Ergon Energy (Australia)

As the Australian energy sector progresses toward its 2050 net-zero emissions target, Power Purchase Agreements (PPAs) have become a key instrument for providing price certainty in renewable energy investments. However, the financial viability of these contractual agreements under current market price volatility remains insufficiently examined. This study addresses this gap by quantitatively modelling PPA prices and settlement values for solar, wind, and coal technologies over the period 2022-2024, using both fixed and fixed-CPI indexed pricing schemes within the Queensland Electricity Market. A Net Present Value (NPV)-based approach, identified through the literature review, was employed to calculate break-even PPA prices by incorporating capital expenditure, operational costs, and mismatch costs. The results indicate that shorter contract durations significantly increase PPA prices and Levelized Cost of Energy (LCOE), particularly for capital-intensive technologies such as coal. The annual PPA settlement analysis further reveals that while solar and wind projects consistently experience negative settlements, coal projects are more likely to achieve positive settlements under conditions of suppressed spot market electricity prices. These findings highlight that conventional PPA structures may inadequately protect buyers in high-renewable electricity markets. The study concludes by emphasising the need for dynamic PPA pricing models and hybrid financial instruments to enable more effective risk-sharing between buyers and sellers, thereby supporting long-term financial sustainability.

The life of cellulosic insulation is often described as the life of a transformer. Monitoring systems and procedures are designed to maximize the life of the cellulose and hence, the life of the transformer. Many laboratory tests have shown that cellulose degrades at a lower rate in ester-based insulating liquids than in mineral oils. One proposed theory for the enhanced stability is the transesterification reaction in which the carboxylic acid portion of the ester is hydrolyzed from the ester insulating liquid and reacted with the hydroxyl group on the cellulose. The long chain hydrocarbon group provides a hydrophobic barrier preventing water from hydrolyzing the cellulose. The transesterification reaction, and the evidence for it, will be discussed.

The transition to hydrogen as a primary fuel in aviation requires innovative strategies to mitigate challenges associated with flashback in combustion systems. Due to its low volumetric energy density, hydrogen is preferably stored at cryogenic temperatures (T ≤ 100 K). Since stoichiometric hydrogen/air laminar premixed flames have been observed to sustain combustion even at temperatures as low as 100 K, low-temperature injection can be used as a strategy to control flashback and stabilize the flame. This study investigates the performance of low-temperature rich premixed hydrogen/air combustion within a model Rich-Quench-Lean (RQL) combustor configuration equipped with a Trapped Vortex Cavity (TVC). Large Eddy Simulations (LES) with Eulerian Stochastic Field (ESF) approach are conducted for this purpose. The LES are first validated against a recent experimental campaign involving high-speed chemiluminescence diagnostics. Subsequently, parametric studies explore the operating limits and flashback resistance of rich hydrogen flames under varying low-temperature conditions. Results indicate a strong sensitivity of the flame position within the TVC to the injection temperature. The strong reduction in laminar flame speed observed in experiments, however, is counteracted by the increase in turbulent/laminar flame speed ratio, adding to the complexity of the problem. Insights on how to control the flame dynamics in the cavity are provided within this study with the purpose of optimizing RQL-TVC designs for robust, low-emission, and flashback-resistant operation in hydrogen-based propulsion systems.

The article is devoted to the numerical calculation of the cylindrical part a tank car boiler, which is represented as a single-layer shell, and the study of its stress-strain state using the provisions of the semi-momentum theory shells. In some cases, under actual operating conditions of a tank car boiler, when the base metal wears out under the influence of corrosive phenomena arising from the interaction an aggressive environment and a storage and transportation tank, it becomes necessary to assess the stress-strain state and search for the most dangerous areas. The authors of this article propose a calculation algorithm that allows determining the stress state cylindrical shell of a structure, taking into account the decrease in metal thickness when corrosion occurs, using the method of calculated sections in the MathCAD software environment. The constructed mathematical model makes it possible to determine: the values of longitudinal and transverse displacements a flexible homogeneous shell of constant stiffness under the acting combined load; the values of normal forces, bending moments, and equivalent stresses in accordance with the adopted design scheme of the cylindrical part the boiler. The simplicity of implementing the proposed numerical algorithm makes it possible to use it in engineering practice, for example, during technical inspections and making decisions on the further safe operation tank car boilers according to the adjusted methodology at the early stages of research

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die mich mit ihren fachlichen Reviews schon von Anfang an unterstützt haben. Cla Gleiser und Tina Nart verdanke ich die sprachliche Korrektur meiner Texte. Die veranschaulichenden Abbildungen stammen von Fabian Elsener. Schließlich danke ich dem Verlag De Gruyter für die Veröffentlichung meines Buchs.

Abstract The increased use of, and reliance upon, technology and digitalisation, especially in the galleries, libraries, archives and museums [GLAM] sector, has motivated innovative approaches to the curation of cultural material. These changes are especially evident when collaborating with Indigenous partners. Indigenous Data Governance [IDG] and Indigenous Data Sovereignty [IDS], with an emphasis on self-determination of Indigenous peoples, have called for an emerging focus on ethical and culturally sensitive approaches to data collection and management across a range of disciplines and sectors. This chapter reports on broader discussions, specifically with mid-North South Australia, Indigenous community members around the appropriate and ethical collection, representation and curation of cultural material on Country applying digital formats. It investigates ways to create a ‘future identity’ through built form as well as providing a ‘safe’ place for preservation of their oral histories. It highlights the many questions raised around the ethically and culturally sensitive aspects of the collection, curation and archiving of Indigenous cultural material. It documents the preliminary outcomes of these conversations in the context of current research on IDS best practices in the field. The non-Aboriginal authors acknowledge our supporting position in the realisation of effective IDS and self-determination of our Aboriginal partners.

Abstract This chapter briefly describes how transformer and shunt reactor sound can be characterized for specification and measurement purposes. This chapter then describes how transformer and shunt reactor sound levels can be controlled by design or other external measures. Finally, this chapter describes typical sound levels for transformers and shunt reactors for specification purposes.

Abstract This chapter describes how to specify requirements for components and fittings used on power transformers and reactors. It includes material on coolers, terminations, current transformers, tap-changers, internal surge arrestors, other fittings, and control cabinets. It places special emphasis on clear identification and communication of user purchaser expectations and requirements.