The main problem with replacing a fossil fuel plant with renewable + batteries is finding a battery system that can hold energy over a sufficiently long period of time and has enough capacity to replace solar/wind when it is dark and calm.
In the studies I've seen the time shift required is on the order of seasons and the capacity required is cost prohibitive.
It may be that the weather patterns in Hawaii are sufficiently stable that it makes it possible to remove the companion base load generation capacity. The article seems to hint at the fact that the total capacity of the coal plant was much higher than the storage capacity of the battery system:
> With 565 megawatt-hours of storage, the battery can’t directly replace the coal plant’s energy production ...
So it isn't clear how much capacity has been lost in this switch. They may also be other changes in the generation portfolio that aren't discussed in the article.
In the studies I've seen the time shift required is on the order of seasons and the capacity required is cost prohibitive.
It may be that the weather patterns in Hawaii are sufficiently stable that it makes it possible to remove the companion base load generation capacity. The article seems to hint at the fact that the total capacity of the coal plant was much higher than the storage capacity of the battery system:
> With 565 megawatt-hours of storage, the battery can’t directly replace the coal plant’s energy production ...
So it isn't clear how much capacity has been lost in this switch. They may also be other changes in the generation portfolio that aren't discussed in the article.