i appreciate the link to the fraunhofer slides!

— cartelization —

> Sorry, [the price-fixing cartel] is most likely not true and an unbased claim.

the price rises for the next two years were pre-announced at davos in january 02019 by eric luo, president of gcl, a top-ten chinese solar-panel company; this is a sort of announcement that cannot happen in a competitive market https://www.reuters.com/article/us-davos-meeting-solar-gcl-i...

after several years of record new low price ppas being announced every month or two, prices then held steady from 02018 levels until last year. you can see ppa prices in the usa at https://emp.lbl.gov/pv-ppa-prices and historical wholesale solar prices at https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... (this is the same pvxchange data you linked, but with data going back 7 years instead of one year, and i have archived their older data going back to 02009)

here you can clearly see that prices didn't improve from their 02018 level until the covid pandemic in 02020, but then recovered to the price-fixing level in mid-02021. they actually rose in 02023 and then returned to the price-fixing level in mid-02023, 4½ years after the cartel was announced at davos. the 02009–02018 trend was a fairly steady, continuous drop of 24% per year, faster than the longer-term average of 10%, largely because the doubling time of cumulative installed capacity had dropped significantly

if that 10% long-term average had continued from 02018 until today, five years, we would have expected a 44% drop in prices from 02018 to now. if the 25% average over 02009–02018 had instead continued, we would expect a 79% drop. the end-of-02018 price was €0.18 for low-cost panels; now it's €0.08, a 56% drop, which is an average yearly price drop of 14%. it's just that the cartel was able to delay the price drop for almost five years, and now it has more or less returned to the trend.

note that during the four-year period of artificially high prices the usa's shameless claims of overcapacity and dumping continued unabated and in fact dramatically escalated, culminating in trump's very punitive tariffs. that (plus reading the department of commerce's public filings) is why i don't consider yellen a credible source

— the experience curve —

> To explain this kind of price drop based on the history scaling laws (24.4% per doubling) would require the total production capacity (and installation) to have more than quadrupled over the last year.

not over the last year; rather, since the end of 02018

as it happens, cumulative pv installations in 02018 had reached almost 500 gigawatts (https://en.wikipedia.org/wiki/Growth_of_photovoltaics#Growth... or the fraunhofer slides you linked, slide 15) and in 02023 1600 gigawatts (https://iea-pvps.org/snapshot-reports/snapshot-2024/ or the fraunhofer slides) with an expected 655 gigawatts installed this year (https://www.pv-tech.org/bnef-global-solar-additions-655gwdc-...), which would mean about 1900 gigawatts installed right now if we interpolate linearly, almost but not quite the quadrupling you were looking for

but that's not actually enough! to explain the 56% price drop with fraunhofer's learning rate of 24.4% per doubling, you'd need 2.9 doublings, an increase in cumulative product manufactured of a factor of about 7.5, which is indeed technically 'more than quadrupling' but actually a lot more than quadrupling. since we've only had 1.9 doublings instead of 2.9, we should only see a 42% price drop, so the real price should be €0.11 per watt rather than €0.08. if we instead use the 20.2% learning rate from this plot of swanson's law https://en.wikipedia.org/wiki/Swanson%27s_law#/media/File:19... we should expect to see only a 36% price drop down to €0.12 per watt. so maybe there is some 'dumping of oversupply' going on, in the sense of selling off product at a loss

the learning rate required to explain a 56% price drop in only 1.9 doublings would be 35%, which seems implausibly high

the slide 50 you cite is apparently tracking a slightly different price than the low-cost solarserver numbers i've been tracking; it shows prices rising from 02020 to 02022, and the 02023 price as being about 50% below the trend line (roughly €0.20 rather than €0.30 per peak watt), much as the 02006–02010 prices are about 50% above it. so i can see how you'd come to a different conclusion from those divergent data

— the 12-year-long trade war —

> There was no recent transition into "mainstream". The scaling has been taking place for decades already and nothing was "held steady" for 12 years

what's happened for 12 years, and i'm sorry this wasn't clear from my previous comment, is that politicians in the usa have been making absurdly indefensible claims of 'overcapacity and dumping' to justify blatant protectionist policies that violate wto rules, prolong the energy crisis, promote global warming, strangle usa heavy industry, and undermine the usa's access to overseas markets, all in order to subsidize fossil-fuel production, the stranded assets of electrical utilities, and uncompetitive domestic solar panel production

(what i actually said was 'the usa has been pushing this overcapacity/dumping nonsense for 12 years now', and i am mystified as to how you could have misinterpreted that to mean that scaling has not been taking place for decades)

— crossing the chasm —

what i meant by the transition into the mainstream is that solar power is now a mainstream source of power rather than a form of environmental activism, an r&d expense, or a niche solution for remote cabins and communication satellites. this happened around 02018, but even today you'll find people arguing against it on the spurious basis that if it were net energy positive the power grid would already be running on it, so it's only sustained by subsidies

it's true that, if you look at log-log plots of solar growth over 40 years, it looks like a smooth exponential, with no obvious change of long-term growth regime. but that's exactly what it looks like for an innovation to successfully 'cross the chasm' into mainstream adoption. if you look at the log-log plots of adoption of innovations like desktop linux, segway, iridium, google glass, oculus, or nuclear power, they look exactly like that—until the point where they suddenly stop, without penetrating beyond rogers's 'early adopters' (worth noting: rogers doesn't believe there's a discontinuous 'chasm' but rather continuous risk of failure). but solar energy has now become firmly mainstream, so its growth has continued