...but doesn't state what costs are associated with those varying durations.
This is a basic numeracy/literacy issue. I'm super bullish on solar and storage and follow this issue in the news, which is why it's so frustrating when these things aren't clearly communicated...
Even that would be impressive. But it's just not clear that that is what the data says. 4 hours of storage, if the storage is expected to cycle twice per day (once in the morning, when sunlight is still dim but demand has picked up, using fossil/nuclear/geothermal/wind energy generated at night when demand is super low, and once in the evening as sun sets but demand still high, using solar energy generated during the day), then that is a factor of 2 better for costs than if storage is expected to only cycle once a day or worse.
But we can't tell because the article doesn't mention any of these details. This factor of two (or more) is the difference between status quo and a revolution, but the article remains unclear.
> The reality is that the grid needs to work when there is no sun or wind for days or even weeks.
Renewables do not need to provide that capability today or tomorrow. Renewable penetration will take a few decades to reach that level where we have to worry about that and by that point storage will hopefully be up to the task. Right now just a few hours of storage is already enough to shave some peak demand off fossil fuel plants.
