Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Energy

blog.samaltman.com

Post reply on HN
Print view View original

71–80 of 287 posts

Re: Energy

#71

Post by JoeAltmaier »

DennisP wrote: post #55
beat wrote: post #20

I suspect solar (including wind/biomass) + batteries is going to trounce fission reactors in the not terribly long term. If you think of finance in terms of latency/bandwidth (a model I use for lots of things), reactors are high latency - they're expensive and take a long time to set up. Meanwhile, solar/wind is heading toward dirt cheap and trivial to set up. Environmental impact is minimal, too. It doesn't require…

Gigawatt-scale nuclear reactors take a long time. Ycombinator is investing in factory-produced reactors that fit in a truck. There are quite a few other companies working on small factory-produced reactors. Solar with batteries is a lot more expensive than solar alone. Solar is doing well right now with natural gas backup, but a lot of us would like to avoid fossil entirely. Solar with nuclear backup might be a great…

Confused: if you have nuclear, skip the solar and save money?

Re: Energy

#72

Post by Retric »

hyperpallium wrote: post #51

I wonder what environmental impact truly large-scale solar energy will have. In that it is moving energy away from where it would usually fall on the ground/plants, thus reducing heat, less rising air, less photosynthesis etc. Perhaps additionally aid global cooling? Though that energy will mostly end up as heat anyway. (Of course it's far better for the environment than present coal/petrol/gas/wood, and their energy…

As a sanity check, the earth gets ~1366 W/m2 * (6,371 km) ^2 * pi = 1.7e17 watts * 24h/day * 365.2425day/year ~= 1.5e21Wh/year ~= 1,500,000,000 terawatt hours/year. Humans use 155,505 terawatt-hour / year or ~ 1/10,000th of that much energy. (https://en.wikipedia.org/wiki/World_energy_consumption)

Further, it's all (99.99%) going to get released so net impact is going to be very local.

PS: In the end the real change would simply be changing the albino of the planet slightly. But, buildings and roads already cover far more land than solar is expected to anytime soon with minimal impact.

Re: Energy

#74

Post by andy_ppp »

DennisP wrote: post #40
andy_ppp wrote: post #26

Isn't decommissioning nuclear power plants still basically a huge bill underwritten by the tax payer? I'm not really sure about creating radioactive waste that has such huge half lives... From Wikipedia: Of particular concern in nuclear waste management are two long-lived fission products, Tc-99 (half-life 220,000 years) and I-129 (half-life 15.7 million years), which dominate spent fuel radioactivity after a few tho…

Nuclear power plants in the U.S. pay a fee for waste disposal. Those fees have accumulated in a fund, currently amounting to over $30 billion. The money was going to go to Yucca Mountain, until that project was shut down. The long-lived fission products are a very small portion of the total waste, and if we only had fission products to worry about, the total waste would go back to the radioactivity of the original or…

I really hope it's more than £30bn. No-one seems to know how much it costs to decommission one, but a link above says "range from $280-$612 million." Ouch.

Re: Energy

#75

Post by DennisP »

jarvist wrote: post #16
cjensen wrote: post #9

Earlier quoted context omitted.

Fusion and Fission systems tend to run 24/7, unlike Wind and Solar. There is far less need to store energy when using the former types of generation.

Fission: Nuclear power stations have relatively low capacity factors (a measurement of how much of time they're actually connected to the grid and producing power). This is typically 70% over the last few decades for Western countries (i.e. a third of the time, a nuclear power station is not producing anything). As well as unintended maintenance shut down periods, most reactor designs require a multi-month shut down…

Do you mean to include the entire U.S. as one of those states? Wikipedia lists nuclear's capacity factor as 90.3% in the U.S. in 2009, and 88.7% averaged over 2006-2012, according to the DOE: https://en.wikipedia.org/wiki/Capacity_factor#United_States

The Helion design which Ycombinator funds is pulsed, so sustained burn time isn't applicable. It's also much smaller and cheaper than mainstream tokamaks.

Re: Energy

#76

Post by [deleted] »

Retric wrote: post #72
hyperpallium wrote: post #51

I wonder what environmental impact truly large-scale solar energy will have. In that it is moving energy away from where it would usually fall on the ground/plants, thus reducing heat, less rising air, less photosynthesis etc. Perhaps additionally aid global cooling? Though that energy will mostly end up as heat anyway. (Of course it's far better for the environment than present coal/petrol/gas/wood, and their energy…

As a sanity check, the earth gets ~1366 W/m2 * (6,371 km) ^2 * pi = 1.7e17 watts * 24h/day * 365.2425day/year ~= 1.5e21Wh/year ~= 1,500,000,000 terawatt hours/year. Humans use 155,505 terawatt-hour / year or ~ 1/10,000th of that much energy. ( https://en.wikipedia.org/wiki/World_energy_consumption ) Further, it's all (99.99%) going to get released so net impact is going to be very local. PS: In the end the real chang…

[deleted]

Re: Energy

#77

Post by mikeash »

jarvist wrote: post #49
mikeash wrote: post #34

Earlier quoted context omitted.

