Comment by dr_dshiv
1 year ago
Here is the graph of exponential installed solar capacity [1]. Like Moore’s law, continuous technological innovation and investment will be required to keep the pace. We just hit 1 terawatt— and doubling time seems to be about every 3 years. So… 1,2,4,8,16,32,64,128,512,1028, 2056 terawatts in 30 years?
With 20% capacity, that’s equivalent to >300,000 Million Tons of Oil (MToE) per year. Current global energy consumption is 14,000 MToE [2].
[1] https://ourworldindata.org/grapher/installed-solar-pv-capaci...
[2] https://en.wikipedia.org/wiki/World_energy_supply_and_consum...
That chart ends at 2022, but 2023 was an even bigger year than you would expect from that curve, with over 500GW of new solar installed. https://www.iea.org/reports/renewables-2023/executive-summar...
Also: “ In 2023, an estimated 96% of newly installed, utility-scale solar PV and onshore wind capacity had lower generation costs than new coal and natural gas plants. In addition, three-quarters of new wind and solar PV plants offered cheaper power than existing fossil fuel facilities.”
* That Wikipedia link gives an average global energy consumption of 4.810^12 watts (assuming 11.63 TWh per MToE). The solar insolation of Earth is about 210^17 watts The total power output of the Sun is about 410^26 watts. The total solar power output of the Milky Way galaxy is about 410^37 watts
Assuming exponential growth and assuming 20% utilization, that gives us
A fully solar economy in ~13 years * Kardashev Type 1 in ~59 years * Kardashev Type 2 in ~272 years * Kardashev Type 3 in ~381 years
Ahh, the classic case of seeing the bottom half of an S curve and projecting it out to infinite exponential growth.
The number of times things have experienced infinite exponential growth in all of history starting from the Big Bang: 0.
Nobody said "infinite".
The upper asymptote of an S-curve is often called its "carrying capacity". We expect an inflection point about halfway toward this point. What do you think the maximum capacity of global solar energy is? The total amount of solar energy hitting Earth is about 4.4 * 10^16 watts -- 44,000 Terawatts. If we covered 1% of the Earth in solar panels at a meager 10% efficiency, that's 44 Terawatts -- this is a reasonable low estimate for the "carrying capacity" from total solar irradiance. We're at about 1 Terawatt right now. A high estimate (remember, this is the absolute maximum) might be 10% of the Earth at 20% efficiency -- 880 Terawatts. Of course, if we run out of space on Earth, there's always more space in ... well, space.
Another "carrying capacity" could be the materials needed for production. As TFA illustrates, we have enough different ways of producing solar panels that we are not anywhere near maxing this out either.
So I think there's pretty good justification to think we're still at the very early part of this S-curve.
> 44,000 TW
Check your arithmetic; it's considerably more than that.
2 replies →
Sure, but until we see the inflection point we can't know how much longer the bottom half of the S curve lasts— it might be 2, 5, 10 years, or it might have already passed; either way we'll only know in retrospect.
Those different options make a big difference on how much PV is part of the long term global energy picture.
Ah the classic case of rounding a two digit number to infinity to make a strawman point?
Isn't the universe expanding exponentially since the Big Bang?
The expansion rate slowed down dramatically after the big bang and then sped up again, from Wikipedia:
> Cosmic expansion subsequently decelerated to much slower rates, until at around 9.8 billion years after the Big Bang (4 billion years ago) it began to gradually expand more quickly, and is still doing so.
/jk just wait long enough and that zero will go to Infinity
> So… 1,2,4,8,16,32,64,128,512,1028, 2056 terawatts in 30 years?
What did 256 terawatts ever do to you?
> So… 1,2,4,8,16,32,64,128,512,1028, 2056 terawatts
Ah, a power series.
This gives me hope! Thank you for sharing!
> So… 1,2,4,8,16,32,64,128,512,1028, 2056 terawatt
Multiplying by 2 is hard. Let's go shopping!