The Australian continent experiences a collection of unique conditions which, when combined, create the unique environment in which the Australian electricity network operates. The network configuration inis different from that of the rest of the world. For example, the National Electricity Market (NEM) covers the entire east coast. Compared to areas in other countries where various studies have been carried out, this is far larger and has a greater diversity in generation across the network. Successfully integrating high penetration solar power into the Australian electricity network is highly dependent on mitigating the effects of intermittency. Some initial investigations have been carried out in other countries, but they were of limited scope and are not necessarily applicable in the Australian context. Various articles in the existing literature discuss the work required to facilitate the integration of high penetration intermittent generation. The recommended work required includes:
- development of models representing solar behaviour and net load
- determination of required flexibility of non-variable generation to manage the variability introduced by high penetration intermittent generation
- simulations to determine the impact of high penetration intermittent generation on power quality at the distribution level
- investigations into how flexibility can be introduced (or variability mitigated) into electrical networks through the utilisation of and load participation.
For successful integration of high penetration intermittent generation into the Australian electricity network, it is necessary for this work to be performed within an Australian context. An example would be to determine the extent of flexibility required in the Australian electricity network. This would call for studies to be performed that consider Australia’s generation mix and the individual capabilities of all conventional generators. In the NEM, generators are scheduled and dispatched into production to match supply every five minutes. NEMwould need to work out how much generation flexibility is needed to manage the expected increase in variability from the introduction of intermittent renewable generation. In the case of the NEM, the extent of variability in net load the network might experience in a five-minute interval needs to be determined.
It was mentioned earlier in the report that accurate forecasting is an essential element for the successful integration of large amounts of intermittent solar generation and for solar power to be economically viable. The Australian Energy Market Operator (AEMO) uses the Australian Wind Energy Forecasting System (AWEFS) which provides a wind forecast every five minutes. There is however no equivalent resource for solar yet. To develop an adequate solar model, it may be necessary to begin accruing irradiance data at existing and proposed sites at five-minute intervals and combine this with historical satellite data.
To facilitate high penetration levels and gain confidence in managing increasing solar penetration levels in Australia, demonstration projects at the distribution level are a necessary preparation, and need to occur locally. The NEM, for example, is exceptionally sparse by international standards, leading to higher characteristic impedances and consequently greater sensitivity to the behaviour of localised load and generation. High penetration of solar power in such networks with high impedance feeders is likely to cause voltage fluctuations beyond acceptable limits due to intermittent solar power output caused by passing clouds. Similar studies to those carried out in other parts of the world need to be performed in Australian locations which have high impedance feeders to investigate the impacts of high penetration solar on such networks.