The conversation between human and AI assistant.
[|Human|] Given these paragraphs about battery storage power stations, for how long battery power storage was cheaper than open cycle gas turbine power as of 2019?
[|AI|] As of 2019, battery power storage is cheaper than open cycle gas turbine power for use up to two hours.
[|Human|] 
Given these paragraphs about battery storage power stations, for how long battery power storage was cheaper than open cycle gas turbine power as of 2019?