Clean Energy SF: San Francisco, fog then sun, est. 2026

Vol. 1 - No. 14 - Thursday, September 24, 2026 - Free to readers

Solar ยท Analysis

The island's second act includes a lot of panels

Treasure Island's redevelopment plan promises on-site solar across thousands of new homes. How the phases work, and who actually pays for the panels.

Filed October 12, 2026 By the Clean Energy SF editors Reading time: 6 minutes

I. How the phases work

Treasure Island is not built all at once, and neither is its solar. The redevelopment is carved into districts and sub-phases, and each parcel gets its panels when its buildings go up, not before. So the island will not flip a switch one morning and run on sunlight. It fills in block by block over roughly the next decade and a half, per the redevelopment plan, with rooftop arrays arriving in waves as the towers, townhomes, and parks around them are finished.

That staggered schedule matters to you if you are one of the first residents, because the building you move into may carry solar while the empty lots next door do not yet. It also means the timeline is soft. The island sits on fill poured for the 1939 Golden Gate International Exposition, and preparing that ground (grading it higher against sea-level rise, improving the soil so it does not settle or shake loose) is slow, expensive work. When that work slips, and public construction schedules often do, the solar tied to each parcel slips with it.

II. Who pays for the panels

The short answer is that you do, eventually, just not on a line labeled solar. The master developer builds the arrays into each project, and the cost folds into home prices, rents, and homeowner-association dues the way any building system does. Some of the island's clean-power features are also supported through the San Francisco Public Utilities Commission, which runs both Hetch Hetchy Power (the city's own Sierra hydroelectric supply) and CleanPowerSF (San Francisco's community choice program, where the city buys the electricity and PG&E still delivers it over its poles and wires).

The honest math is harder than a brochure suggests. Rooftop solar pays off through the credit you get for sending power back to the grid, and on a public-power island those credit rules are set by the SFPUC, not by the state net-metering fights you may have read about in PG&E territory. At last public report the island's power is already lower-carbon than the regional grid average because of the Hetch Hetchy hydro behind it, which means each new panel displaces cleaner electricity than a panel in a coal-heavy region would. The climate case is real; the dollar case for any one household depends on rates that can change.

III. Fog, wind, and a low island

Treasure Island has its own weather, and it is not San Francisco's. Summer mornings can sit under a thick marine fog bank that rolls through the Golden Gate and parks over the bay, which trims solar output early in the day, and then the panels catch a bright, windy afternoon once the sun burns through. A rooftop here will not match a cloudless Phoenix roof hour for hour, but the cool, breezy climate also keeps panels from overheating, and hot panels lose efficiency, so the fog is not pure loss.

The bigger quirk is that the island is flat and low. Everything (the new grid equipment, the ground-level solar and battery gear, the streets themselves) is being raised and the land built up to buy decades against a rising bay. That raising is part of why the panels cost what they cost, and part of why this desk reads the island's solar promise as tied to its flood-defense promise. If the ground work falters, the clean-energy plan sitting on top of it does too.

IV. Worth watching this month

1. The Treasure Island Development Authority posts board agendas before each meeting, and the ones carrying sub-phase or sustainability updates are the ones worth reading closely, while most are routine.

2. CleanPowerSF and Hetch Hetchy Power rates are set by the SFPUC and revisited on a regular cycle, so watch for any scheduled rate change, since that is what moves the payback math on island solar.

3. The next parcel construction milestone (a building topping out or opening) is a concrete sign of roughly when its rooftop solar comes online, and developer updates list these.

4. The California Energy Commission periodically updates the state building-energy standards that govern new-home solar, and a revision there can quietly change what future island phases must install.

5. California ISO grid conditions, especially tight evening hours in late summer, are worth a glance because they show why local solar-plus-storage on islands like this one is valued beyond any single household bill.

Frequently asked questions

Who is my electricity provider on Treasure Island?

Not PG&E. The San Francisco Public Utilities Commission supplies the power through Hetch Hetchy Power and CleanPowerSF, though PG&E still owns the wires that deliver it. Your bill and your solar credits follow the city's rules, not PG&E's.

Will my building have its own solar?

It depends on when and where it was built. Panels are added parcel by parcel as construction finishes, so newer buildings are more likely to carry them. Check the project's own documents or ask the developer for that specific address.

Does the fog make rooftop solar pointless here?

No, it just lowers the morning yield. Foggy summer mornings cut output, but bright, cool afternoons help, and cool panels run more efficiently than hot ones. It is a weaker solar site than a desert, not a dead one.

Is the island safe as it fills with people and panels?

The plan raises the land and infrastructure to defend against a rising bay over the coming decades, and that flood work is deliberately tied to the build-out. It is honest to say the clean-energy plan depends on that ground work holding up on schedule.

References