The costs of utility scale battery storage in the United States...

The costs of utility scale battery storage in the United States fell about 70% between 2015 and 2018, according to data compiled by the Energy Information Administration (EIA), a part of the Department of Energy.
The average energy capacity cost of utility-scale battery storage went from $2,152 per kilowatt hour (kWh) in 2015 to $625/kWh in 2018, according to the EIA. The agency noted, however, that costs vary widely by region and by application.

My guess on 1.8GWh annual capacity:
- Annual revenue would be around US$360m
- Net profit margin ~20% (cheap cost, it might be higher profit margin)
- Annual net profit ~US$72m
MNS: 63% ownership
MNS attributable net profit: ~A$59m p.a

All imo, just for entertainment.