The City by the Bay just took a big step toward its goal of powering the city with 100% renewable electricity by 2025 with the passage of a bill that will require new residential and commercial buildings to include rooftop solar, either solar electric or solar water heating. This ordinance, which was unanimously passed by the city's Board of Supervisors, is essentially the extension of an existing regulation that required new building projects to designate 15% of a building's roof as being "solar ready," which means unshaded and clear of obstructions and reserved for solar.
With the new ordinance, this 15% solar ready area will not only be reserved for solar, but will also be required to actually have solar on it, which is a big missing piece of the original. The regulation will only apply to new construction of buildings of less than 10 floors (which is also the case with the original), and in an already highly developed metropolis such as San Francisco, the demand for new buildings with less than 10 floors to them isn't nearly as high as in a smaller, less dense city, so it's not exactly a massive solar plan for the city, by any means. And as Fortune points out, it can be a particularly difficult city to for building development, so this solar addition may just add to the potential challenges for builders.
However, it certainly is symbolic, and may help set a precedent for other cities, and it will actually help produce more clean electricity towards the city's 100% renewable goal, so it's not an empty gesture. The Better Roof program, which was introduced by Supervisor Scott Wiener, could potentially boost the current 24.8 MW of rooftop solar in the city by an additional 7.4 MW, according to the City's Department of the Environment, which would add the equivalent amount of electricity to power about 2500 homes in the city annually. That's not a huge amount, but it is a step in the right direction, and could help cut the city's carbon footprint over the long run.
“By increasing our use of solar power, San Francisco is once again leading the nation in the fight against climate change and the reduction of our reliance on fossil fuels. Activating underutilized roof space is a smart and efficient way to promote the use of solar energy and improve our environment. We need to continue to pursue aggressive renewable energy policies to ensure a sustainable future for our city and our region.” - Supervisor Scott Wiener
According to the San Francisco Examiner, the city will also be exploring some follow-up ordinances in the near future that could extend this one, such as allowing builders to include green roofs or living roofs to meet the requirement, instead of installing solar. The new ordinance will go into effect on January 1, 2017.