Currently, power adapters have the following problems: - Wasting
materials: Every time, a plug changes, old adapters still in
sales/production circulation will have to be discarded.
Furthermore, sharing adapters could, say, halve their number.
Theoretically, standardization would also make production more
efficient. - Wasting energy: Many old, less energy-efficient,
adapters are still in use, because one cannot upgrade them (due
to their proprietary plugs). Also, devices have no way of
signalling the adapter when they are done charging. - Lack of
convenience: Non-standard plugs means you cannot share the same
power adapter between devices and that once a proprietary plug
falls out of fashion, you might not get a new power adapter for
it, any more. A company calleed GreenPlug has come up with a
nice solution: - A standardized plug: It builds on the USB plug
(which is slowly becoming a kind of DC standard), so its adapter
can charge USB devices. - A protocol for communicating power
needs: If a device is aware o