Enough to counter the disappearance of the 85% of export income Saudi Arabia gets from oil?

Enough to counter the fact that Russia gets 52% of its federal revenue from oil and gas?

I find it hard to believe that making desalination a little cheaper, or transport a little less expensive will even come close to counter balancing those sort of percentages.

And even if it did, the relative importance of nations will change. Nations that were important because they had fossil fuels will become less important, and nations that were held back by lack of resources could become more powerful.

Those sorts of changes in power balances would cause a lot of turbulence.