With all due respect, you appear to fail to understand the distinction between base load plants and topping plants.
Base load plants supply the huge amount of power that MUST BE THERE 24x7. Topping plants supply the variable amount that is or is not needed depending on seasons, weather, uncharacteristic heat waves, sudden cold snaps, Pink Floyd concert light shows...
MOST of the power demand is base load demand. Heating and cooling don't stop. Water pumping doesn't stop. Hospitals run 24x7. Ditto traffic lights.
For topping plants, there are lots of choices, natural gas being a popular one. For base load plants, there are at the moment exactly three viable choices: hydroelectric, coal, and nuclear (to be precise, negative void coefficient pressurized water reactors). We are maxed out on hydroelectric power: every dammable river in the country has already been dammed. Coal is about the dirtiest power generation technology known to man, as well as one of the most dangerous (Google "black lung disease" someday). That leaves nuclear as Hobson's Choice, if you actually care about environmental and safety issues. (Hint: Of the three, only one emits significant quantities of carbon dioxide.) (For that matter, if coal plants were held to the radiation release limits applied to nuclear plants, it would be impossible to light up a coal plant, because of the radioisotopes in the coal (carbon-14 being the big one) that go straight up the smokestack and into the atmosphere.)
*ANY* base load plant costs a lot of money and takes a long time to build, because, by their very nature, they are BIG.
Finally, observe that wind and solar are utterly unsuitable for base load, because the wind doesn't always blow, and the sun effectively "goes out" for several hours every day.