> In fact if green is what you want, nuclear (or if we are lucky Fusion) is the way to go but the environmental organizations are for some reason worried about that.
> It's not just a matter of the market and political will,
That's absolutely untrue, nuclear is waaaaaaay too expensive and old-fashioned to compete in the modern world.
Take a few seconds to look at any of the attempts at construction in the Western world. Nuclear is super expensive, and not nearly scalable enough. In the US, Vogtle and VC Summer have been nuclear disasters, but economic disasters. They had a super-supportive regulatory environment and neighbors around the construction sites, but it's just not feasible to build at a reasonable cost.
Nuclear is such a terrible idea that there's no way to get private funding for it; it has to have huge amounts of government level backing for it to become even vaguely economic feasible. Look at the UK's attempts to sell their nuclear generation capacity, all of a sudden when they were writing financial documents they had to not lie, and they couldn't get anybody to buy them. And now the UK has the economic disaster of the new Hinkley construction.
There's a batch of small-moduler reactor (SMR) startups that may improve the cost and scalability of nuclear, but I'm extremely skeptical. Such SMRs have long been rejected as too costly, it's not at all clear what would make them competitive now. It may happen, but it's further out than the massive scale-back of fossil fuels.
> there are some fundamental limits on how much energy we can get from solar and wind.
These "fundamental" limits are not in the realm of possibility of limiting our current use.
>They are linear solutions to exponential problems so to speak.
I'm not sure what part could be exponential. Our energy use is nothing like exponential, and in developed countries it is increasingly decoupled from GDP and other exponential things. Most of our "energy" use is actually wasted energy due to the inherent inefficiency of thermal electricity generation, or, god forbid, the pathetic efficiency of combustion engines in vehicles.
We don't yet have applications for energy that could come close to any "fundamental limit" from solar. If we do, then perhaps fusion or something will be useful, but fusion is even more of a pipedream than trying to construct