SELECT COUNT(vehicle) FROM table_24620684_2 WHERE clean_electric_grid_california__san_francisco_ = "100 g/mi (62 g/km)"
Ketika 100 g/mi (62 g/km) adalah Clean Electric Grid California (San Francisco) berapa banyak kendaraan?
CREATE TABLE table_24620684_2 (vehicle VARCHAR, clean_electric_grid_california__san_francisco_ VARCHAR)