As a person with experience in the environmental/energy and congressional space, a few comments:
- I haven't seen a recent Congressional Budget Office score, but other federal sources have put the total value of 'tax expenditures' (that is, lost revenue from tax breaks) for fossil fuels at roughly $40 billion over 10 years (i.e. $4 billion per year). There are other forms of subsidy, of course (e.g. Dept. of Energy spends a little under $1 billion per year on research and the like, for example) but $100 billion per year sounds much higher than other numbers I've seen.
- Following on that point, solar and wind currently do have pretty significant subsidies on the whole; by some metrics they receive more per year than fossil fuels at this point. That said, if one considers in terms of total subsidies received over the years, fossil fuel energy has received magnitudes more than cleaner energy sources.
- Going a bit further, it doesn't get a lot of attention but last year's extensions of the Production and Investment Tax Credits for (most) wind and solar is still a big deal. More investments in clean generation are great, certainly, but at this point there are other parts to consider. 'Modern' grids, energy transmission improvements, much better energy efficiency, etc. - all these and more will play crucial parts in getting real GHG reductions, not just building solar panels and wind farms.
- Practically speaking, without trillions of dollars and/or much higher energy bills the U.S. isn't going to be able to fully curtail fossil fuel usage by 2030 (2050 won't exactly be easy either). Considering that we only have so many years and the political will to do something truly massive in scope just isn't there, I'd argue it's better to focus on more viable paths to reducing GHG emissions than shooting for the moon. This isn't to say we shouldn't bother trying for the big things, but it's sensible to have lots of contingency plans.
- Regarding 'clean coal', carbon capture & sequestration (CCS) is (more or less) a thing. While it's true that several of the high-profile CCS plant projects haven't panned out awesomely, there are other forms of CCS application that are more proven. While not preferable to proper clean energy, as a transition tool I'd argue CCS may turn out pretty important. CCS can also be applied in the natural gas context, so getting it right helps even if the U.S. suddenly stopped all coal usage. (and yes, CCS only addresses carbon pollution - coal emits lots of other horrible things, and even if you use scrubbers you still have to deal with the coal ash. So CCS can help but doesn't magically make coal 'clean'.)
- Nuclear's tricky. Lots of reasons, but two of note are 1) the U.S. still has no long-term nuclear waste repository and there's yet to be a community willing to stand up and take all that waste, and 2) as we've seen a few times so far, while nuclear 'problems' are rare they're still not quite worth rounding to zero given the damage that can be caused. I'm not anti-nuclear myself, but... it's really tricky.
- A carbon tax has appeals, but it also has major risks. There are plenty of folks out there trying to use a carbon tax to preempt EPA (or other) standards while keeping the price low enough to not drive the reductions needed (which, unless you write the bill with a proper backstop, wouldn't actually be guaranteed by any carbon price). I'll avoid going into detail, but it's looking likely there will be some significant risks here within the next 6 months - and that's if Clinton is elected. (No need to mention Trump's stance.)
- Even if the Dems retake the Senate and Hillary wins the presidency, unless the Republican party completely implodes it's going to be an awful time next session. Most of the House Rs who'll lose in November will be the moderates, leaving a more radical Republican House majority and Republican House leadership less able to resist the most unpleasant people of the hard-right faction. This is also a House Republican majority that has been actively hating Clinton for several years going - her becoming President is likely to make them more dedicated to taking her down and pursuing a scorched-earth strategy. Don't expect the drought of legislative activity to end, I guess I'm saying.
Finally, I'll just note to those who might be left here contemplating a Trump vote: setting aside everything else about his policies and character, a President Trump would likely mean a Republican House & Senate, which in turn would mean a reconciliation bill the likes of which we've never seen. Long story short, reconciliation means no filibuster, which means the minority party gets no voice and no influence on the process. Existing rules limit the scope of what can count, but some Republicans in Congress think they've found a way to change how things are calculated in a way to massively increase the scope. It's a little harsh to say this, but given the current state of the Republican party I would rather not give them a legislative blank check at this point in time.