Geothermal Power in the North Bay | Hacker News Reader

Geothermal Power in the North Bay

blog.jonudell.net

48 pointsrbanffy17 comments

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> It accounts for 20% of California’s renewable energy.

That doesn't sound right. It seems to come from Wikipedia with a 2019 date, but even then:

The Geysers produced 5,543 GWh in 2022 [1].

California generation from renewables:

2019: 64,336 GWh [2]

2023: 76,153 GWh [3]

[1] https://geysers.com/The-Geysers/Geysers-By-The-Numbers

[2] https://www.energy.ca.gov/data-reports/energy-almanac/califo...

[3] https://www.energy.ca.gov/data-reports/energy-almanac/califo...

Maybe an old on-site plaque?

I had a fascinating conversation with someone that has been working on this system for the last 20 or so years.

Water treatment is powered by the geyser and in turn the leftover brown water feeds the geyser.

Pretty neat (for sewage)!

The joke about The Geysers is that it's California's "Brown Energy" because of the use of sewage for the steam generation.

Maybe this is a dumb question but is pumping sewage effluent into it as the water source a great idea?

Why not? The average reservoir steam temperature is well above boiling (370 F, 83 psi) so it's completely sterilized. In comparison, an autoclave used to sterilize surgical instruments (say) reaches 250 F.

Does not change your point, but an autoclave is also pressurized.

Ack, any temperatures above the boiling point of water at STP is going to require pressurization. Autoclaves are low pressure compared to this system.

One reason may be contaminants. Most sewage water has a lot of salts, proteins, weird minerals, heavy metals, etc. in it which can cause cause significant corrosion and other issues even at room temperature.

However, most geothermal systems already have issues with lots of salts and minerals being pulled from the surrounding rock (even with in-Situ water), to the point that maintaining equipment when things are constantly trying to dissolve and/or crystallize in them is one of the dominant costs.

So as long as the water is treated enough it doesn’t ‘cook’ into a gelatinous mass when it hits the hot rocks, it probably isn’t making the problem any worse.

If anything, I imagine the geothermal system could act to destroy otherwise hard to remove organics, like drug residues. Various dissolved metals and metal-rich surfaces could act as catalysts.

Some geothermal systems in the Salton Sea have had issues with deposition of metal sulfides, with the deposits being so rich in silver they are in effect high grade ores (including native silver metal). Unfortunately these weren't economical to extract, but they do act as artificial replicas of natural ore forming systems.

Folks in Santa Rosa used to have bumper stickers on their electric cars: "My car is powered by magma" or something like that.

How many AA batteries is that?

I suspect tongue in cheek - but - this seems funny to analyze.

I found an estimate for a typical AA batteries energy content as 4 watt-hours. (14.4 kj).

Rounding the energy output from ‘the geysers’ to 6 Terawatt hours (6000 gigawatt hours), means 1.5 trillion AA batteries per year, every year.

That’s a lot of battery changes! In fact, if someone went around doing nothing but changing batteries, 1 per second, 12 hours a day, 365 days a year, they’d need a staff of approximately 100,000 of those people to keep up.

I can see why it was more economical to do what they’re doing. Also, apparently only 4 billion AA batteries are made per year [https://www.sciencedirect.com/science/article/pii/S235197892...]

> That daily recharge is implicated in the region’s frequent small earthquakes. (But nobody seems too worried about that, and maybe it’s a good thing? Many small better than one big?)

See also: the 2019 Ridgecrest earthquakes whose epicenter was the Naval Air Weapons Station China Lake geothermal plant:

https://en.wikipedia.org/wiki/2019_Ridgecrest_earthquakes

https://news.usni.org/2019/07/09/california-earthquakes-leav...

https://www.openstreetmap.org/?mlat=35.766&mlon=-117.605&zoo... (Epicenter)

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

https://cosoenergy.com/

https://www.eia.gov/electricity/data/browser/#/plant/10874/?...

I've never heard any seismologist holding a responsible office blaming the Ridgecrest quake on any man-made cause. The links posted do not support that claim either.

Do you have any information which directly supports this?

Unclear in this situation, but fracking, petroleum extraction, and geothermal plants are implicated in earthquakes [https://news.stanford.edu/stories/2019/05/lessons-south-kore...] - depending on how it is done.

That was a Kaiju getting through the big dimensional portal. Made a lot of mess in the 24 seconds it took to subdue it.

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