Consider using the term "low-carbon energy" in place of "renewable energy". We want to promote the right stuff. Biofuel is considered renewable but is high carbon. Nuclear fusion would be low carbon but not considered renewable. The difference matters hugely for future energy policy.
Renewable is a more strict term than carbon-neutral, it's true, but all "renewables" are by definition closed-loop and hence carbon-neutral.
As an extreme case in point, wood in particular is a horrifying energy source due to health detriment from particulates.
Have a look at some data:
https://partofthething.com/thoughts/wp-content/uploads/ipcc-...
Source: Schlomer S., et.al., 2014: Annex III: Technology-specific cost and performance parameters. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the 5th Assessment Report of the IPCC
https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5...
So I think it's fair to actually consider nuclear fusion and nuclear fission in breeder reactors both to be renewable. B. Cohen said the same about breeder fission reactors in the 1980s [1].
Uranium in seawater can be extracted at 10x world energy scale for billions of years. It replenishes continuously through crustal erosion and plate tectonics. Sounds pretty renewable.
But according to policies we're writing today, the term renewable does not include fusion or fission in breeders. I consider this problematic. Thus I think we all should prefer either "sustainable energy" or "low-carbon energy".
[1] http://large.stanford.edu/publications/coal/references/docs/...
High-burnup nuclear power, under reasonable assumptions, is sustainable for hundreds of thousands of years. Fusion is presumably sustainable as long as the Earth exists, as are solar and wind. Coal is not sustainable at all.
