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Comment by mchannon | Hacker News Reader

Solar and wind might surprise you. Anytime you're working on a rooftop or on a tower, your risk of falling to your death is not zero.

Hydro is in a special case too, because a sudden dam collapse could kill thousands of people in the blink of an eye. Johnstown Flood Disaster comes to mind. Whether you blame the collapse on the hydropower is another question.

Call me a crackpot, but I believe geothermal may be worse than the rest put together. By leaching the heat the earth needs to "lubricate" its plate tectonics, I think you might be delaying, amplifying, and shifting the focus of the earthquakes. I think our overdue Hayward earthquake is being influenced by the GWh of heat energy taken out at Salton Trough and the Geysers. Force is building up like in an engine you let the oil out of. I theorize we're about to find out what the Earth-scale equivalent of throwing a rod is.

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This is outside of my normal area of expertise, but from what I gather, the total geothermal power output was around 14 GWH in 2017 [1], with an estimated maximum of 2TW possible worldwide if we develop every spot available [2].

It looks like the current estimates of baseline power lost through plate tectonics from the mantle are 35-47 TW, "from secular cooling, internal radioactivity, and core heatflow across its base" [3,4]. To bring these numbers into scale, there is approximately 173,000 TW of heat energy bombarding the earth [5]. I am not able to find estimates for the total thermal energy stored in all of the earth, as there is decent debate about what the inner 'layers' are made of; however, it seems doubtful that we are making a large impact even on localized regions with a max current output of 14 GW when compared to the 35 TW per year lost naturally.

[1] https://www.iea.org/topics/renewables/geothermal/

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

[3] http://adsabs.harvard.edu/abs/2016AGUFMDI52A..02D

[4] https://www.quora.com/How-much-energy-is-stored-in-the-earth...

[5] https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget

Did you switch units from wh to w?

And in 1975, Banqiao Dam in China killed 26,000 people immediately from flooding, and another 145,000 in the aftermath, according to China's official estimate.

https://en.wikipedia.org/wiki/Banqiao_Dam

>Anytime you're working on a rooftop or on a tower, your risk of falling to your death is not zero.

Okay, but I'd still be interested in:

a) A measure of death risk to the general public, i.e. people not directly involved in the production of the energy. It's important to distinguish internalized vs externalized risk.

b) A measure that accounts for the potential cost of preventing these deaths. That is, one that could capture insights like "source X and source Y currently have the same death count per kWh, but it would cost half has much to achieve a 10% reduction in deaths from X compared to Y".

The ratio of internal/external deaths would hugely effect the measure in b) -- it's much easier to stack on measures that can prevent deaths if they're employees of the provider than if it's the general public.

And so, on a), I would guess that measure for wind power is really hard to distinguish from zero.

> A measure of death risk to the general public, i.e. people not directly involved in the production of the energy. It's important to distinguish internalized vs externalized risk.

That's kinda creepy. Like we should be ok with Appalachian coal mining's horrible safety record because the general public never dies in mining collapses or gets black lung. Who cares about some faraway people just so long as I can run my crypto farm at under 5¢/kWh?

Very "Hunger Games".

certainly shouldn’t be okay with it, but if arbitrary people in a 100km radius were effected rather than just miners, yes that would be worse, because their “decision” to remain in the area is further removed from the problem than the decision to remain a miner

So what are you thoughts on coastal cities? Should the government do something about them?

My memory is every so often a major hurricane comes along and kills a bunch of people. The people who die probably didn't choose to put the city where it is. The risks are much higher than the nuclear industry.

And some follow up questions, because I always vent on Nuclear (sorry, don't mean to take it out on you, the lack of evidence based policy on environmental issues just gets me every time):

Is dying in a hurricane better than the health impacts of nuclear, which are many years delayed?

Do you think that the evacuation from the region around Fukashima (deaths: 10s of people), which killed more people than the radiation (deaths: 0) is evidence that the standard of "were effected" is too high?

Have you ever exposed yourself to so much solar radiation that you felt heat on your skin? Do you feel that this level of risk is remotely acceptable, given the number of deaths caused by skin cancer each year?

_PS_ I've worked on a coal mine. Deaths mining coal is already a crazy low figure, Australian coal mines are probably safer than supermarkets by the statistics. I'd be shocked if erecting and maintaining solar panels and wind turbines is safer than nuclear. Roofs and spinning blades will kill people.

>Call me a crackpot, but I believe geothermal may be worse than the rest put together. By leaching the heat the earth needs to "lubricate" its plate tectonics, I think you might be delaying, amplifying, and shifting the focus of the earthquakes.

I cannot imagine that we are anywhere close to technologically capable of having even a miniscule impact on plate tectonics.

That's similar to what the fracking advocates said before they started causing earthquakes.

Causing earthquakes is easy (I lived close to a mine, and earthquakes happened). Affecting plate tectonics ... I feel like that is something entirely different.

Interesting. Trade “the planet’s climate” for “plate tectonics” and you’ll find a lot of like-minded Americans, particularly in Congress.

The Earth's crust has something like a million times the mass of its atmosphere.

Actually, TIL (a google search revealed) it's only 5 times more massive.

That is not correct either.

Earth's crust: 2.77 * 10^22 kg

http://adsabs.harvard.edu/abs/2007AGUFM.V33A1161P

Earth's atmosphere: 5.15 * 10^18 kg

https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Density_an...

The crust is about five thousand times more massive.

The factor of 1000 difference is what you get when you accidentally forget to convert between kg and tonnes.

5000 it is.

The mass of the atmosphere is same as mass of 10m layer of water (because they both create 1 atm hydrostatic pressure). Obviously, the crust is much thicker than 10m, also much denser than 1000kg/m^3.

I do agree it seems like a bad idea to leach heat from the inner surface of earth in large quantities. I actually feel the same way about wind as well (a bad idea to take enormous amounts of energy out of the weather system before understanding it).

What about solar? Change an area of land that previously reflected most of the light back into space to absorb it instead.

Technically you don’t take it out. You just move the energy somewhere else. It all ends up back as heat eventually. We already move vast quantities of energy around with our food production and distribution systems.

Lubricating these faults often has the reverse effect; it allows the plates to constantly slip and having more frequent, smaller earthquakes. That being said, the geysers quake a few years back hit the theoretical maximum for that portion of the fault so who really knows. See below for info on the topic as well as the Parkfield Experiment.

https://earthquake.usgs.gov/research/parkfield/fluids.php

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