"And that means fewer batteries can keep gas backup under 5%."
What it means is you need the same backup, the same batteries and gas generation, just that it will be used less often.
The goal in generation is to have generation assets generate (and sell) as much power as possible - that lowers unit prices. You can have two, identical, gas turbines. One provides peak power, and one provides baseload. And they will produce power at wildly different costs, because each last 30 years, and the cost is dependent of the number of hours they run each year. The baseload power plant is cheaper just because it runs more.
Wind and solar only need to be out of sync a few days a year. Maybe a week. And you are right back where you started.
"And that means fewer batteries can keep gas backup under 5%."
What it means is you need the same backup, the same batteries and gas generation, just that it will be used less often.
The goal in generation is to have generation assets generate (and sell) as much power as possible - that lowers unit prices. You can have two, identical, gas turbines. One provides peak power, and one provides baseload. And they will produce power at wildly different costs, because each last 30 years, and the cost is dependent of the number of hours they run each year. The baseload power plant is cheaper just because it runs more.
Wind and solar only need to be out of sync a few days a year. Maybe a week. And you are right back where you started.