I agree with you and it will remain so until a suitable baseload generation system can replace coal/gas. The tech for this is already under development. Solar Thermal provides excellent baseload generation but is as yet more expensive than coal but cheaper than gas. Geothermal is too costly to develop- in Aus due to the depth require to drill to access hot rocks.
Pumped Hydro is indeed a going concern to replace coal as well as gas in the near term. with one hydro project I read about recently using a disused underground coal mine as a base reservoir. Aus has literally thousands of sites suitable and acceptable for pumped hydro.
But the big baseload supply is as yet not fully developed but will be within a decade. Hydrogen can even be used as a substitute for LNG/CSG in gas generators and, I've read but remain sceptical, in coal generators.
Yes, youre quite right that the transition process will occur over a few decades most likely. Only an extremist or one who knows nothing of generation would suggest "a total wipe out" of old technology.
