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_23840623_4 (dirty_electric_grid_rocky_mountains__denver_ VARCHAR, epa_rated_combined_fuel_economy VARCHAR)

### Question ###
How many dirty electric grid rocky mountains (denver) vehicles have an  epa rated combined fuel economy of 102 mpg-e (33kw-hrs/100mi)?

### Accurate SQL ###

SELECT COUNT(dirty_electric_grid_rocky_mountains__denver_) FROM table_23840623_4 WHERE epa_rated_combined_fuel_economy = "102 mpg-e (33kW-hrs/100mi)"