Plans for Pleystowe battery storage lodged to Mackay council

A new big battery build proposed for a privately-owned cane farm west of Mackay could power up to 30,000 homes each day and cut electricity prices. See the plans.

Developers have lodged plans to build a Battery Energy Storage System at Pleystowe, west of Mackay. Picture: Documents submitted to Mackay Regional Council

A new Battery Energy Storage System proposed for privately-owned cane farm west of Mackay could power up to 30,000 homes each day and cut electricity prices.

RPS, on behalf of Edity Energy, has lodged plans to Mackay Regional Council to build the battery system on a 44ha property at Pleystowe which it says is strategically positioned opposite the Pioneer Valley substation.

If approved, it would take up 5ha — just over 10 per cent of the farm — and be capable of storing 200MW or 800MWh, enough to power about 30,000 four-person households for 24 hours.

The application explains the project could prevent the Australian Energy Market Operator from resorting to using “switch-off mechanisms” to manage the electricity network as more Mackay consumers install rooftop solar systems and electricity usage changes.

Documents state a third of Mackay’s 55,377 dwellings have rooftop solar, with this number only expected to climb.

They state the AEMO cannot control or schedule the 139.36MW of “behind-the-meter” electricity those rooftops produce, resulting in an oversupply of power to the grid during the day and an undersupply in the evenings when demand was at its peak.

Mackay at risk of unstable power grid

Documents state the region’s power network — already complicated by “constrained distribution lines” — was vulnerable to voltage instability as electricity usage in the evenings continued to climb alongside solar installs.

The proposed battery system would “absorb” excess power from the grid during the day via underground cables connected to the substation.

Then it releases it back during peak periods or “whenever power fluctuations occur”.

RPS stated the batteries would help balance the grid, lower peak-pricing for Ergon and Powerlink customers, and support the nation’s transition to renewable energy which required reducing our reliance on coal and gas-fired power stations.

Battery systems support power grid ‘faster’ than pumped hydro

It further states battery systems were “unique” with their “instantaneous control function” that could provide support to the network at “sub-second intervals” and “faster than long-duration storage solutions” like pumped hydro.

Positioning a battery system at Pleystowe allows the control of energy flowing into and out of the Central and North Queensland Renewable Energy Zones.

Developers have lodged plans to build a Battery Energy Storage System at Pleystowe, west of Mackay. Picture: Documents submitted to Mackay Regional Council

These zones, being a recent initiative of the state government to coordinate the rollout of its clean energy plan, connect to “various thermal and renewable energy generators” and distribute power to areas like Collinsville, Hay Point and Nebo.

Documents detail the hermetically-sealed lithium-ion cell batteries at Pleystowe would be encased in cabinets up to 3m high on a concrete slab, with the facility boasting an operational lifespan of about 50 years.

“The repowering of the site will occur around the 21-25 year mark,” they state.

“At the conclusion of the project’s operational life, the BESS facility will be decommissioned with the land returned to its original agricultural state to allow the continuation of cropping activities.”

How developer intends to manage ‘credible’ risk of fire

Documents state there is a “credible” risk of the batteries catching on fire because of “thermal runaway” - a situation where heat cannot escape from the cell or battery and temperatures rise uncontrollably.

Proposed control measures include using heat radiation modelling to determine minimum distances between batteries, installing a battery monitoring and gas detection system, ensuring adequate ventilation, and in the event of “uncontrolled” thermal runaway, “the provision for complete flooding” of the units.

Ventilation is also listed as a measure alongside exhaust systems to minimise explosion risks.

Documents state the configuration of the battery systems will be known once the project reaches the detailed design phase with the developer to then submit a Risk Management Plan to the council as a condition of approval.