You are misreading that number. It's not years, it's how much energy is returned compared to invested. i.e. 6.5 times as much energy returned as invested over the entire life of the device.
For comparison hydrocarbon fuels have numbers in the 30 range, and nuclear is 60 and up (depending on how long the plant lasts). So 6.5 is quite poor. And they list no numbers on expected lifespan - lifespan is the number one thing that controls the EROI on solar.
Also, these numbers usually use very sunny areas and ideal angles to calculate the return. In Germany the results will be much worse.
You sure I'm reading that number wrong? EROI=6.5, expected panel lifetime 30 years => 30/6.5=4.6 years to earn back the energy required to create the panel. Expected panel lifetime of 20 years gives a payback time of 3 years.
For instance, panel lifetime of 20 years and EROI of 1 would give your number, 20 years, to pay back the energy required to produce one panel. Regardless, your original claim of 20 years to get back the original energy investment is greatly exaggerated.
If the EROI is indeed 6.5 then yes you are correct.
But last time I looked at EROI they always cherry picked the best results. (Bright sun, perfect angle, clean new panels, etc.) They also usually ignored installation costs (inverter, wires, framework). Additionally as the cells age they produce less energy.
In more typical installations the number I remember was 20 years after including everything. Although it you told me it was really 10 years I wouldn't argue much.
Under 5 years seems unlikely to me. I'll tell you how I know:
Market forces. With a ROI (not EROI - but obviously they are strongly related) of under 5 years you will have people installing the panels as an investment, with no subsidies needed. Yet you don't see that happening, and I suspect it's because the ROI is worse than 5 years.
This is a bit of a backward argument of course, but the fact that you need subsidies to get people to install solar panels tell me the ROI is not good enough.
I would support subsidies only for one purpose: To initially stimulate the market, in order that scale would reduce prices long term. But subsidies long term are wrong.
I agree with you that if you only get an EROI of 6.5, that's in itself just barely worth it. But to be fair, things are changing really fast. The United States has just added import taxes on Chinese solar panels, to prop up the US solar industry, from 30 to 250 percent depending on the manufacturer. This seems to me a really obvious sign that solar cells are getting a _lot_ cheaper. This might or might not change the energy question, but the economic viability of solar cells is getting better. Can't find the source on this, but I read somewhere that the newest Chinese solar panels are clearly economically viable even without subsidies.
Thats an overly useless calculation. The whole point of this exercise is: not all energy is created equal. You can waste many many millions of kWh of Norways free power and then ship the panel to Germany where it will replace energy generated through coal or nuclear. It might not make up for the energy you wasted back in Norway, but that was never the point to begin with.
I mean if you have free power, then yes converting it into something else even inefficiently is good. But what free power?
I know there are some geothermal plants in Iceland that capture otherwise wasted power and use it to refine aluminium, but I've never heard of countries with free power.
Norway generates 99 percent of its power through hydroelectricity. Its power is free in that there's no CO2 involved and no fossil fuels. Of course its not free; there's more to electricity than just generating it, but the prices seem cheap enough that the per capital consumption is three times that of other European states.
Norway happens to be a large producer of solar panels, too, so this example is pretty spot on.
No, because, as has been pointed out to you in another branch of this discussion, it is actually economically reasonable to build a solar cell that will yield more power than you put into building it.
Seriously dude, get over your obsession about solar panels and accept the fact that you simply didn't have your facts straight.
For comparison hydrocarbon fuels have numbers in the 30 range, and nuclear is 60 and up (depending on how long the plant lasts). So 6.5 is quite poor. And they list no numbers on expected lifespan - lifespan is the number one thing that controls the EROI on solar.
Also, these numbers usually use very sunny areas and ideal angles to calculate the return. In Germany the results will be much worse.