[Solstinox]

Growth is fueled by energy. If we're not exponentially growing it's because energy is a limiting factor for some reason.

I find the table in the middle of this page illuminating:

https://en.wikipedia.org/wiki/Energy_return_on_investment

If you were to map human population growth against the energy technologies in the table, you would basically see that human population growth bursts with jumps in EROI.

There are a couple of elephants in the room on that table that warrant some discussion.

One is nuclear: the massive jump in EROI it provides and our comparative hesitant/tepid adoption of it.

The other is a lot of the renewables: the massive leap backwards they offer.

[cornholio]

> Growth is fueled by energy.

No, growth is a an economic concept that expresses our consumption in monetary terms. We could consume anything: 1 million $ worth of electricity is perfectly equivalent, as far as GDP growth is concerned, with a 1 million $ painting that requires 100Wh to make.

Coming from an energy, food and housing starved world, of course our growth seems to be energy driven, because that's what people will consume first when they acquire wealth. But there are strong diminishing returns, you only can eat so much and keep tidy so much floor space.

In fact, the substantial housing cost bubble in the Western world, far above the greenfield costs of new construction with similar comfort, suggests we already are not pricing the house itself, rather the abstract values it comes with, such as the surrounding community, available schools and jobs etc. There is no practical limit to the subjective value of these, and they don't need energy to inflate in relative value.

[baq]

I'm pro-nuclear but reality is you can commission, operate and decommission a PV farm or a wind farm in less time than it takes to build and start a nuclear reactor. Excessive regulation is the reason, but it exists for a reason, too, and that reason isn't ecoterrorists, it's a rational fear that a major ef-up will make a piece of any country inhospitable for all intents and purposes forever.

[TheOtherHobbes]

For some reason I'm disinclined to trust a table that has "failed verification" next to almost every entry.

Besides - EROI is almost completely irrelevant compared to more obviously useful metrics like cost per kilowatt hour.

YMMV, but it's clear that renewables have the potential to offer very, very cheap and reliable energy.

Someone always points out that wind is intermittent, but renewables currently have almost no storage, and oil isn't any less intermittent - as almost every major geopolitical event since the 1970s oil crisis proves. See also, what's happening in the Red Sea.

Nukes? There's a reason that the recent string of coups in Africa has concentrated on uranium producing countries.

The real reasons for hostility to renewables are political. If there's a robust wide smart grid for distribution, and everyone has PVs on their roof, the fossil and nuclear BigCos no longer have a monopoly on supply. They also lose the political leverage that goes with it.

The fossil industry makes around $4tn a year in profits, and receives around $7tn a year in global government subsidies. That is a huge drain on the planetary economy, and a global renewables program would cut that by quite a bit.

[jillesvangurp]

We have a nice fusion plant called the sun. Almost everything we do is powered by it directly or indirectly. Tapping into its power more efficiently is what is driving economic growth this century.

Nuclear has one big problem. It's just way too expensive. Not just a little bit but by orders of magnitude. That's why renewables are outgrowing nuclear by an order of magnitude as well. We're talking pitiful amounts of nuclear here and there (mostly China actually) and a sweet 0.6-0.7 TW of new renewable capacity added every year, growing year on year. That should cross the TW mark some time later this decade just by virtue of current investment levels (which are also growing).

In comparison, there currently are plans for about 110 GW or so new nuclear capacity. Mostly in China. That's a total, spread over the next few decades. Per year it probably will average around 10-20 GW added per year. That's about 2 orders of magnitude off. And before you consider the existing nuclear capacity that will reach end of life during the same period. Nuclear capacity might actually start experience negative growth (i.e. shrink). And of course some those plans might actually be shelved. A lot can happen in a few decades. Like the addition of tens of TW of new renewable capacity making nuclear kind of redundant. Those nuclear plans date back to an age when people were severely underestimating how much renewables we'd have by now.

Even if you'd double or triple that amount of nuclear, it would still be a side show. The main economic driver for economies this century will be energy delivered mostly by wind, solar, and batteries and a long tail of other, more costly solutions like nuclear, hydro, geothermal. Unless something happens on the cost front, that's how it is playing out.

