It developed an electric version of the Phantom a couple of years ago called the 102EX and showed it to customers around the world. But people weren't interested, so Rolls-Royce killed the program. Not to be deterred, however, Rolls is now said to be working on a plug-in hybrid that would countermand some of the shortcomings – like range and recharging times – that killed the 102EX.
The technology would apparently be borrowed from parent company BMW which is developing it for the X5 eDrive and allow Rolls-Royce to reduce its carbon footprint and offer a more environmentally friendly mode of transportation to those who don't want to skimp on the luxury and prestige.
Of course we don't know at this point whether the powertrain would be shoehorned into the Ghost or the Phantom, but we'd expect it to come in sedan form long before a coupe or convertible are ever considered – assuming, of course, that an SUV doesn't arrive first.