The traditional model of energy distribution via large, centralised grids is changing as smaller private networks powered primarily by renewables come online
For the last century, the power created by large power generators (hydro, nuclear, coal and gas) has been brought to consumers via a grid comprised of transmission lines and cables with varying voltages. The system was like a waterfall with electricity flowing in just one direction, from lines of very high voltage to lines of progressively lower voltages.
This is now rapidly changing. There are now a range of smaller units such as cogeneration plants, which deliver heat and electricity, and renewable energy sources such as windmills and photovoltaic panels. These smaller units are owned by a whole raft of municipalities, households and businesses.