We can just add usb port to regular wall sockets and make a new power plug with that.
Of course the socket should be backward compatible, but any new devices would require the full plug and responding to the protocol.
Over 10 years we could have an effective grid-wide gigawatthour battery. And everybody would only pay for it like 5 USD every time they buy a new device :)
The cost of a cheap microcontroller, power regulator and an usb plug is like <5 USD. And the possibilities of energy savings are huge. There are also big usability improvements (want to have lights learning your habits and pretending you're home when you're on vacations - someone will make that product).
Want to make sure you switched off that iron when you went to a party? No problem - connect with a smarpthone and check (and switch it off if needed).
There could be several categories of devices with different priorities and default power settings that you could change if you want to:
- background, critical
- background, optional
- background, opportunistic
- interactive, critical
- interactive, optional
- interactive, dangerous if left alone
- bidirectional (like Tesla wall, or a car charger if you want to power your house from your car battery when there is a blackout)
And the house could detect if you're home, and disable the iron if you're not and throttle the freezer and all heaters to optimize the power usage.
Automated vacuum cleaners nad chargers could start by themselves when the energy is effectively free and stop for a moment when there's a shortage.
This will get especially important when electric cars are more common - you don't want everybody to start charging them when they get back home.
A grid supply status, could empower next gen energy saving home appliances. This could be implemented as simple as pricing, the ultimate incentive. Price would fluctuate on the wire, just like it does for energy market.
Why? I lived through one such change in last 30 years (switching from 2-pole europlugs to CEE 7/7). They are backward-compatible, but so would be the usb+power plugs.
We also switched from 60 Hz 240V to 50Hz 230V some time in 00s (don't remember exacty, it was a non-event).
As for incentives new electronic devices should simply be reqired to have these plugs and microcontrollers, like now we require them to have fuses and certain wire gauge, etc.
Why depend on a hack when you can do it right?