The original report by Ember [1] is decent but clearly biased.

They assume each battery cycles entirely EVERY day - even in winter. They also assume PV is never curtailed - not even in summer. They of course ignore multi-day weather anomalies. Like wise for weekend/holiday demand variations. etc.

The best part of the report are real world bids of 2025 ESS projects.

[1] https://ember-energy.org/latest-insights/how-cheap-is-batter...