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Sustainable Energy without the Hot Air (Revised, Community Edition)

climate.lifeitself.us

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Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#131

Post by pfdietz »

RobinL wrote: post #17
algo_trader wrote: post #2

Alas, this is probably pointless. Some technologies (PV, batteries, wind) have improved by an order of magnitude - and swamp out all other considerations. EDIT: to be clear, i loved the original book, and have re-read it several times over the years.

Pointless in what sense? The very reason I'd like to see it updated is to see whether the conclusions change materially when we take into account technological progress. As far as I understand it, whilst costs may be substantially lower that he envisaged, MacKay argued there are fundamental physical constraints on solar and wind that mean they still are unlikely to be able to provide all our energy needs (in the UK a…

If I recall correctly, he reached that conclusion by assuming a lot of biomass energy. Biomass is extremely inefficient at converting sunlight to usable energy (and burning biomass derived fuels in IC engines is very inefficient at converting that chemical energy to work.) PV + battery vehicles would drastically reduce the land area needed.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#132

Post by ben_w »

gnramires wrote: post #103
ben_w wrote: post #48

Earlier quoted context omitted.

On that timescale I expect us to engineer antimatter-based energy storage. Or do something literally incomprehensible — a thousand years ago we didn’t have the language to describe the language to describe relativity.

It doesn't quite work like that. 1000 years ago Europeans (you may say) only traveled routinely within 1 continent. Today, they travel routinely to all 7 continents. You can't say in another 1000 years anyone will travel to 14 continents -- there's only so much Earth to discover :) We can know Earth in better detail, but it's inherently limited. In the same vein, there's no guarantee we will continue to discover revo…

I get the point, I just don’t think we can justify that level of confidence.

We might be just about to reach a grand unified theory of everything and then science just becomes collecting butterflies or whatever that quote was; or it might turn out that uncovering dark energy reveals 10^80 new kinds of fundamental particles and a way to construct pocket universes we can engineer to extract Big Bang energy levels or dump equivalent levels of entropy.

I wouldn’t want to put money on which; and I say that as someone hopeful for life extension tech that would allow me to wait and find out.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#133

Post by pfdietz »

sdenton4 wrote: post #55
lucb1e wrote: post #20

Earlier quoted context omitted.

I wonder if this is correct. Setting the nuclear slider to max single-handedly reduces emissions by 30%, decreases energy costs rather than increases, does not require land use change, improves air quality, and also reduces electricity demand by using the waste heat for district heating. Now add: (1.) electrification of freight transport, (2.) tackling the (relatively) quick wins in industry electrification, and (3.)…

See also, peak uranium : https://en.m.wikipedia.org/wiki/Peak_uranium 2017 known supply is enough for 130 years at current usage (supplying about 10% of global energy). Each doubling of production halves the peak timeline. Basically no one expects discovery to outpace usage. So, at best, nuclear is a stop gap and part of a different long term solution. Which could be fine! But the extremely low LCOE and fast build ti…

> (supplying about 10% of global energy).

Current nuclear supplies 10% of global ELECTRICAL energy, not total energy. If you scale burner reactors to supply the 18 TW of primary energy demand the world uses, projected cheap uranium runs out rather quickly.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#134

Post by gnramires »

ben_w wrote: post #132
gnramires wrote: post #103

Earlier quoted context omitted.

It doesn't quite work like that. 1000 years ago Europeans (you may say) only traveled routinely within 1 continent. Today, they travel routinely to all 7 continents. You can't say in another 1000 years anyone will travel to 14 continents -- there's only so much Earth to discover :) We can know Earth in better detail, but it's inherently limited. In the same vein, there's no guarantee we will continue to discover revo…

I get the point, I just don’t think we can justify that level of confidence. We might be just about to reach a grand unified theory of everything and then science just becomes collecting butterflies or whatever that quote was; or it might turn out that uncovering dark energy reveals 10^80 new kinds of fundamental particles and a way to construct pocket universes we can engineer to extract Big Bang energy levels or du…

The thing is, we can't avoid putting money somewhere -- we are forced to make bets all the time (do nothing is also a bet). I would put the likelihood of pocket universes at something like 0.00000001% chance. Not zero, but really low.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#135

Post by pfdietz »

bbojan wrote: post #79
sdenton4 wrote: post #55

Earlier quoted context omitted.

