The following article appeared in the most recent edition of the Choose Cradle Coast newsletter:

The Clean Energy Council recently released a paper ‘Battery Storage: The New, Clean Peaker’. The report undertakes a financial analysis of modern large-scale batteries and finds that up to a duration of around four hours, large batteries are able to replace the functions and would already be cheaper than constructing new gas peaking plants.

Gas-fired peaking plants in other states are usually started up each afternoon for a few hours, which is when the sun sets and solar generation drops, and when people are getting home and turning on their air conditioners or heaters and other appliances. In Tasmania, we currently do not have a massive amount of solar generation and a larger proportion of our state’s total electricity generation is consumed by large, steady industrial consumers. This means our daily afternoon peak is relatively smaller and can be met without additional short-term generators being started.

Gas-fired peaking plants are the most polluting part of the country’s electricity generation network. Removing these from the network and avoiding the construction of new gas peaking plants, would take a significant quantity of greenhouse gas emissions out of Australia’s energy sector. If batteries can perform this current role instead, this will mean a big win in reducing emissions – even before more coal-fired power stations retire.
Batteries of this size do not yet exist, although plans to build them are underway. Currently, the largest battery in Australia is four to eight times smaller than what would be needed, according to the report, to replace the function of a new 250-megawatt gas peaking plant. The largest battery in the world, the Gateway Storage Project in California, is half to a quarter of the size required to replace a gas peaking plant of that size.

Plans to build larger batteries have been announced in NSW and Victoria, often linked to the planned future retirements of coal-fired power stations. These batteries will go some way towards filling the gaps in generation that retiring coal-fired power stations will leave in the network. However, while these batteries will be able to charge during the day using abundant solar and discharge for a few hours each afternoon, they won’t be able to replace the 24-hour constant generation that coal-fired power stations now produce. Particularly on short cloudy days in winter, there just won’t be enough electricity in the grid to recharge medium (large-scale batteries) and shallow storage (residential-scale batteries). This is where deep storage – large pumped hydro projects such as Lake Cethana and Snowy 2.0, will be crucial to shift energy between days or weeks.

The national electricity network of the future is becoming increasingly complex as more variable generation comes online and the timelines for the retirement of major coal-fired power stations are accelerated. It is going to take a range of storage types to fill all of the gaps including short disruptions, daily peaks and longer drops in variable generation when solar and wind generation isn’t sufficient for extended periods.

Written by Tanya Denison,
Future Energy Facilitator

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Image: Clean Energy Council