Related by context. Frequent words. (Click for all words.) 49 Solar Decathlon 44 hydrogen fueling 43 Design Contest 43 hydrogen refueling 42 X PRIZE 42 Challenge 41 hydrogen powered 41 TTXGP 41 Hybrid Synergy Drive 40 MINI E 40 E# ethanol 40 FIRST LEGO League 39 zero emission 39 bio ethanol 39 Challenge Touring Car 39 compressed hydrogen 39 Destination ImagiNation 39 Automotive Engineers 38 FIRST Robotics Competition 38 hydrogen fuel 38 Lotus Engineering 38 FIRST Robotics 38 Automotive X PRIZE 37 Mitsubishi i MiEV 37 electric hybrid 37 Chevrolet Volt 36 X PRIZE Foundation 36 combustion engines 36 Hydrogen 36 Nissan LEAF 36 Marathon 36 PHEV 36 Smart fortwo 36 Science Olympiad 36 Ampera 36 Alternative Fuels 36 Fuel Cell 36 hybrid powertrain 36 marathon 36 electrically driven 36 powertrains 35 electric powertrain 35 Compressed Natural Gas 35 Ironman 35 Zero Emission 35 Ford Escape Hybrid 35 X Prize 35 combustion engine 35 Hybrid Electric 35 Fisker Karma 35 Triathlon 35 solar powered 34 DARPA Grand 34 Electric Vehicle 34 Ironman triathlon 34 alternative fuels 34 circumnavigation 34 Maker Faire 34 UTC Power 34 proton exchange 34 ultramarathon 34 biodiesel 34 Ironman Triathlon 34 FCX Clarity 34 hybrid electric 34 RoboCup 34 EnerDel 34 SOFC 34 hydrogen 33 NAIAS 33 hybrid propulsion 33 eTec 33 Aptera 33 SYNOPSIS 33 lithium ion battery 33 Tesla Roadster 33 Flex Fuel 33 Bike Race 33 PHEVs 33 Smart Fortwo 33 electric hybrids 33 Boston Marathon 33 SwRI 33 Alternative Fuel 32 Smart ForTwo 32 Mercedes Benz SLS AMG 32 IdaTech 32 internal combustion 32 HEVs 32 i MiEV 32 bio diesel 32 microturbine 32 Chevy Volt 32 EV charging 32 Startup Weekend 32 EVs 32 tailpipe emissions 31 prototypes 31 grand prize 31 renewable fuels 31 diesel