Renewable power is intermittent power. Or, put another way, renewable power is unreliable power.
People talk about how if we only have grid scale storage, like batteries or pumped hydro, that renewable power can power our economy. They seem to forget that fuel is stored energy. We can mine the earth for "zero carbon" (in scare quotes because nothing is truly zero carbon) energy in uranium and thorium. If renewable energy is "zero carbon" energy then nuclear fission power must be "less than zero carbon" energy produces less carbon than any renewable energy source.
Our future energy will come from a mix of geothermal, onshore wind, hydro, and nuclear fission. Geothermal power is a reliable energy source as we can draw from it as we wish, the energy is stored in the heat deep in the planet. There is a limited rate we can draw from this as taking too much too quickly will cool the local rocks and render it useless. That's no different than hydro, another energy source with an inherent store of energy in water behind a dam. We can only draw from it based on the rainfall in the area that feeds the dam. We can pump water back up the hill to store energy from other sources, and because these are often very large reservoirs with little loss over time we can store energy on seasonal scales. Because hydroelectric dams can vary their power output quickly we can use them to assist in load following with energy sources that cannot vary output quickly. Those sources would be geothermal and nuclear fission.
Nuclear fission is a very reliable energy source. It is plentiful. It is safe, safer than anything else we've used for energy based on energy output to people that have died in producing that energy. Issues of radioactive waste or anything else people bring up in opposition are solved problems or a much smaller problem to address than those from other options. Nuclear fission will be a vital part of our future energy supply.
Wind power has no inherent energy store. Unlike hydroelectric power there's no side benefits like providing a store of drinking water and aiding in the transport of goods by canals and rivers. What wind power has though is simplicity. Wind power is low tech and draws directly from other industries. The generators used in a windmill are not all that different than the generators in a small hydro dam, or large industrial motors. The towers are not that different from those used to hold up power lines. The windmill blades not that different that airplane wings. This is a simple technology and therefore a low cost technology. Well, it's a simple technology when onshore. When offshore it becomes complicated, labor intensive, and too expensive to bother with. Far more expensive than reliable power from hydro, geothermal, and nuclear fission.
I read some idiot that claimed we could use nuclear fission power as backup for unreliable renewable energy. So, we invest billions of dollars in a nuclear power plant. A plant that has largely the same costs to operate whether is ti producing no power or a gigawatt of power. There is a fuel cost but that is so low it is lost in rounding errors. If we have large grid scale storage in batteries or pumped hydro, and reliable energy from nuclear power that only gets cheaper the more energy is drawn from it, then why would we bother with expensive and unreliable energy from offshore windmills and solar?
Grid scale storage isn't going to make unreliable, and very expensive, energy sources like offshore wind and solar viable. Grid scale storage will make nuclear power far cheaper as it brings load following capability to an exceedingly reliable energy source. The uranium and thorium is both a store of energy and an energy source. We can draw from this store largely as we wish, and schedule periods for refuel, repair, and refit when demand is low. These periods can be staggered, unlike solar power where all solar power goes down in a region all at once, and with considerable regularity.
Nuclear power isn't going to be some backup power for renewable energy. It's going to be the primary source we draw upon. Solar power will be for pocket calculators, communications satellites, and remote outposts far from utility lines. We will draw upon onshore wind, hydro, and geothermal energy where the climate and geography allows it. There will be a need for a fast acting store of energy to manage fast changes in demand, be that from natural variations or unexpected losses of capacity from natural or artificial forces. In the short term that will be natural gas turbines. Medium term we can expect more batteries, pumped hydro, and possibly other technology. Longer term we can expect fast acting nuclear fission reactors. This can be from an adaptation of US Navy propulsion reactors, fourth generation nuclear now in the prototype stage, and technologies in development.
This is a solved problem, and renewable energy will actually plat a very small role in that solution.
