1 megawatt hour equals 859845.227859 nutritional calories. At 500 calories an hour, that eqauls 1719.690455718 hours of riding. I think that represents about 20000 miles of riding (at 12 miles an hour) ... which is about what I've probably done in my life. This is equal to 1 eco-credit. I think I should be able to sell this eco credit. If you'd like to buy it, please let me know and I'll tell you where to send the $9.95.
Oh wait. One megawatt hour equals 3412141.63313 BTU's. If I divide that by 125,000 (BTU's in a gallon of gas) I get around 27, or the amount of gas I buy in a week when I drive. If I always ride that means that about 1 eco-credit a week -- what I saved. Over 3 years (not including the rest of my life), that's about 150 credits. Times ~$10 = $1500. Not bad.
Feel free to start buying eco-credits.