Repost from The San Francisco Chronicle (SFGate)
[Editor:  The San Francisco Chronicle ran three (!) stories on the Vatican Conference on climate change, including two rather stiff challenges to California Governor Jerry Brown.  See below for one.  See also: As California pumps out oil, Gov. Brown says world must cut back … and Editorial: A climate pilgrimage.  – RS]

Mayor touts S.F.’s green vehicle plans at Vatican conference

By Emily Green, July 21, 2015 4:25 pm,

San Francisco will switch its municipal fleet — some 6,000 vehicles ranging from fire trucks to police cars — from petroleum to renewable diesel by the end of the year, Mayor Ed Lee said Tuesday during his trip to the Vatican.

“We’re taking action that is good for the global climate, and at the same time promotes environmental justice in our community by leading to cleaner, healthier air for some of our most vulnerable neighborhoods,” Lee said. “The city of St. Francis is answering the pope’s call for local action on global climate change.”

His comments came at a major conference hosted by Pope Francis focusing on climate change and human trafficking.

Renewable diesel — which can be derived from soybean, palm, canola or rapeseed oil, plus animal tallow and grease — is more environmentally friendly than petroleum, but also more expensive to produce. The city will finance the transition by relying on a mix of federal and state rebates, which administration officials said makes biodiesel available at or below the cost of regular gas.

San Francisco has some of the most progressive environmental policies in the country. From 1990 to 2012, it reduced greenhouse gas emissions by 23 percent, said Roger Kim, a senior adviser to Lee on the environment. And it has a goal of reducing carbon emissions by 40 percent below 1990 levels by 2025.

It began moving away from petroleum diesel six years ago by transitioning to a blend of fuel that is 20 percent biodiesel and 80 percent petroleum diesel. Last year, the San Francisco Fire Department piloted the use of 100 percent renewable diesel for its fleet.

Renewable diesel is not the same as biodiesel. While both derive in large part from plant and animal oils, they are produced through different chemical processes.