Yep , I understand the energy density of coal and oil . They are fantastic energy sources . That's why , as I posted previously , it's going to take a long time to wean ourselves of fossil fuels .
Don't know why people fuss over wind turbine charts ? We know that the wind doesn't blow all the time . Just as we know the sun isn't up for 24 hours . But , these resources are quite predictible . And , as they are developed they are getting more and more efficient .
But , it still comes back to the storage . That is the key I reckon . You can generate as much as you like from renewables but until you can store it you will always need fossil for backup .
Molten salt does have a big future as does large scale flow batteries in my view . Enviromentally friendly , scaleable , long lasting , can be located anywhere urban or remote .
I still think we will see smallish scale pumped hydro in certain areas . The one they are looking at for Port Augusta seems like it might work . Plenty of elevation , plenty of water and plenty of sun . Be interested to see how that one pans out .
Here's another example of where renewables can be practical .
http://www.abc.net.au/news/2017-09-...hium-batteries-big-success-wa-farmers/8954740
