Today's electricity grids are kept stable by the inertia of spinning masses — mostly fossil fuel generators. But what happens when those spinning masses are replaced by inverter-based resources like wind, solar, and batteries? The answer is that inverters must take over the stabilizing job, becoming "grid-forming" rather than merely “grid-following.” I chat with two experts about how grid-forming inverters work, how many are out there, and what the future holds for them.

Lithium-ion dominates the battery world, but alternative chemistries are finding their niches. I talk with Landon Mossburg, CEO of Peak Energy, about using sodium-ion batteries for large-scale grid storage. They trade some energy density for a longer life and radically lower operating costs, thanks to an innovative, passively cooled design. We also explore the geopolitical opportunity of competing in a battery market that China doesn't already completely own.

This week I talk with Dan Stein, whose organization Giving Green seeks to align climate philanthropy with the principles of effective altruism. But what does "effective" mean in the face of fossil fuel autocracy? We discuss the difficulties of measuring systems change and debate the limits of technocratic solutions.