TigerTim saidTo correct some common misconceptions:
(1) Nuclear reactors cannot provide more than a certain percentage of supply [known as the baseline] because they cannot be switched on and off at will.
(2) Nuclear is not renewable and the known deposits of Uranium are actually surprisingly small [if the entire world's energy consumption was nuclear, they would last around 30 years].
(3) Despite the claims of nuclear reprocessing, there has not been a single commercially successful reprocessing effort to date.
(4) The transmission infrastructure of the US is in a terrible state. Correcting this would be far more effective than a great deal of piecemeal efforts on renewables [this would facilitate far better placement of renewables, e.g. hydroelectric/nuclear efforts, solar panels in deserts, wind turbines in windy places].
1) The French are getting 80% of their electricity from uranium reactors and are exporting considerable power to Germany because Germany's PV solar systems are basically an economic disaster; their availability factor is very low. Moreover, French nuclear plants are doing load following. Doing so requires minor modifications to the reactors. Because they can vary the output over a considerable range, they do not have to switch them on and off. And, I am well aware that if a pressurized water uranium reactor is switched off, it takes a few days to restart it because of the buildup of xenon, which is a neutron poison, and the reactor cannot be restarted until the xenon has dissipated.
Note that the liquid fluoride thorium reactor (LFTR) can easily load follow. Also, if it is shut down, there is no xenon problem since the xenon can simply bubble out of the liquid fuel.
2a) Although uranium nuclear is not renewable, it is sustainable. If the uranium were used efficiently (and we are not currently using it efficiently), we could mine enough uranium to last for more than a thousand years after which it could be extracted from sea water or from the ash generated from coal-burning plants. Thorium is about three times as abundant as uranium so if we switched to using thorium instead of uranium, we'd have enough thorium to last for thousands of years.
2b) In a sense, wind and solar are not renewable the reason being that the materials used to manufacture wind and solar systems have limited availability; wind and solar systems have limited lives and must be replaced periodically, just as other generating systems must eventually be replaced (or at least be rebuilt).
3) It is probably true that to date, there has not been a single commercially successful reprocessing effort. That's because it is currently cheaper to mine more uranium or use uranium from nuclear warheads than it is to reprocess. Obviously if we continue to throw away used fuel instead of reprocessing it, the amount of unmined uranium will eventually decrease to the point that reprocessing used fuel will become economical. Also, when producing nuclear power, the cost of the nuclear fuel is only a small percentage of the total cost. If I recall correctly, it is only about 5% of the total cost so even if reprocessing doubled the cost of the nuclear fuel, the cost of the fuel would still be quite low. Doing so would prevent future scarcities of uranium thereby greatly delaying future cost increases. It would also solve the waste problem.
4) It is true that our electrical transmission system is jury-rigged and held together with bubble gum and bailing wire. However, improving it would not make major "renewable" sources of electricity practical. The main problem with major "renewables" is that they are intermittent sources of power, i.e., they do not provide power on a continuous basis. Hydro can, but we are already utilizing most of the available hydro locations. Geothermal can, but it is not available in all locations. Moreover, there is some evidence that geothermal can cause destructive earth tremors and that eventually geothermal sources gradually cool to the point of ineffectiveness as we continue to extract heat. However, it could become more practical as more is learned about it.
Wind and solar could, in theory, provide sufficient power in the U.S., but energy storage would be required and as of now, the cost of storage would be astronomical. Moreover, in countries with a very high population density, wind and solar could not provide sufficient power and we cannot ignore the needs of other countries.