See also, peak uranium : https://en.m.wikipedia.org/wiki/Peak_uranium 2017 known supply is enough for 130 years at current usage (supplying about 10% of global energy). Each doubling of production halves the peak timeline. Basically no one expects discovery to outpace usage. So, at best, nuclear is a stop gap and part of a different long term solution. Which could be fine! But the extremely low LCOE and fast build ti…

Current reactors (light and heavy water reactors) all use solid fuel, which is very inefficient due to use of once-through fuel cycle. Because xenon is the most common fission product, and it's a gas, the reaction must be stopped before all fuel is used, as otherwise the solid fuel pellets would crack. If you assume 3% enriched uranium (U-235) and 97% depleted uranium (U-238) (a typical fuel load), the fuel pellets a…

I thought fuel pellet cracking was already a tolerated thing. Pressure builds up in fuel rods due to escaped xenon and krypton.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#136

Post by zbrozek »

bluGill wrote: post #109
zbrozek wrote: post #80

Earlier quoted context omitted.

Most of the buses I see around here (Sunnyvale through San Mateo is my typical stomping ground) are either "not in service" or very nearly empty. I haven't taken a bay area bus in fifteen years. I routinely outpace them on a bicycle. I could imagine 8-15 passenger vans with on-demand routing would see much better utilization.

On demand routing cannot get 10 passengers per hour. The idea sounds good, but it has been tried and found slow and inefficient https://humantransit.org/2019/08/what-is-microtransit-for.ht... make sure you read his previous series that he links. ReaRead that, and then quit wasting everyone's time advocating a stupid idea that keeps coming bcback. Good transit advocacy should aim to get people to not drive.

The article talks a lot about coverage but not utilization. Searching the domain (I'm not going to read all of its content to narrowly search for something) doesn't surface much data or discussion of bus utilization.

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#137

Post by zbrozek »

KennyBlanken wrote: post #107
zbrozek wrote: post #80

Earlier quoted context omitted.

Most of the buses I see around here (Sunnyvale through San Mateo is my typical stomping ground) are either "not in service" or very nearly empty. I haven't taken a bay area bus in fifteen years. I routinely outpace them on a bicycle. I could imagine 8-15 passenger vans with on-demand routing would see much better utilization.

Your typical location might place you on the route bus drivers use to return to a depot or to get to the start of a popular route. Or the time you're out and about might coincide with when a large number of busses are coming into, or going out of, service. For example, if you work offset hours you'd easily see the pre or post rush hour ramp up/down traffic. Out of service busses also travel faster than in service one…

Those mitigating circumstances are good things to think about, but aren't applicable to my experience. If you've got hard data, please post it. I was unable to find utilization rates. Total ridership is easy to find, but not answering the questions at hand (utilization and uptime).

Re: Sustainable Energy without the Hot Air (Revised, Community Edition)

#138

Post by ben_w »

gnramires wrote: post #134
ben_w wrote: post #132

Earlier quoted context omitted.

I get the point, I just don’t think we can justify that level of confidence. We might be just about to reach a grand unified theory of everything and then science just becomes collecting butterflies or whatever that quote was; or it might turn out that uncovering dark energy reveals 10^80 new kinds of fundamental particles and a way to construct pocket universes we can engineer to extract Big Bang energy levels or du…

The thing is, we can't avoid putting money somewhere -- we are forced to make bets all the time (do nothing is also a bet). I would put the likelihood of pocket universes at something like 0.00000001% chance. Not zero, but really low.

Sure, but I wouldn’t make a 1000 year bet, nor accept that not making one in this particular case is itself a bet as the infrastructure we make today isn’t likely to still be around in even a third of that time.

All the stuff that I am currently in favour of for global energy supply and environment are mainly focused on the 50-100 year horizon for capability. I only care about longer timescales than that for damage on the grounds that kicking cans down the road seems both unfair and, given both how governments and civilisations fall, likely to make rebuilding unnecessarily difficult.

(I believe, but do not know, that this will change if we get radical life extension)

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