No need for exotic solutions. All that is needed is proper application of current technology.

Decentralisation of power generation

By adding a large number of low productivity devices on the grid, gradually, you can get rid of the troublesome non renewable resource hungry power stations. At the very least, you can prevent the building on new ones.


For the cities

Install a windmill on top of each high-rise. One windmill is enough to supply electricity to the high-rise. Wind in a city at this altitude is almost constant. That would remove the building from the power grid. Excess power can be shunt to the existing power grid.

Business high-rises are self sufficient during the day and power residential area during the night (If they would only turn off the lights at night.).

Residential high-rises are self sufficient during the night and power business area during the day.

For all areas

If the area is located near a river or sea with enough current, underwater windmills (works like windmill but with water) can be used. At proper dept, it is unseen and does not affect water traffic.

For individual homes, scaled down hydro dam and windmills and underwater windmills and solar panels and battery banks with bio diesel generator set-up can be used to totally get off the grid. (At the minimum, windmill solar panels and battery) Though the grid is important for backup and sharing electricity.

Installing such a set-up on a larger scale such as for, lets say, 200 homes, you have a micro power station every 10 blocks consisting of a powerful windmill and bio diesel generator in the centre and solar panels and battery bank at every home.