I still think the biggest breakthrough is to think from small to big. Big energy grids have the problem of always being polluting whatever technology. And because the investments are so big, we get into another technological lockin. Furthermore geopolitics are getting really scary out there with Russia and China being in the lead on 3 continents (Europe, Asia and Africa).

If we think from small to big, this will easily be solved. One house (with off-grid technologies) in one village or city, in one country. Nested and open. I really hope these engineers will develop the small solutions. I hope for hydrogen. But IoT is already working with small magnetic energy. We can include piezo-technology. And there is now a lot of research on the fourth phase of water. Who knows what will be...