CRI听力: San Francisco Moves toward Green Cabs

The city of San Francisco is encouraging green transportation. The use of hybrid and electric cars is being backed with the installation of charging stations throughout the city.

Our reporter Li Dong has the details.



As an initiative to boost green transportation, San Francisco has now changed more than 55 percent of the city's cabs into hybrid cars that run mainly on electricity.

San Francisco Mayor Gavin Newsom is behind the initiative to make taxicabs green.

"Today we are announcing that already 55 percent of all of our taxicabs are running on renewable fuels and are clean and green."

According to the San Francisco Department of the Environment, most of the San Francisco Bay Area's greenhouse gases come from vehicles, and that's a key motivator for cleaning up the city's fleet.

With a range of 100 miles when fully charged, the car has an operating cost of about 2 cents per mile, according to the company.

Range is a key concern for electric car owners, who need to be sure that they won't deplete their batteries and get stranded. This means partnering with other local governments to create a regional network of chargers.

Gavin Newsom says he'd like to work with the public utilities commission to make electric vehicles an energy-storing part of the grid.

"As mayor I've been really trying to organize not just our city, San Francisco, but other municipalities, in fact we have now nine counties that have participated in a memorandum of understanding to create standardized charging stations throughout the entire region and to create a ubiquitous infrastructure for electric vehicles because we don't want one-way trips out of town where you can't get back because you don't have a reciprocal charging station."

The goals of the initiative include helping to fight climate change, reducing energy costs, and lowering dependence on Middle Eastern oil.

Dan Kammen, professor of energy at the University of California at Berkeley, says taxis are a good place to begin large-scale adoption of electric vehicles, because they typically follow regular routes and return to centralized places where they can recharge.

"Well it's probably not that difficult to outfit a region so that fleets of vehicles - taxis, delivery trucks - can be charged fairly easily. And that's because those vehicles tend to have roots around an area and they come back to the same place each night or during the day so they can be recharged. And taxis are a good example, they drive around the region, they tend to come back to a taxi pool in the evening. Some taxis of course go to people's homes but most of them will come back to centralized pools, so there's a good place to charge them up again."

Kammen says most charging should occur at night, when there is less demand on the power grid.

"In most places, the nighttime demand for power is much less than during the day. So the electricity supply system that's bringing in power to major cities for example tends to be used near its capacity during the daytime but at night there's a lot of over-capacity. So bringing in more power at night is easy, it doesn't require more transmission lines, it doesn't require other infrastructure, so you can charge up vehicles when the demand is low, night time, and use them largely during the day when the demand is much higher."

For CRI, I am Li Dong.