transmission constraints (NEMMCO, 2009). Current market rules do not guarantee dispatch to an existing wind farm as more wind generation connects to the same transmission. Given the expense of transmission network extension and augmentation, there are interesting questions of what economic impacts such constraints might have for wind farm operators. This paper examines this issue in the context of the South Australian region of the Australian National Electricity Market (NEM). The State currently hosts almost half of total Australian wind generation capacity and has significant transmission capacity limitations for further development. Half hour wholesale electricity spot prices were used along with generation data from nine South Australian wind farms over the 2008-9 and 2009-10 financial years to assess the potential impact that transmission constraints might have had on wind farm revenue. Results showed that a number of the wind farms would have suffered only very limited revenue reductions from having significantly greater wind farm capacity than the rating of their transmission connection to the NEM. Importantly, some wind farms could be limited to a maximum power output of half their rated capacity and still achieve higher capacity factors then other already existing unconstrained wind farms. The key reasons for this are that wind farms do not generate at rated capacity for a great deal of the time over the year, periods of high wind generation appear to be associated with lower wholesale prices and there is significant variance between the wind farms capacity factors. Our findings suggest that there may be circumstances where wind farm developers might benefit from installing more wind turbines than the capacity of their transmission connection.Integration, market price, NEM, South Australia, Wind, Environmental Economics and Policy, Farm Management, Resource /Energy Economics and Policy,

Renewable energy integration into the Australian National Electricity Market: Characterising the energy value of wind and solar generation

This paper examines how key characteristics of the underlying wind and solar resources may impact on their energy value within the Australian National Electricity Market(NEM). Analysis has been performed for wind generation using half hour NEM data for South Australia over the 2008-9 financial year. The potential integration of large scale solar generation has been modelled using direct normal solar radiant energy measurements from the Bureau of Meteorology for six sites across the NEM. For wind energy, the level and variability of actual wind farm outputs in South Australia is analysed. High levels of wind generation in that State have been found to have a strong secondary effect on spot prices. Wind generation's low operating costs will see it displacing higher operating cost fossil-fuel plant at times of high wind. At the same time, the increased variability of wind may impose additional challenges and costs on conventional plant which will also be reflected in wholesale spot market prices. It is shown that this is proving particularly important during high wind penetration periods, which are contributing to an increased frequency of low or even negative prices. The solar resource in South Australia is shown to be highly variable; however, as seen with wind power, geographical dispersion of generators can significantly reduce power variability, even with as few as six sites. The correlation of the solar resource with spot prices also appears to be superior to wind generation. Modelling using the Adelaide solar resource showed that, for electricity sold into the spot market, two-axis tracking solar generators would achieve an average price that is over twice that received by wind generators over the year 2008-9 analysed. Of course, significant solar generation deployment might drive similar price impacts as seen with wind generation, thereby reducing this advantage. Considering the potential implications of both major wind and solar generation within South Australia, the solar and wind resources within the State appear, on average, to be non-correlated for the magnitude, and the change in magnitude, across half an hour. The analysis shows that solar and wind resources within the NEM have key characteristics that can markedly impact on their energy value within the wholesale electricity market. High levels of renewable electricity are already affecting spot prices, highlighting the need for low bidding renewable generators to attain power purchase contracts and for developers to consider this effect when choosing a site location for renewable generators. Other generators within the NEM may also be significantly impacted by major renewable energy deployment. The long-term success of renewable generation will likely depend on maximising the energy value that it contributes to the electricity industry.Energy value, Integration, NEM, Solar, Variability, Wind, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Teens, Video Games, and Civics

Analyzes survey findings on trends in teenagers' video gaming, the social context, the role of parents and monitoring, and the link between specific gaming experiences and civic activities. Explores gaming's potential as civic learning opportunities

Re-writing Recent History: Developing a National Reconciliation Pedagogy Using a Video Game for School Age Children

Australian Aboriginal people have suffered ignominy through British policies and practices since the legal conquest of their land in 1788. They have been historically and socially misrepresented on the premise of their race alone. Recent attempts at reconciliation have come some way towards a shared culture. However, the national curriculum has not been effective in promoting reconciliation as an important part of a student's education. As a pedagogical tool for advancing notions of reconciliation a game was developed. The goal of the game is for students to experience notions of trust, empathy and collaboration - core to notions of reconciliation. Initial evaluation of the game suggests these goals are being met

