They are split into different power categories with two championships for each one. (xboxenthusiast.com)
The Mazda Road to Indy (#MRTI) is a similar program that includes Mazda - powered categories of USF2000, Pro Mazda and Indy Lights. (weathertechraceway.com)
The leading five communities at this point in the competition in the percentage of total electricity that is coming from green power category (in order) are: Brookeville, Maryland; Swarthmore, Pennsylvania; Bellingham, Washington; Rivers Falls, Wisconsin and Corvallis, Oregon. (earthtimes.org)