Jevons paradox • Hacker News Board

Re: Jevons paradox

#161

Post by mitthrowaway2 » Wed, Jan 29, 2025, 9:38 PM UTC

aurareturn wrote: post #149

mitthrowaway2 wrote: post #146

Earlier quoted context omitted.

Jevons Paradox describes the situation where a 10x efficiency increase results in a >10x deployment of lumens, such that the amount of energy consumed for lightning increases relative to when lighting was inefficient.

Which has happened historically. Comparing this with the solid blue price line showing price indicates that the 100 fold fall in price per unit of light in the 20th century was due to increased efficiency, mainly as electricity replaced gas. Yet demand rose strongly over the period, increasing more than 100 fold. This challenges the view that increases in efficiency translate into reductions in demand, and thus emiss…

That's a good source, although that historical analysis extends to the year 2000 when even CFLs only had reached ~30% market share, and well before LED lighting hit mass adoption. It is only speculating about LEDs. There's no question that lighting demand has continued to grow but the efficiency increase has also been remarkable, so unless you know of another source that does the math, it's unclear to me to what extent it's ended up balancing out in this case.

Another confounder to Jevons' paradox is that the price of the input (electricity) can also change, independent of changes in efficiency. If electricity prices were to go up ten-fold during the switch to LED lighting, then we wouldn't expect much change in illumination (probably a net decrease, as people would be hurting so much from other electricity expenditures that they'd be hunting for any savings on their energy bill). That's of course a fictional scenario, but in the case of GPUs, well, they have been getting quite expensive.

Re: Jevons paradox

#162

Post by roenxi » Thu, Jan 30, 2025, 12:31 AM UTC

cjbgkagh wrote: post #78

roenxi wrote: post #70

Earlier quoted context omitted.

Couple of thousand dollars? Consultant turns up on site, gathers data, talks to a few people, sets up a model and solves it. Probably around a weeks work @ say $100/hr. Might be under-calling it for validation and there'll probably be some iteration to do so a project will take a few solves to complete + overheads.

The software is free, and few people even think about the hardware cost. But that’s not how it always was, it was a core part of Bill Gates world domination plan during the ‘foundation’ era (2008). Good ones used to be super expensive, then they were sold as excel plugins, and now Z3 is given away for free. And despite being free it’s still not used nearly as often as it should be, it’s not the algorithm or price hol…

Your point being? You're stringing together a bunch of observations without any argument relevant to Jevons' paradox.

My guess is that you're mistake is thinking something like [demand = 1/price]. That was never the prediction, the prediction is when efficiency improves, demand increases which is a pretty basic observation for most in-practice supply and demand curves (something like a Veblen good would be different). You're not talking about changes in demand and you're barely looking at efficiency beyond noticing that the price was positive and is now 0.

> And despite being free it’s still not used nearly as often as it should be ...

Case in point, if this wasn't obvious then you need to modify your expectations. Jevons' paradox predicts exactly this, because there are prices below free (ie, paying someone to use the thing) and we'd expect they eventuated people would find new uses for SMT solvers due to Jevons' paradox in context of a price signal that they were getting more efficient. That implies even at $0 in software costs we aren't going to be using them everywhere we could.

Re: Jevons paradox

#163

Post by omgwtfbyobbq » Thu, Jan 30, 2025, 4:08 AM UTC

FYI, people mix up Jevon's and the rebound effect.

https://en.m.wikipedia.org/wiki/Rebound_effect_(conservation...

The rebound effect is common (people have something more efficient and use it more, so the efficiency improvement is somewhat offset by more use), but Jevon's is relatively uncommon (people have something more efficient and the increase in use is large enough to offset the efficiency improvement and then some).

Re: Jevons paradox

#164

Post by blagie » Thu, Jan 30, 2025, 8:24 PM UTC

HarHarVeryFunny wrote: post #158

blagie wrote: post #117

Earlier quoted context omitted.

> Has the average homeowner added more ceiling lights or lamps because of different bulbs? As much as I appreciate the snark and sarcasm, at least where I live, the equivalent is happening. Old home and commercial construction would typically have one central light per room. Homes would have a single light fixture with 1-3 lightbulbs at the center of each ceiling and were pretty dimly lit. Commercial would be similar…

I can accept that new construction may have more lighting, but nowhere near 10x, and certainly not 10x overall when you factor "legacy locations" where it is mostly just a bulb replacement.

You can accept what you like.

I am describing where I live.

If you don't accept that a place like this might exist, without so much as a follow-up question, says more about you than anything else.

Re: Jevons paradox

#165

Post by HarHarVeryFunny » Thu, Jan 30, 2025, 9:13 PM UTC

blagie wrote: post #164

HarHarVeryFunny wrote: post #158

Earlier quoted context omitted.

I can accept that new construction may have more lighting, but nowhere near 10x, and certainly not 10x overall when you factor "legacy locations" where it is mostly just a bulb replacement.

You can accept what you like. I am describing where I live. If you don't accept that a place like this might exist, without so much as a follow-up question, says more about you than anything else.

Are you really claiming that a new home has 10x more lighting than an old one? Or are you just saying that your own house it lit up like a lighthouse - search lights in every room, perhaps?