The thing about energy is that it is the foundation of industrial society. The underlying reason that we have the wealth we have is that we harness far more energy than was ever available to any previous civilization. We are also continuously coming up with ways to do more with a given amount of it - i.e. increasing efficiency - but it's still the foundation of everything we do.
Literally every country subsidizes all forms of energy in some way or another. In the case of fossil fuels, in addition to explicit subsidies (of which there are many), there are also subsidies that take place through time: the full price for the fossil fuels we burn today is paid by future generations that have to deal with the global warming and ocean acidification that are caused by the energy we consume today. Exactly how much global warming will happen is still very uncertain, but the price is there and will be paid over a period of thousands of years for energy that is consumed over 1/100 the amount of time. Even if that weren't a problem, they're still finite and would run out eventually, even though last decade's predictions for an imminent peak in oil and gas production were foiled by better extraction technology.
In the case of nuclear power, of course there are still subsidies, both the explicit kind and the implicit time-delayed kind. The latter consists of uncertainties about future meltdowns and about storage of radioactive waste. Storage in deep geological repositories like Yucca Mountain should work on timescales we care about, but there could be accidents getting it to those sites. Nonetheless, more advanced breeder reactor designs, with abundant fuels including U-238 --> Pu-239 and Th-232 --> U-233, and with designs pioneered in the
Integral Fast Reactor along with other approaches such as molten salt reactors (mostly thorium breeders), hold some substantial promise. Unfortunately, budgets for this sort of research were slashed around the end of the Cold War, and regulations on nuclear power have been increased so dramatically thanks to the anti-nuclear movement that nuclear became completely uneconomic despite generous subsidies. Construction fell to 0 by the mid-1990s, and has remained there besides a couple of reactors somewhere in Georgia and/or South Carolina. Had we built out nukes to the extent France did (subsidies included), and especially if we had kept up research on better and safer designs, we would certainly be emitting far less carbon today.
For renewables, of course they are great and both need and deserve to be subsidized. One way or another, and I'm hoping for one of the more pain-free ways, we will end up llving sustainably, by definition - the unsustainable is that which cannot be sustained, on some timescale (in this case we're looking at decades to centuries). Solar power in particular holds enormous promise because of the improving economics of solar cell manufacturing and the vast amount of energy that is hitting the earth to be tapped. The big stumbling block is energy storage from intermittent sources, and progress here has been slower and more disappointing than in solar cell manufacture. It's one thing to get Li-ion batteries that can power phones and computers and luxury cars, and an entirely different one to build out enough batteries and pumped hydro storage to compensate for a cloudy, low-wind period in the winter. If we could build a much better transmission grid, we might be able to use the country's vast size to get power from e.g. the SW to the NE, but this would be an enormous undertaking and we suck at building advanced infrastructure in reasonable time frames at reasonable prices.
I'm am optimistic that we'll somehow muddle through and work it all out eventually, and end up powered by mostly renewables plus a few nukes and a little bit of gas (ideally biogas or syngas, realistically probably still fossil gas) for peaking power by 2100. But it's going to be a slow and drawn-out process, and we'll nearly certainly end up blowing CO2 levels way above 500 ppm, likely about 600 ppm, by that time, with all the attendant climate mayhem.
