Interesting chart, but it does not seem to consider the cost of the installation, just the fuel, or it seems to assume a very long amortization period for nuclear/fossil fuel generation plants.

With wind and solar, all you have is the plant. There's no EROEI on the fuel because there is no energy investment in the fuel for wind and solar.

For a very long time solar panels would cost more energy to manufacture than they would output through their lifetime. This is no longer the case, but the amortization period is still large.

Fuel is not the problem. The power plants are the problem.

They show the payoff period Germany and in Southern Europe. I wonder what the payoff period is in Texas.

It's probably better, but don't forget that this is inherently a global problem. Scotland is running 100% renewable - so what, who cares? Not only it's not enough (the country is small), they also import a lot of goods with manufacturing energy footprints that released co2 elsewhere.

Even if the US switches to 100% renewable the problem is far from solved. Look at the population pyramid of Nigeria, for example. Those people will want homes (cement, steel) and cars and flights.

I think I understand where you're coming from, but I would say 'don't let the perfect be the enemy of the good'.

Grand jumps in capability rarely (if ever) happen in the real world.

Gradual change can feel like a capitulation, but it's often the safest and best overall.

If you try to force huge change and fail or things go wrong or the system is deficient in some way, there can be a big backlash.

The CO2 released in production and deployment of solar cells is regrettable, but as soon as that solar cell comes online it starts displacing fossil fuel.

What is the significance of this?

Well you can do the maths.

Let's assume it takes 1 year to pay back the energy usage, on average, for the green projects (look up that Wikipedia link). Let's also assume that we can dedicate 5% of the world's energy budget towards new power plants and that the world stops growing. So: 5% energy recession and zero global energy demand growth. How long would that take to roll out? 1/5% = 20 years, all of those years will be of serious austerity. Multiple countries (especially those with "good", that is growing demographics) would blow up. Up to you to decide if it's feasible to execute, and those are very optimistic numbers. What if the energy usage grows at 2% and we can dedicate only 3%? Well, that would give us 1/(3% - 2%) = 100 years to finish the project.

These are not happy things to look at. Personally I'm just trying to avoid the impending climate doom. Whatever happens - this problem is here to stay with us for many decades.

That's some weird kind of fear mongering. You assume instant replacement of fossil fuel plants. If you don't do this, but keep them running, and add renewables on top, it looks different.

Using your numbers to demonstrate it of 1 year EROEI. Let's say we make a starting investment for one year where we take 5% of the world's energy output to invest into new renewable power. After that year is over, we have capacity to generate 5% of the world's energy output per year, but we don't replace any of the existing fossil plants, but put it to work for new energy plants. So the second year we spend that energy on another 5% of renewable energy. Now we have capacity of 10% of the world's energy budget at start of year 1. If we continue doing this, we have 20% after the third year, 40% after the fourth, and 80% after the fifth. By the end of the sixth year, we can generate 160% of the energy demand of the world at start of year 1. We can now turn off the fossil fuel plants and enjoy a 60% increase in energy output, most likely more than the world has grown in that time.

Now you wonder, won't it cost tons of money to use all of this energy to build new plants? Sure it will, but that's already priced into things. That's what we have banks for.

Your fears are unfounded.

You're right, I did not compound the green energy (or, as you say, assumed parallel termination of dirty plants). It would work if the world could collectively put aside 5% of the energy budget. Not sure if that's realistic, and also will there be enough commodities (though those are at multi decade lows in prices right now), but if so it should work.

Let's see how the world looks like post covid, as we're very likely to experience a huge "energy recession". Something that would be similar to that 5% energy austerity rule.

We have tons of unused capacity. Energy shortages would be indicated by high energy prices, but they are low. China had been building coal plants before actually having demand for them (creating a great place to mine BTC in the process), then expanded to build coal plants all over the world. The US is swamping international markets with fracking oil. In OPEC, the hate for each other still seems to be stronger than the desire to increase prices.

Nuclear is the answer.

You could start planning now and you would be lucky to get shovels in the ground by 2035.

France turned its whole grid nuclear in 15 years with 60s technology. The utter absurdity that has happened with nuclear energy is crazy. Its like the whole climate change disaster could have been avoided in the first place.

Nuclear is like anything else, if you build one bespoke reactor, its expensive. If you build 20 that are the same its gone end up cheap.

The problem is every country has its own government trying to build its own reactors and only have like one project going. Its like the rocket industry just 10x worse.

And the way regulation was managed after Three Mile Island was insane, and has utterly stopped nuclear innovation essentially impossible (specially new reactors) and makes nuclear building beyond expensive.

Its really a sad situation, humanity should be in the nuclear age right now. That we are still grappling with replacing coal power is beyond mind-blowing.

too true for most nuclear projects out there.