[sottol]

In my opinion economic growth is mostly fueled and sustained by population growth. And population growth depends on various societal, industrial and scientific advancements that often also coincide with EROI improvements.

Would our society look so different if 90% of our energy needs would be produced by nuclear? Would energy be cheaper?

[empath-nirvana]

https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...

Even if we use 100% free renewable energy with theoretically maximally efficient engines, at some point we will boil the oceans from just waste heat, as long as exponential growth in energy use continues.

[orwin]

Real GDP per habitant is fueled by energy usage (except for a short period in the 70s where it was fueled by increased efficiencies, at least in France).

[ZeroGravitas]

> The other is a lot of the renewables: the massive leap backwards they offer.

EROI is bullshit. But regardless, renewables score higher on this score than fossil fuels.

https://radar.brookes.ac.uk/radar/file/5ecefeb6-51e5-4aa3-a0...

> The lack of methodological consistency, however, among these papers has led to a situation where inappropriate comparisons are being made across technologies. In this paper we provide both a literature review and harmonization of EROI values to provide accurate comparisons of EROIs across both thermal fuels and electricity producing technologies. Most importantly, the authors advocate for the use of point-of-use EROIs rather than point-of-extraction EROIs as the energy “cost” of the processes to get most thermal fuels from extraction to point of use drastically lowers their EROI. The main results indicate that PV, wind and hydropower have EROIs at or above ten while the EROIs for thermal fuels vary significantly, with that for petroleum oil notably below ten.

[jamager]

leap backwards?

[Solstinox]

Wind-based energy tends to be par or worse than fossil fuels in terms of energy return on investment.

Photovoltaics are more grim depending on whose numbers you pull.

Right now nuclear is the only energy source we have that could sustain growth and be more environmentally friendly than fossil fuels.

If we want growth. And this is not to say we should only have one energy source by any means.

[floatrock]

Bravo on pointing out growth is dependent on energy -- we don't care about our exponentially growing economic debt because it doesn't matter as long as The Economy is growing exponentially, but if growth is tied to energy, that means we need to be exponentially growing our energy supply too.

Awesome job bringing in EROI. We can keep exponentially growing our energy supply as long as we have infinite reserves of high-return energy supplies.

Let's take a look at oil from your link:

> The weighted average standard EROI of all oil liquids (including coal-to-liquids, gas-to-liquids, biofuels, etc.) is expected to decrease from 44.4 in 1950 to a plateau of 6.7 in 2050

Huh, in EROI-speak, that means we're expending more effort to get fewer returns out, which is a fancy way of saying "Oil's getting tapped out"

Shale revolution?

> Resulting EROI is typically around 1.4-1.5

Anything above 1.0 is worth doing, but the Revolution sounds like bottom-of-the-barrel marginal returns.

So how about your incendiary renewables-massive-leap-backwards comment?

PV had admittedly a "depends on how you measure things" high error bars:

> mean harmonized EROIs between 8.7 and 34.2

Wind is quoted as 19.8 with front-of-the-technology-curve numbers quoted as high as 31. The nuance here is whereas oil has finite reserves and can only decrease long-term, manufacturing-based technologies will increase up the learning curve before they plateau.

So, finally we have nuclear: quoted as EROI 75-106. Clearly a winner on energy-return, but EROI doesn't capture the messy pragmatics. Instead of energy-return, we can look at cost-returns: Levelized Cost of Energy, or how much lifetime energy do you get out vs. the lifetime costs of that energy. And we all know how expensive nuclear plants are to design, build, and maintain. There have been nuclear plants shuttered because in the 10 years it would take to get them online, you could just overbuild solar way more cheaply. Big advantage of renewals is they're getting dirt-cheap (relatively speaking).

And I'm not even touching the politics of nuclear risk and waste yet... yes, there's solutions, but I would argue that's still a much hairier problem than renewables' intermittency.

Point is, yes, from a "exponentially-growing civilization requires exponentially-growing energy" point of view, nuclear is the only path forward. But cost-returns are just as important as energy-returns -- both can make a project infeasible, and if you consider both constraints, renewals aren't a bad solution.