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Passey R.,University of New South Wales | Spooner T.,University of New South Wales | MacGill I.,University of New South Wales | Watt M.,IT Power Australia | Syngellakis K.,IT Power Australia
Energy Policy | Year: 2011

Distributed generation is being deployed at increasing levels of penetration on electricity grids worldwide. It can have positive impacts on the network, but also negative impacts if integration is not properly managed. This is especially true of photovoltaics, in part because it's output fluctuates significantly and in part because it is being rapidly deployed in many countries. Potential positive impacts on grid operation can include reduced network flows and hence reduced losses and voltage drops. Potential negative impacts at high penetrations include voltage fluctuations, voltage rise and reverse power flow, power fluctuations, power factor changes, frequency regulation and harmonics, unintentional islanding, fault currents and grounding issues. This paper firstly reviews each of these impacts in detail, along with the current technical approaches available to address them. The second section of this paper discusses key non-technical factors, such as appropriate policies and institutional frameworks, which are essential to effectively coordinate the development and deployment of the different technical solutions most appropriate for particular jurisdictions. These frameworks will be different for different jurisdictions, and so no single approach will be appropriate worldwide. © 2011 Elsevier Ltd.

Dunn R.,Australian National University | Lovegrove K.,IT Power Australia | Burgess G.,Australian National University | Pye J.,Australian National University
Journal of Solar Energy Engineering, Transactions of the ASME | Year: 2012

This paper presents experimental evaluation of ammonia receiver geometries with a 9 m 2 dish concentrator. The experiments involved varying the geometric arrangement of reactor tubes in a thermochemical reactor built from a series of tubes arranged in a conical shape inside a cavity receiver. Differences in conical arrangement were found to affect the efficiency of energy conversion. The solar-to-chemical efficiency gain obtained by varying the receiver geometry was up to 7 absolute. From this, it is apparent that geometric optimizations are worth pursuing since the resulting efficiency gains are achieved with no increase in costs of manufacture for receivers. The experimental results and methodology can be used when developing receivers for larger dish concentrators, such as the second generation 500 m 2 dish concentrator developed at the Australian National University. © 2012 American Society of Mechanical Engineers.

Zapata J.I.,Australian National University | Pye J.,Australian National University | Lovegrove K.,IT Power Australia
Solar Energy | Year: 2013

This paper presents a dynamic model of a once-through-to-superheat solar steam receiver for electricity generation. The receiver is a mono-tube cavity boiler mounted at the focal point of a 500m2 paraboloidal dish concentrator at the Australian National University. The dynamic model is derived from physical principles of mass and energy conservation, and uses a moving boundary formulation, coupled with a switching approach, to represent outlet flow, ranging from sub-cooled liquid to superheated steam. A method to compute outlet mass flow rate for all three receiver outlet flow conditions is included. This modelling approach results in a compact state-space representation of the receiver which is useful in the development of model-based control strategies for the operation of the receiver in a concentrator plant. The model is implemented in TRNSYS 16 and validated with experimental data from the Australian National University 500m2 dish system. © 2013 Elsevier Ltd.

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