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,

Modern conception of encephalitis lethargica

1. Encephalitis lethargica is an epidemic disease of the central nervous system quite distinct from similar affections such as acute poliomyelitis and cerebro-spinal fever. 2. Since its first appearance there has been a rapid increase in the number of cases, and this increase still continues. 3. The causal organism has not yet been isolated but it is of the nature of a filterable virus. 4. Many cases are very gradual in onset and of a chronic nature throughout, and in these the acute stage is either absent or is so mild as to pass unnoticed even by the patient. 5. There has been a very marked change in type, the initial "negative" phase in which lethargy and palsies predominated being replaced by a "positive" phase with insomnia and involuntary movements as prominent symptoms and lethargy slight or absent. 6. The symptoms vary widely in different cases and many are liable to be missed unless a careful lookout is kept for the disease. 7. No drug has yet been discovered which has any permanent effect on the course of the disease. 8. The prognosis of Parkinsonism is very uncertain but it may remain practically stationary for at least seven years. 9. In some cases of Parkinsonism great improvement follows the use of hyoscine or belladonna, but this improvement is only temporary and the drug loses its power after a time

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

Indigenous Students’ Wellbeing and The Mobilisation of Ethics of Care in the Contact Zone

Schools have historically been a location of oppression for Indigenous students in Australian schools. Giroux (1992, p. 24) argues it is critical to create a democratic space inside schools and Aboriginal Community Education Officers (henceforward ACEOs) have been employed to achieve this goal. This paper explores the processes of democratising the school space by ACEOs through an Indigenous ethics of care framework. The enactment of Indigenous ethics of care between ACEOs and Indigenous students will be explored, with a particular focus on the use of the Nunga[1] room (Blanch, 2009, p. 66) as a ‘safe-house’ (Pratt, 1991). Pratt uses the safe house ‘to refer to social and intellectual spaces where groups can constitute themselves as horizontal, homogeneous, sovereign communities with high degrees of trust, shared understandings, temporary protection from legacies of oppression’ (1991, 6). The paucity of Indigenous ethics of care theory and the role of ACEOs’ work in the Nunga room in education literature is problematic, as many non-Indigenous teachers continue to racialise Indigenous students through negative stereotypes. Qualitative data will be used to demonstrate the links between pedagogy, Indigenous ethics of care and the role of ACEOs to illustrate the need for greater recognition of this theoretical paradigm. This is critical information for teachers and pre-service teachers as it expands conceptualisations of social justice and its link to pedagogy. Contact zone theory will be used to explore the tensions of working and learning in schools that are shaped by institutional power relations that routinely lead to the misrecognition of Aboriginal students’ location as First Nations citizens. [1] Nunga is a term used by Aboriginal people in some parts of South Australia to identify as a collective

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

Reliability-cost trade-offs for electricity industry planning with high variable renewable energy penetrations in emerging economies: A case study of Indonesia�s Java-Bali grid

Electricity industries in emerging economies face particular challenges in delivering affordable, environmentally sustainable, and secure power given growing demand and limited financial resources. While supply reliability is often poor and emission reductions given lower priority, solar and wind are now amongst our cheapest supply options but highly variable. Our study seeks to demonstrate the potential value of trading-off reliability standards against higher renewables and lower industry costs in future generation planning. We use an open-source, evolutionary programming-based, capacity expansion planning tool, NEMO, to solve least cost generation mixes for Indonesia�s Java-Bali grid in 2030. We explicitly test the cost and emission impacts of reliability targets of 0.005%�5% unserved energy (USE), modelled as both a hard optimization constraint and a penalty price on USE in the cost function. Our results highlight that lower reliability targets can increase solar and wind penetrations, reducing CO2 emissions while reducing industry costs. Both methods of incorporating reliability delivered similar outcomes but pricing USE had some advantages for optimization over hard constraint setting. While the impacts of lower reliability on consumers requires careful consideration, our study highlights the potential cost and emission implications of arguably unrealistic reliability targets in generation planning for emerging economies

Clustering based assessment of cost, security and environmental tradeoffs with possible future electricity generation portfolios

The electricity sector has a key role to play in the sustainable energy transition. The falling costs of wind and solar PV have added to both the opportunities yet also challenges of balancing sometimes competing industry objectives of costs, security, and environmental impacts. This paper presents novel techniques for assessing possible future industry generation portfolios in three ways: (1) incorporating explicit metrics for energy trilemma objectives into modelling, (2) using the optimization process of evolutionary programming to map the solution space of �high performing�, near least-cost, portfolio solutions, and (3) applying boundary min�max cases and clustering to categorize these varied portfolios to better facilitate planning and policy making. We use an open-source evolutionary programming tool, National Electricity Market Optimiser, to assess possible future generation portfolios for Indonesia�s Java-Bali interconnected power system. Our findings highlight the wide range of possible portfolios that might potentially deliver similar total industry costs, and their different security and environmental implications. In particular, additional solar photovoltaic deployment appears a low-risk opportunity to reduce costs and emissions compared to more fossil-fuel oriented mixes. Our novel techniques may be useful for the energy modelling community seeking to better understand and communicate complex, uncertain, and multi-dimensional choices for electricity industry planning