So what is sEROI anyway? Energy Return on Investment is a ratio of how much energy you can get out of an activity versus how much energy you put into that activity. Historically energy feedstocks change as depletion - or the consumption of that resource - results in depletion which typically alters the EROI over time. How does that happen? Well early oil wells produced 100 times the output for each energy unit consumed. In other words, for each gallon of fuel used to dig the well, you got back 100 gallons of oil.
Today the EROI ratio for oil is 15:1 a huge difference, and as oil depletes it will take more exploration, deeper wells and geographic challenges that will make energy in vs energy out converge towards 1:1
As a footnote to this topic, no modern civilization can expect to see economic growth with an EROI under 10:1. Stagnation, yes - growth no. De-growth as the ratio moves towards 1:1, with economic collapse occurring somewhere in between.
So that was EROI. sEROI is the broader reality of the system required to produce that energetic thing. Solar panels require mining, plasma deposition, conversion of metals into frames, wires and fastners. Then when they are no longer efficient, recycling the parts that can be. That is a total life cycle system. For solar panels that are analyzed in a ful;l life cycle which includes, creation, use and disposal - an "extended" EROI typically falls near or below 3:1. Consider batteries, grid buffering and back up plants that must come on when the sun isn't bright enough and you barely break even. Well below 3:1 which suggets that this is not a sustaining source, but a net energy sink. By the way the solar panel or wind system drives a mineral dependency that is 10 times greater than a fossil fuel energy source.
The often mis-used phrase of renewable is more aply described as re-buildable.
So solar PV extended EROIs look like 2:1 or maybe 3:1 in really favorable locations not the generated number from the finished good. Wind power may be as high as 7:1 but more typically 4:1 or 5:1.
So the take-away is: Oil is the whole economy. Green isn't very, and renewables are not. The real question I have for you and the world in general is, why are we not in a serious conservation mode? That is the only strategy that makes much sense to me.
As energy EROI continues its glide towards 1:1 also realize that long before you get there, the energy used to reinvest in making more energy will consume societal needs like infra-structure, road build, steel making and fixing bridges. Energy cannibalism will happen, as competition for the available BTUs increases. GDP will also decline with disproportionate impacts depending on where you are and which government you are a part of. This appears to be what's happening on a global scale right now.
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