Australian Energy Market Operator likes its new Tesla battery quite a bit
Ars Technica 2018-04-11

Enlarge / ADELAIDE, AUSTRALIA - SEPTEMBER 29: Tesla Powerpack batteries during Tesla Powerpack Launch Event at Hornsdale Wind Farm on September 29, 2017 in Adelaide, Australia. (Photo by Mark Brake/Getty Images) (credit: Getty Images)
Last week, the Australian Energy Market Operator (AEMO) released an initial report (PDF) on the performance of the 129MWh Hornsdale battery system that was installed by Tesla last November. It seems the market operator is pleased with the new battery, writing that the service provided by the battery system "is both rapid and precise, compared to the service typically provided by a conventional synchronous generation unit."
A conventional synchronous generation unit refers to a spinning generator, like a coal or a natural gas plant. If there's excess demand for electricity, sometimes these generators can increase their output if there's some headroom, or grid managers can bring so-called "peaker plants" online to help meet peak demand.
But often these units need a little bit of time to start spinning at the appropriate rate. Batteries, on the other hand, have the advantage that they can start putting power on the grid right away; no need to wait for ramping up. Tesla's installation in particular can rapidly discharge 100MW for about 75 minutes. It's also charged by the wind farm that's right next door.