Shimano is currently developping an electrical groupset as Mavic did and as Campagnolo almost finished to do.
The firsts prototypes were seen in Mallorca and seem to use wire to transfer the datas. Front and rear derailleurs are huge while shifters use optical gear indicator.
Some parts should be made out of carbon while derailleurs will be leaner.
Some Shimano patents are already availables;
Source: Weightweenies