A pilot plan to establish back-up batteries across Canberra government-owned properties will begin at the end of next month, with tenders called for installations across 14 of the most appropriate sites.
Two tenders were released on Thursday, one to supply the construction machinery and "power generation and distribution machinery" for four batteries of up to 450 kilowatt hours (kWh) storage and another to supply 10 smaller sites, each of less than 60 kWh storage.
The 450 kWh battery tender requires suppliers to design and install systems which would best suit a school or a similar-sized site which already has a rooftop solar array. The tender also calls for one of these sites to be supplemented by a solar array.
The 10 smaller 60kWh battery systems are targeted at depots, such as those operated by City Services.
The ACT government has around 280 sites and those selected, chosen through internal modelling, will be disclosed publicly closer to the release of the full tender documents.
The government has broadly developed its rollout program for back-up battery power storage along three so-called "streams", all contributing toward the plan to supply the territory with 100 per cent renewable energy on a sustainable basis.
Stream one is the most significant project: a grid-scale "big battery" of 250 megawatts, roughly spanning the size of a hectare and generating sufficient storage to supply power for roughly a third of Canberra households during peak periods.
A request for proposals on this project will be rolled out toward the end of the year, with French renewables and battery storage developer Neoen certain to be an aggressive bidder.
Neoen won a 14-year deal with the ACT government to annually supply 100 megawatts of wind-generated energy and is currently constructing a 100 megawatt battery adjacent to the Queanbeyan substation. It also won the recent contract to build a 450 megawatt lithium-ion battery in Geelong.
Stream two is to aimed at harnessing existing solar arrays installed across government properties, while providing back-up for smaller sites. This pilot program may also dovetail with the intention to lease 90 electric buses for the ACTION fleet.
In June last year, 42 suppliers had expressed interest in participating in stream two.
Stream three will be the so-called "community batteries" project, which potentially will place storage batteries in places such as parks and suburban land. Details of how this part of the renewables project will operate are still being developed.
The role of the various streams is to operate within what the renewable energy boffins describe as an "ecosystem" of power storage.
This would increase local network reliability by reducing pressure and congestion on the grid, while managing the amount of power flowing back into the grid due to the huge uptake in rooftop solar across the ACT in the past seven years.
Power generated by these systems during the day can be held by batteries and discharged during peak periods, which is generally between 6pm to 8pm each day.
Too much "residential" power being fed back into the grid causes instability and thermal issues, and batteries are useful in managing that instability.
Solar generation in the ACT, according to the government's latest feed-in tariff report, totalled 141,411 megawatt hours in 2020-21, an annual increase of 34.8 per cent. There are now around 35,000 small and medium size solar generators in the territory.
Large scale batteries provide not just energy storage, but protection against grid frequency deviation. This protection role is also a lucrative profit centre for companies such as Neoen.