Well noted. Here's a paper: https://www.sciencedirect.com/science/article/abs/pii/S03605... The energy returned on invested, EROI, has been evaluated for typical power plants representing wind energy, photovoltaics, solar thermal, hydro, natural gas, biogas, coal and nuclear power. The strict exergy concept with no " primary energy weighting" , updated material databases, and updated technical procedures make it possible to directly compare the overall efficiency of those power plants on a uniform mathematical and physical basis. Pump storage systems, needed for solar and wind energy, have been included in the EROI so that the efficiency can be compared with an " unbuffered" scenario. The results show that nuclear, hydro, coal, and natural gas power systems (in this order) are one order of magnitude more effective than photovoltaics and wind power. =

Even if we assume that's correct, those sources have massive impacts under other categories. In contrast, anaerobic bacteria are terribly inefficient with their energy use, yet vastly outperform all animals in terms of biomass. So it's unclear to me that the EROI metric actually matters all that much. If I can produce solar panels with a solar-powered factory at a profit, I don't care about the price of coal or its EROI. I'm printing free money.

Of the 4 options you mention, I'm entirely a fan of hydro and nuclear. Especially nuclear. But FUD makes nuclear hard politically, so while I wouldn't campaign against it, I wouldn't waste my rep campaigning hard for it.

You can make while society falls around you. You want to make the most efficient use of time, energy, land, and materials. Why? So you can do more with it, give more people more time to think about things unrelated to survival, so you can support more people, whatever. Efficiency is key to civilization and progress. Solar takes 10X the land and 15x the material with no plan to deal with it after it has reached the end of life. Wind is worse.

I see what you're saying, but if you're arguing for advancement of civilization, then carbon should be priced accordingly.

End-of-life for solar is still a young field, but maturing rapidly. Regulations are already being formed in the US at a federal level. I guess gas plants can just close the well. But worst case,solar panels are small and can be buried (after we deal with the cadmium telluride)

I agree with end-of-life for wind though, not sure how it's gonna paly out.

What gets my goat is people don't bat an eye for granite countertops at home for 20-25k, but then solar roofs or battery storage is considered an expense.

Seriously? Trying to fearmonger what as dangerous crystaline silicon and fiberglass materials lying around? There are natural minerals more dangerous out there without disposal plans.

> Solar takes 10X the land and 15x the material with no plan to deal with it after it has reached the end of life.

Where solar in this case is photovoltaics/li-ion batteries and not CSP/molten salt?

edit: nvm see what they say here, not really impressed with a few of their assumptions of a optimal system, and using SEGS[0] is probably the worst one they could consider. Doesn't help that CSP tech is still in it's nascent stages compared to Nuclear,Hydro, Coal, and alot of system assumtioms for transmission are applied to CSP from them where CSP has other ways it can achieve even higher efficiencies with lower line losses (i.e. vacuum storage of molten salts and moving that to local grids to use in DSG systems) as well as being from 2013 (a lot more efficient systems have come online and global CSP capacity has doubled from 2013 to 2019).

"Only one work [30] has been found that provides values for invested energy and materials for different CSP technologies in a sufficient manner. The study which is part of a report from the German Centre for Aerospace (Deutsches Zentrum für Luft- und Raumfahrt) is a life cycle assessment for a hypothetical plant called “Sokrates”. Three different techniques were analyzed: Parabolic through with phenyl (SEGS) or steam (DSG) as coolant and a steamcooled Fresnel power plant, whose plane mirrors are roughly arranged to big parabolic mirrors. Plane mirrors are easier to manufacture and maintain, but have a lower concentration capability compared to parabolic mirrors, reducing the plant’s efficiency. Extremely high temperatures will reduce heat transportation, which also reduces the efficiency.

To achieve the high solar concentration, relatively big parts (mirrors) are necessary which are only usable in big plants. Therefore, due to economical aspects small or even individual plants are never considered. It should further be mentioned that, contrary to photovoltaics, the output of a CSP plant is not a linear function of the solar radiation intensity, so that only a deployment in sunbelt regions is in an economical scope. For regions with lower solar radiation like Germany this means additional power trans- portation energy demands and energy losses. The results shown in Table 4 are only for SEGS and Fresnel type technique, DSG is not tested yet. The location was assumed to be Ain Beni Mathar (Marocco, 34.17 N, 2.12 W) with a solar radiation constant of 2340 kWh/m2. The plant size is scaled to an annual output of 145 GWh (525 TJ), or 15,660 TJ over its adopted 30 year lifetime.

The higher demand for maintaining SEGS is caused by coolant losses due to the dominant phenyl energy inventory. The energy demand does not include the efforts for daily energy storage to provide electricity in the night hours, which is not possible with steam coolant as used by SEGS. The estimations for mirror replacements are very optimistic, doubling this rate will reduce the EROI by 20%, so the given values are the upper limit. Another significant reduction of roughly 30% (buffered) occurs when connecting this CSP plant to the European grid instead of using the output nearby the plant due to the very large copper demand.

It should be mentioned that the authors of the report [30] subtracted the phenyl maintaining demand from the output rather than adding it to the demand which can only be done if the used phenyls are directly produced by the CSP plant, on its site (see Sec. 5). This is not possible with the described CSP plant and would lead to wrong EROIs, making it infinite if all energy inputs are subtracted. Further corrections due to material inventory corrections lead to EROIs given in Table 4."[1]

[0] https://en.wikipedia.org/wiki/Solar_Energy_Generating_System...

[1] https://sci-hub.uno/10.1016/j.energy.2013.01.029