The analysis found that a 50-megawatt data center could consume as much electricity as 25,000 new homes. San Francisco's transmission capacity is about 1,000 megawatts, while peak demand last year reached roughly 800 megawatts and is rising. Demand from electrification and other growth could increase by as much as 20 megawatts per year, and building a major new transmission line could take up to a decade.

The report does not recommend whether to extend the moratorium or prescribe new regulations. A Board of Supervisors committee will take up the extension next week; if approved by the full board, the ban could be extended for another two years. Lurie's office declined to comment on its position.

When he signed the initial 45-day moratorium, Lurie said the city would develop a "thoughtful, responsible framework" that prioritizes community needs, keeps electricity rates low, and protects clean water and air, while warning that San Francisco should not take for granted its role as "the national leader in innovation."

The city currently has three stand-alone data centers, including the largest at 200 Paul Ave., with an estimated power capacity of 34 to 41 megawatts. No new applications are pending, but developers have recently explored projects at the shuttered San Francisco Centre mall downtown and on Michigan Street in the Dogpatch. Those proposals, still preliminary, would include some office space.

The report also notes that data centers employ relatively few people for the space they occupy and would replace commercial uses that generate more foot traffic and jobs. Industrial areas are a better fit, the report states, but facilities there could still compete with production, distribution, and repair businesses those zones were meant to preserve.

Among the options the report raises: prohibiting new stand-alone facilities in residential and commercial areas, extending fees charged for housing and other development to data centers, studying a cumulative power cap (50 megawatts is listed as an example), and requiring utility assessments for larger projects. It also suggests redefining accessory-use data centers by power demand—such as 5 megawatts or less—to separate smaller facilities from larger ones that require more review. Currently, accessory data centers inside other buildings are not clearly tracked and do not require a special permit.

The report identifies water use as an area of uncertainty, since cooling consumption varies by technology. It also recommends further study of battery or zero-emission backup systems and limiting generator testing to between 7 a.m. and 8 p.m., with noise capped at 75 decibels at the property line.

San Francisco's ability to curb data center growth regionally is limited. Lower electricity prices have drawn most developers to Santa Clara, which has 56 stand-alone data centers and is itself weighing water-use restrictions. More than a dozen other California cities, including Oakland, Richmond, and Hayward, have enacted temporary or permanent bans.

Planning staff said the city may need updated rules and more information before it can fully assess the trade-offs. The report also notes that state regulators have recently expanded oversight of data centers, including environmental review and reporting on electricity and water use, while local regulations date back more than two decades.