We don't need any breakthroughs. Electric cars could handle the entire peak load with
today's technology, the right incentives, and capital flowing in the right place.
The peak load for South Australia was 1.8 gigawatts. There are 1,275,041 motor vehicles registered in SA.
If you could get all of them turned into electric cars plugged into the grid, it would be a 1.4 kW power drain per vehicle, which is less than the power drain of an ordinary kettle here (240V, 10A, ~2.4 kW).
The cheapest Tesla Model S has a 40kW hour battery meaning it could sustain that power drain for over 28 hours (a total of 51 GWh). It's got a 10kW charger standard, which is more than enough.
So if everyone had the cheapest Model S, kept it plugged in with the ability to send power back into the grid, and didn't mind that their car was sometimes down to 20% charge, you could power the entire grid on solar alone.
That's obviously a set of unrealistic assumptions, but it does indicate that it is feasible to solve the problem like this.
A more realistic set of assumptions:
* 1/10 cars are turned into a Model S base model equivalent
* Through financial incentives, the owners are willing to keep them plugged in
during the day and using up to 20% of the battery to push back into the grid.
* Cars need to shave 0.2 gigawatts off of peak load for four hours to bring
it in line with the rest of the day
That's 800 MWh of power to satisfy peak demand, at 200 MW.
We have 127,504 vehicles, can can use up to 8kWh and 20kW each, giving:
1 GWh of capacity and 2.5 GW maximum power draw.
So it's just enough. Alternatively, 5% allowing 40% usage works, etc. The power draw is insignificant.
Owners can be heavily compensated for pushing energy back into the grid. I won't run the numbers here for length and time reasons, but knocking out peak power usage is incredibly profitable. You're literally decomissioning a large percentage of power plants. It would be feasible to make all the energy your car uses free; likely the lithium ion battery packs, too.
The question is; would 5% of the driving population buy a $50k car if they no longer had to pay for fuel or battery packs? Financially that would probably put it closer to a BMW. I think it's feasible. What about in 10 years when the cars are $20-30k? Undeniably. In 20 years when you only need 2% of the population to be in the scheme due to battery increases and the cars cost $20k? No brainer.
The system would require a smarter grid (so you can plug your car in at work and have it all taken care of), 10 years of Moore's Law for batteries, etc.
But I think the numbers check out, and it means we could go crazy with solar (the explosion in solar must continue to charge these vehicles during the day). What's needed is the will to make it happen.