Much of the waste problem can be solved by using reactors designed to use the waste as fuel. This isn't currently done, but there's no big technical reason it couldn't be. For what remains after that, well, there's nothing particularly wrong with sticking it in some extremely sturdy armored containers, sticking the containers in a shed, surrounding the shed with a razor-wire fence, and stationing a couple of guards a…

> using reactors designed to use the waste as fuel What do you mean? The waste is full of nuclear poisons (a technical term, isotopes that stop fission by neutron capture). Reusing it means reprocessing to extract the Plutonium, which is burnable in a reactor (particularly as MOX). The chemistry required for this is pretty messy, and the radioactive environment (fuel from a power station is very 'hot' radioactively s…

The main problem with reprocessing is fears of weapons proliferation, which is an odd fear when it happens in countries that already have large piles of nuclear weapons, but there we are. The waste is mostly still full of fuel. Advanced designs like the Waste Annihilating Molten Salt Reactor could make this simpler and cheaper.

What to do with the UK's plutonium seems obvious to me: use it as nuclear fuel. If this isn't being done it's presumably because of political opposition, not technical problems.

Re: Energy

#78

Post by rwcarlsen »

andy_ppp wrote: post #58
rwcarlsen wrote: post #43

Earlier quoted context omitted.

Power plants fund their own decommissioning [1]. And they also (in a way) already pay for disposal - a 1 mill per kWh fee on all energy generated payed to the federal govermnent in exchange for the feds taking responsibility for disposal [2]. This fee has been paid for decades - the industry has no problem supporting that level of disposal cost (and could even afford a higher fee if necessary). There has been an enor…

I'll counter your wikipedia links with the issues and costs associated with decommissioning in the UK: https://en.wikipedia.org/wiki/Nuclear_Decommissioning_Author... Current estimates for one Nuclear Power Plant Site (Sellafield): £114bn which seems A LOT!

Sellafield is a large site consisting of many facilities [1]. These include Magnox reactors [2] which were historically used to create weapons grade Plutonium and are much "messier" than typical commercial power reactors. The Sellafield site has been and is still home to a very large spent fuel reprocessing plant that handles spent fuel from numerous UK reactors. Reprocessing plants are an entirely different beast. And a lot of the activity at the Sellafield site is generally from older, messier technologies as well.

[1] https://en.wikipedia.org/wiki/Sellafield

[2] https://en.wikipedia.org/wiki/Magnox

Re: Energy

#79

Post by secstate »

Retric wrote: post #72
hyperpallium wrote: post #51

I wonder what environmental impact truly large-scale solar energy will have. In that it is moving energy away from where it would usually fall on the ground/plants, thus reducing heat, less rising air, less photosynthesis etc. Perhaps additionally aid global cooling? Though that energy will mostly end up as heat anyway. (Of course it's far better for the environment than present coal/petrol/gas/wood, and their energy…

As a sanity check, the earth gets ~1366 W/m2 * (6,371 km) ^2 * pi = 1.7e17 watts * 24h/day * 365.2425day/year ~= 1.5e21Wh/year ~= 1,500,000,000 terawatt hours/year. Humans use 155,505 terawatt-hour / year or ~ 1/10,000th of that much energy. ( https://en.wikipedia.org/wiki/World_energy_consumption ) Further, it's all (99.99%) going to get released so net impact is going to be very local. PS: In the end the real chang…

The problem here is that someone once did some cocktail napkin math with regards to dumping farm waste into the Chesapeake Bay and determined that the ocean is so enormous it was stupid to think some agro-waste would change much about it.

I can't find a source at the moment, my apologies. But suffice to say humans have a knack for considering their needs insignificant when in reality our Spaceship Earth looks ever more fragile the more we learn about it.

Re: Energy

#80

Post by DennisP »

JoeAltmaier wrote: post #71
DennisP wrote: post #55

Earlier quoted context omitted.

Gigawatt-scale nuclear reactors take a long time. Ycombinator is investing in factory-produced reactors that fit in a truck. There are quite a few other companies working on small factory-produced reactors. Solar with batteries is a lot more expensive than solar alone. Solar is doing well right now with natural gas backup, but a lot of us would like to avoid fossil entirely. Solar with nuclear backup might be a great…

Confused: if you have nuclear, skip the solar and save money?

Sure, if nuclear ends up cheaper per kWh than solar without backup.
Post reply on HN