AbstractTowards low carbon living and clean air quality is CLP Power Hong Kong Ltd. (CLP)'s energy vision and to achieve this goal, the promotion of a cleaner mode of transportation in Hong Kong has been one of CLP's key green initiatives. Recently, CLP has successfully converted a few Toyota Prius hybrid electric vehicles (HEV) into plug-in hybrid electric vehicles (PHEV). Different from the HEV, a PHEV allows the driver to plug into a socket to connect the vehicle to the electrical grid to charge its larger battery pack that replaced the original smaller one. The objective of the conversion exercise is to test the capability and gauge the benefits of the converted PHEV to run on electricity as much as possible, whilst keeping the capability to switch back to conventional combustion engine if required for longer trips. This paper addresses the conversion technical details and shares the operation experience of employing a PHEV in the corporate fleet as well as discusses the underlying business assessment...