The PG&E Mission Substation is a beautiful 1948 ultramodern building located at 8th and Mission.
"In 1948, the magazine Architect & Engineer hailed the building, designed by San Francisco architect William Merchant, as “ultra modern.” The magazine noted that the substation’s “new 110,000-volt underground transmission cables to the station will bring high voltage power into the heart of San Francisco for the first time in history.”" [source]
It has two beautiful cast-stone reliefs on the 8th Street side. They are called "Power and Light" and were created by sculptor and painter Robert B. Howard. This is a nice article about the reliefs and about Robert Howard.
In 2013, a series of upgrades were completed to the building. For a total cost of $4.4mn, there were improvements to sidewalks, lighting, fences, the building's facade. Additionally, on the Mission Street side, they installed "233 twisted steel fins. Each fin weighs 300 pounds and required a forklift to put each one in place." [source] This article has more details about the upgrades.
The upgrades were carried out by Dilworth Eliot Studio. On the project page they've provided some neat details about how they made the steel fins: "The team collaborated with metal fabricators to design and engineer all steel components, utilizing state-of-the art laser-cutting and water-jet equipment for the perforated fencing and gate panels, and resolving the challenge of twisting the 1" x 8" x 12' long steel barricade fins to create the undulating pattern which moves through the nine planters along Mission Street." There are also more photos on the project page.
Outages and Fires
There was an outage and fire at the substation in 2003 and again in 2005.
"On Dec. 20, 2003, a fire in PG&E's Mission Substation caused an outage to more than 100,000 customers throughout San Francisco. The immediate cause of the fire was an electric cable failure. However, a single electric cable failure, by itself, should not cause an outage to over 100,000 customers. An investigation by the PUC's Consumer Protection and Safety Division (CPSD) determined that other factors contributed to the catastrophic nature of the outage - for example, PG&E had not installed smoke detectors despite its own root cause analysis in the aftermath of a previous fire in 1996 at the same Mission Substation that recommended that smoke detectors should be installed; PG&E's operators did not have appropriate information to evaluate the alarm, which caused them to take no action for two hours; PG&E did not have written procedures for coordinating emergency fire response with the fire department; the surrounding insulation materials were flammable; and auxiliary equipment that did not have to be energized was in fact energized and short-circuited, causing the fire. Had PG&E followed the recommendations made in the fire report from the 1996 Mission Substation fire, the outage would not have occurred.
On March 26, 2005, electricity service was interrupted to 25,000 PG&E customers when a circuit breaker caught fire at the Mission Substation." [source]