What about
https://www.theguardian.com/environment/2019/oct/24/offshore-windfarms-can-provide-more-electricity-than-the-world-needs

"if windfarms were built across all useable sites which are no further than 60km (37 miles) off the coast, and where coastal waters are no deeper than 60 metres, they could generate 36,000 terawatt hours of renewable electricity a year. This would easily meeting the current global demand for electricity of 23,000 terawatt hours."

That's not counting
"The next generation of floating turbines capable of operating further from the shore could generate enough energy to meet the world’s total electricity demand 11 times over in 2040"

and not counting solar, and other 'renewables'.

I'm tempted to say, with relief and surprise, "job done".

It's said that earth's solar receipt is 90x our total current energy demand. It now appears that as an alternative to covering vast areas of desert with PV panels/mirrors etc, offshore wind may be an easier or less obtrusive way to capture that solar power - since all wind and weather is driven by the difference in insolation between equator and poles.

All (?) 'renewable' energy is different from burning fossil, and even nuclear to an extent - as the price per unit of electricity produced has no 'per unit' component in terms of cost or scarcity of fossil fuel or uranium delivered. Its cost per unit is just the fixed (i.e. not 'per unit') cost, overwhelmingly of writing-off the original capital expenditure, and minorly of maintenance - and of course there's profit.

Nuclear is an in-between case - the per-unit cost of uranium is dwarfed not only by the fixed writing-off of capex, but also of massive fixed costs of maintenance, safety, disposal of lethal by-product, and decommissioning.

Nuclear electricity was supposed to become "too cheap to meter" but in practice has gone in the other direction, due to the above costs, ever-increasing. However all (?) renewables exhibit an opposite trend - their technologies and fixed costs continue to plummet, no end in sight, so really do promise to become "too cheap to meter". It's called zero-marginal-cost production.

Now that such a massive over-supply potential is revealed, enough to supply the world's all-energy demand, not just electicity, the current wisdom that
yes, we can completely de-carbonise, but only if demand is reduced by 80%
goes out the window. No need to insulate the nation's building stock, transform industrial processes etc!

Nearly free energy available in glut opens up a raft of other energy-hungry green possibilities:

Electrolysis of sea water into hydrogen, ending the last justification of fossil fuel, for mobile power.

Distillation of sea water into fresh water, so we can stop draining earth's remaining aquifers (the fast-depleting stock of melt water from the last ice age), presently salinating by drawing in sea water to fill the voids - and limitless non-salinating irrigation, restoration and re-cooling of vast Saharasian forests, rivers and fertility.

Complete capture and recycling of the world's current stock of all materials, incl sea debris. The technology of automated sorting of different metals, plastics and rare-earths already exists. What's missing is the huge amount of energy required to break down chemical compounds, back to virgin feedstock.

Pulling CO2 out of the atmosphere, by whatever technology, bound to be energy-intensive.

These taken together are also key in ending the other elephant in the room - as well as the GHGs/decarbonisation/climate change issue, which has dominated green discourse - there's all the other kinds of pollution - chemical and bio-active electromagnetics. At last greenies can shift their focus to the latter.

Abunbdant energy is also likely to be needed to pull trace polutants out of the atmosphere and sea, and cleaning up same on-land.

All looks like good news to me.

Posted By: fostertomNow that such a massive over-supply potential is revealed, enough to supply the world's all-energy demand, not just electicity

You're forgetting one rather major factor - cost.

It's still the case that onshore wind and solar are cheaper than offshore wind, so you can't simply wish them away. Cheapest of all is hydropower, in places that have suitable locations.

Posted By: Peter_in_Hungarythe destabilisation of the economic and political (think tax revenue) markets that a quick uptake of (almost ) free energy would cause.

Surely you're not arguing for continuation of the fossil/nuclear status quo, or slowing down renewables' uptake, or artificially pricing them to not out-compete fossil/nuclear?

Posted By: Peter_in_HungaryMuch of the world economics is reliant on the petrodollar and turning that on its head IMO will cause massive disruption both economically and politically.

If the final un-rescueable 2008-style crash doesn't happen first. China is hell-bent on breaking up the petrodollar hegemony anyway.

OK - I can handle that!

In a world where all such old-world systems are teetering on the brink, the best we can do is elaborate visions of things that will work 'with the grain' i.e. in empathy with nature as the answer to pretty much everything, rather than conquering it. The future must be built on such things, as the old collapses.

Posted By: squowseThe problems are still the same though - storage and transmission.

I acknowledge storage as a potential problem, although I believe it's largely answered by long-distance interconnectors so local deficits and surfeits can be balanced out. Plus you can store a local excess by electrolysing hydrogen or any similar process, since in an 'energy is free' world you don't care about efficiency.

I don't understand what you think the problem with transmission is? I thought MV HVDC enabled continental scale transmission.

Also there is a human, environmental and carbon cost to this massive hypothetical construction project.

There's certainly a large financial cost, but given the aim is to save the planet, I'm not sure how relevant the other measures are?