[Schultzy]

What do you mean by "loosely coupled"?

Are you saying that the electricity flowing into Volts and Leafs hitting the market doesn't really come from a polluting source or merely that it doesn't have to?

...or am I missing your point completely?

[hackerblues]

There are three components.

Generation -> Grid -> Homes and Business

It is possible to change the type of generation without having to change the way electricity is taken out of the grid to power things. This makes it easier to make changes in the type of generation. Changing from coal to solar to nuclear just involves making a new connection between the power plant and the grid. Everything else then just works as normal.

By contrast, if we converted energy into "Dragon Tears" instead of electricity we would need to lay down a whole new Dragon Tear distribution network so that people could use that energy. Then, a scientific break through occurs and we are able to use the much more efficient "Unicorn Blood". But now we have to rip out the Dragon Tear distribution network and install a new Unicorn Blood network.

[stoney]

The problem with switching to electricity is that the electricity distribution network has a limited capacity. Increasing the capacity of the connection to every single dwelling would be enormously expensive (and energy consuming!), so there are limits to how much demand can easily be switched to the electrical network.