Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_24620684_2 ( clean_electric_grid_california__san_francisco_ VARCHAR, vehicle VARCHAR )

### Question ###
When bmw activee is the vehicle type how many clean electric grid california (san francisco) measurements are there?

### Accurate SQL ###

SELECT COUNT(clean_electric_grid_california__san_francisco_) FROM table_24620684_2 WHERE vehicle = "BMW ActiveE"