Nothing so long as we're doing it sensibly. Wind and solar are stupid. More hydroelectric? Great! More nuclear? Fantastic! Geothermal? All for it! Wind and solar suck as electrical production sources.
Lurch doesn't understand that there are no fossils fuel power plants. Fossils don't burn. I suppose he is using the term to mean coal, or oil, or natural gas, or perhaps all three.
You are correct. Wind and solar are stupid. They don't produce power reliably and are horrifically expensive. Trying to balance a load with these power stations is impossible.
Hydroelectric can't be built in all locations. Further, it can only produce so much power per installation. The Hoover dam, which is generating power mostly for California, is using more water than can be sustained in normal river flow. The result is predictable. Headwater (Lake Mead) is falling while waters downstream are normal (such as around Lake Havasu, on the same river). At least hydroelectric plants can adjust power generation to load quickly.
Nuclear energy uses very little 'fuel' for the power plant. California is closing them because they are 'hazardous' and 'poisoning the environment' (or some other stupid Church of Green phrase). They can also adjust power to load quickly.
Geothermal is only available in limited areas, due to the difficulty pumping coolant very far vertically. You basically need a nearby active volcano, and they just aren't available everywhere.
Which leaves natural gas...a renewable fuel, clean burning; or
oil...a renewable fuel, can be pretty clean burning; or
coal...a cheap and possibly renewable fuel, can be pretty clean burning.
All of these types of power plant can easily adjust themselves quickly to changing loads and can produce a lot of power in a small space. All of these fuels are cheap (meaning they are available). Two of them are renewable fuels, and coal may be renewable, but it is not known yet. There certainly seems to be a lot of it though.
Most power generation is via natural gas. This is for a reason.
This unnatural fear of any of these fuels is ridiculous. CO2 is not a pollutant, these fuels can burn quite cleanly in a properly designed power plant, and they are plentiful, making it more attractive for grid operators to buy energy from it.