Energy prices are not plummeting globally, the drop that did happen can primarily be put squarely on america developing enormous new oil resources which broke the opec cartel which couldn’t get its act together in the new environment (and was trying to bankrupt the more expensive NA oil by dumping below production cost for tar sands). Geopolitics and world events have ended this period of cheap oil which is still fluctuating but the contribution of wind and solar is just not big enough yet to dominate the energy market.