Radio Controlled Aircraft

Building an R/C aircraft isn’t exactly a project intent on breaking ground in the field of aerospace engineering, rather it is an opportunity to apply fluid dynamics in a practical manner to gain experience in aeronautical engineering. An aerospace engineer is one who designs and builds aircraft and spacecraft and are often tasked with deeming an aircraft flight worthy or not. We will attempt to predict the feasibility of our custom plane designs using aircraft engineering techniques found through research and through texts provided by our advisor, Dr. Jayasimha. The goal of this design is to design and fabricate a plane that abides by the SAE 2012 Aircraft Competition guidelines. These constraints require the plane to lift off in under 200 ft of runway, not have rotary wings (such as helicopter), weigh less than 55 lbs, and the propeller must rotate at the same RPM as the motor. The problem we are trying to solve is to accurately predict the behavior of the model prior to fabrication by using aerodynamic engineering calculations and simplifications. We aim to predict the take-off velocity, the induced drags on the plane, required engine performance, in-flight performance, and overall feasibility of the design. If successful, we will gain a decent understanding of how aerospace engineers predict the flight behavior and specification requirements of airplanes. It is actually more difficult to design a flightworthy small-scale aircraft rather than a large commercial one due to the low altitude of operation, which induces fairly laminar boundary conditions, which in turn increases the drag force on the plane. In order to do this, coefficients of lift and drag of the airplane’s airfoil will be found using the software XFLYER 5, which is a specialized program for aircraft design. Using this software and formulae found from R/C aircraft related texts, an excel sheet will be made to predict flight performance and by altering the dimensions of the plane and airfoil shape, we will be able to choose the most flightworthy design. So far we are working with an airfoil at an angle of attack of 7 degrees which yields a coefficient of lift of 0.943 and a coefficient of drag of 0.0062. With rectangular wings 13’’X 42’’, a fuselage of length 5.5 ft, a Rimfire 1.60 motor, and a weight of 25 lbs, it was predicted that the plane will need to reach 37mph, overcome a drag of 14.5 Newtons, and will take about 77 ft of runway to lift off. We aim to reduce these values by adjusting parameters accordingly.https://scholarscompass.vcu.edu/capstone/1053/thumbnail.jp

Teens and social media

Content creation by teenagers continues to grow, with 64% of online teenagers ages 12 to 17 engaging in at least one type of content creation, up from 57% of online teens in 2004. The use of social media is gaining a greater foothold in teen life as they embrace the conversational nature of interactive online media. Girls continue to dominate most elements of content creation. Some 35% of all teen girls blog, compared with 20% of online boys, and 54% of wired girls post photos online compared with 40% of online boys. Boys, however, do dominate one area - posting of video content online. Online teen boys are nearly twice as likely as online girls (19% vs. 10%) to have posted a video online somewhere where someone else could see it

Correlation Analysis of Roadway Light Levels, Hard Braking, and Crashes

This study analyzed three primary datasets to investigate the correlation between street lighting illuminance, vehicle braking behavior, and crashes on urban and suburban roadways in Washoe County, Nevada. The first dataset, Street Lighting Illuminance Data, collected from March through December 2020, provides comprehensive illumination data for all urban and suburban roads within Washoe County which mainly consisted of the Reno and Sparks Truckee Meadows area. The second dataset, Washoe County, Nevada, urban and suburban Wejo Speed Connected Vehicle Dataset, collected from March 1 through March 16, 2021, provides detailed vehicle trajectory information, from which acceleration and deceleration data were extracted using a Python script. Positive values indicated acceleration, while negative values denoted deceleration. The third dataset, Washoe County, Nevada, urban and suburban traffic crash dataset, collected from the Nevada Crash Reporting System for years 2013-2017, provides detailed vehicle crash information for the same study area. A sequential methodology was employed to overlay the illumination levels with the deceleration and vehicle crash data. This involved defining a 100-foot, 300-foot, and 500-foot diameter buffer at the center of intersections and a 120-foot perpendicular buffer from the centerline of the roadway segment, along the 1/4-mile long roadway segments within the study area, where illumination, deceleration, and crash data were analyzed concurrently. The study further refined its analysis by employing Geographic Information System (GIS) techniques for visualizing the relationship between ambient illumination levels and hard braking events. This visualization facilitated an initial understanding of the potential correlation between the two variables. Subsequently, a coefficient to quantify the relationships. The study findings suggest a moderate to strong positive correlation between average illumination and nighttime crashes at both intersections and roadway segments. The findings also suggest a negligible to weak positive correlation between average illumination and hard braking events at intersections and roadway segments. This insight can be important for urban planning and traffic safety studies. One of the three main contributions of this study lies in its establishment of criteria for evaluating hard braking through the analysis of multi-second vehicle trajectory data. This new criteria does not contradict already established definitions for hard braking but instead complements these definitions by allowing multi-second data to more easily be evaluated and included in the research. Additionally, another main contribution of this study is the correlation analysis between the three datasets- lighting, hard braking events, and vehicle crashes. The last main contribution of this study is identifying that there is a negligible to weak positive correlation between average illumination levels and hard braking events. Such findings are significant for the formulation of traffic safety initiatives and the improvement of urban road lighting policies. By analyzing the relationships between roadway illumination, hard braking, and crashes, this research offers critical insights that can inform the development of targeted improvements aimed at enhancing traffic safety and urban driving conditions

Identifying the underlying structure and dynamic interactions in a voting network

We analyse the structure and behaviour of a specific voting network using a dynamic structure-based methodology which draws on Q-Analysis and social network theory. Our empirical focus is on the Eurovision Song Contest over a period of 20 years. For a multicultural contest of this kind, one of the key questions is how the quality of a song is judged and how voting groups emerge. We investigate structures that may identify the winner based purely on the topology of the network. This provides a basic framework to identify what the characteristics associated with becoming a winner are, and may help to establish a homogenous criterion for subjective measures such as quality. Further, we measure the importance of voting cliques, and present a dynamic model based on a changing multidimensional measure of connectivity in order to reveal the formation of emerging community structure within the contest. Finally, we study the dynamic behaviour exhibited by the network in order to understand the clustering of voting preferences and the relationship between local and global properties.Comment: 20 pages, 10 figures, 3 tables, submitted to Physica