In the sunniest parts of the world, solar and batteries are already the cheapest way to build new power generation capacity on an unsubsidized full system cost basis, and that cost advantage is expanding quickly.

By the end of this decade, solar and batteries could affordably supply 90% of electricity for most of the world’s population at less than €80/MWh—that’s a full system cost, including fuel-based backup, for about US 8.7¢/kWh. While this is already cheaper than building a new gas-fired grid, given that European gas prices spiked to ten times their normal level during the 2022 energy crisis and remain volatile today, the gap is only likely to widen.

But beyond 2030—well within the lifetime of any new power generation system built today—solar and batteries will almost certainly be the cheapest, most reliable, and least volatile way to expand a power grid. Doubling down on fossil gas generation under these conditions, as many governments are contemplating, would be a terrible mistake, both economically and geopolitically.

That is the central finding of a model developed by Tom Brown, professor for Digital Transformation in Energy Systems at the Technical University of Berlin. Tom also led the development of the open-source toolbox Python for Power System Analysis (PyPSA), and based this analysis on a blog post titled “Solar and batteries can power the world.” If you doubt the conclusions, you can run the model and test the assumptions yourself.

In today’s episode, we’ll dig into how the model works, what happens when you add wind to the mix, and why battery costs could halve again by 2050, making solar-dominated grids dramatically cheaper than anything we can build with gas. We’ll also examine the land question and find that powering the world with solar would take just 0.3% of global land, a fraction of what we currently devote to livestock. And we’ll revisit how to meet that last 10% of demand, a topic we last explored in Episode #188 with Paul Denholm of NREL, and hear Tom’s case for methanol as a surprisingly practical backup fuel.