Some news on the SA grid battery system: Brian Perusse from AES Energy Storage states that
“Industry officials estimated 100 MWh of battery capacity could be supplied for $700 to $1,000 per kilowatt hour.”
Compare that to the cost of building AGL’s massive industrial Dalton gas-fired power plant: the original estimate 7 years ago was $1.5 billion for a 1,500 MW plant. Doing the math, that is about $1000 per kilowatt capacity at a 7-year-old rate. Add to that an annual inflation rate of 2.2% over the last 7 years, and the cost per kilowatt is approx $1150.
The clear choice is the grid-scale battery – even if you don’t factor in the running costs of gas.