Retro-fitted Toyota Prius runs on CNG
Talk about lowering the carbon dioxide levels down in a hybrid. This retrofitted Toyota Prius emits 20% less CO2 (80 g/km). IFP (Institut Français du Pétrole) is presenting a CNG-electric hybrid prototype vehicle based on the Toyota Prius at this Challenge Bibendum, running in Paris from 8-12 June 2006. IFP co-developed the CNG Prius with Gaz de France (GDF).
Source: http://www.greencarcongress.com/