There was never any doubt about the magnitude of these, the challenge was always in harnessing them so as to meet demand.
Today we are well advanced in meeting that challenge, while also testing the practical limits of doing so from wind and solar (variable renewable energy, VRE).
In line with the "landlord-tenant" problem discussed in the energy efficiency literature, both ownership rates and responsiveness tp prices are substanitally lower for rented properties, particularly those with lower income tenants.
Technology to utilise the forces of nature for doing work to supply human needs is as old as the first sailing ship.
The US average EROI across all generating technologies is about 40.
The major published study on EROI, by Weissbach (2013) showed: “Nuclear, hydro, coal, and natural gas power systems (in this order) are one order of magnitude more effective than photovoltaics and wind power.” This raises questions about the sustainability of wind and solar PV which have not yet been addressed in national energy policies.
The relatively dilute nature of wind and solar mean that harnessing them is very materials-intensive – many times that from energy-dense sources.
Wind turbines have developed greatly in recent decades, solar photovoltaic technology is much more efficient, and there are improved prospects of harnessing the energy in tides and waves.
A fuller account of EROI in electricity generation is in the information paper on Energy Return on Investment.
The (WEO2016) makes the points that VRE have five technical properties that make them distinct from more traditional forms of power generation.