CREATE TABLE table_24620684_2 (clean_electric_grid_california__san_francisco_ VARCHAR, vehicle VARCHAR)

When bmw activee is the vehicle type how many clean electric grid california (san francisco) measurements are there?
SELECT COUNT(clean_electric_grid_california__san_francisco_) FROM table_24620684_2 WHERE vehicle = "BMW ActiveE"
SELECT COUNT("clean_electric_grid_california__san_francisco_") FROM "table_24620684_2" WHERE "BMW ActiveE" = "vehicle"