The technology is already available for generating reliable continuous electrical power from some renewables (eg. biomass). However, the current power capacity is small. Further development in the renewables sector is required before any significant level of substitution of coal-fired power can take place. Research and development into solar thermal, photovoltaic, ocean and geothermal energy indicates very promising prospects for reliable and continuous power from renewables within the next two to four decades.
A key to supplanting coal and gas-powered generation will be the development of storage media able to capture intermittent energy and supply controlled output to match demand. Promising technologies are at the demonstration level. The more decentralised distribution of renewable resources compared to fossil fuels will require reconfiguration of the national electricity grid to better integrate power inputs from more variable input sources and reduce transmission losses from the more remote renewable sites, especially geothermal.
Overall, the cost of electricity from renewables is significantly higher than for coal and gas. However this differential disappears when the costs of carbon capture and sequestration are included in the price of coal and gas-based generation.
Provided a suitable policy framework is in place, there appears to be no technical or financial impediment to renewables providing about 50 per cent of all Australian electricity demand by 2040. In the longer term, current research and development suggests that a low-carbon electricity sector is attainable with total substitution of coal, with gas filling the role of change agent.