MIT and the Florida Institute of Human and Machine Cognition is not currently powered by solar energy but anything in the high tech world is possible.
This "bot" "FastRunner" is one of the fastest and most agile robots to date. It's movement is based on how ostrich legs work. The bot's legs sport a motor and springs that store energy then release that energy (similar to solar energy storage?) for sustained quick movement. Using minimal battery power, the bot can zip up hills and climb up and down stairs as well as around obstacles at a fast pace while carrying heavy gear.
The bot will eventually be able to carry any type of payload that it's locking and unlocking legs can carry. They are envisioning all sorts of military and non-military uses for these bots as well as the creation of "humanoid" bots.
Here's the movement of FastRunner in it's current developmental stage:
Dr. Russ Tedrake of MIT says FastRunner can hit 27 mph currently and they hope to see it speeding away at over 50 miles an hour at some point.
More details about FastRunner at Wired.