• The 129MW/h battery bank installed by Tesla at the Hornsdale’s wind farm is proving to be a hit.
• The service is both rapid and precise in stabilising the grid.
• The delivery is better than a synchronous generation unit from coal or gas
• Value add is also revealed in Frequency Control Ancillary Services
• Could this be the answer to grid instability in Africa?

The Australian Energy Market Operator (AEMO) is pleased with the large 129MW/h battery bank installed by Teslanext to the Hornsdale’s wind farm. The utility-scale battery bank was installed within 100-day deadline by the Tesla team. A performance reporton the system was released recently which confirmed utility scale battery banks have a rightful place in any renewable energy production mix.

The report reveals that in the case where there is a spike in demand for electricity from the grid, the battery bank performs better than conventional synchronous generation from coal or gas by providing a rapid and precise response. There is a lag with coal and gas synchronous generation as the system needs time to ramp up.Tesla’s installation can rapidly discharge 100MW for about 75 minutes. It is also assisted by the wind farm production through delivery synchronisation.

AEMO has boxed clever by using the battery banks to provide incremental “Frequency Control Ancillary Services,” which add small amounts of power to the grid to make sure frequency stays right around 50Hz on average. It is important it is to make sure grid frequency is maintained at its pre-determined average, even if the deviations from average haven’t been enough to cause blackouts. It also saves money for the operator. AEMO will ordinarily have to pay extra for additional Frequency Control Ancillary Services to maintain the preferred average frequency.

This added value was not included in the original financial modeling carried out by AEMO when procuring the system. Their report states that “Market arrangements could also be modified to specifically recognize the rapid and accurate response capabilities of batteries, and therefore enhance their ability to earn income from providing them.”

The battery bank has not been fully tested in the event of a power outage or to rapidly rescue grid frequency from falling beneath 49Hz (a situation that would cause an outage). The idea is to prevent such a scenario and the 129MW/h battery bank appears to be doing just that. The unforeseen savings on frequency control is an added bonus.

Author: Bryan Groenendaal  greenbuildingafrica.co.za

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