Its still really confusing. A better title would be "When solar power from batteries are available, costs plummet"

Or since power has no provenience, "When batteries are available, electricity prices fall"

This doesn’t really capture their meaning though. They are describing a change in how the solar generated electricity can be treated due to the changing battery prices.

Arguably your edit is more factual. But part of the job of the title in an editorial like this is to tell you what their perspective is.

I assume the intended meaning is “reduced battery costs make around-the-clock solar-generated electricity possible”. I don't think it's possible to predict how technical changes in electricity production and storage impact prices.

I think they meant "viable" instead of "available"

Just read the subhead. It explains everything.

Ember’s report outlines how falling battery capital expenditures and improved performance metrics have lowered the levelized cost of storage, making dispatchable solar a competitive, anytime electricity option globally.

I.e. making it a viable option.

Well they are two different words with two different meanings. Both are true in this case. “Available” in the sense “obtainable,” “ready for use,” “suitable for a purpose” or perhaps “available to investors”

Baseload, ideally.