I would have thought running on a bio fuel like methanol has got to be a positive if the sport ever decided to market itself in these environmentally sensitive times.
If you're looking for alternatives then electric is your only option. Development of petrol engine for speedway now would be a huge step back.
Women and Men in sports
perhaps I should have said Figure Skating, Curling, Angling, Badminton, Table Tennis, Ten pin Bowling, Mixed Hockey, Diving, Gymnastics, korfball, long distance swimming, Synchronized Swimming and the Discus world record is held by a woman