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downrightmike 3 days ago

They should just pave the mojave with solar panels. Nearly no one lives there and no one wants to live there and it is dead center to western states.

If China can pave mountains, a little desert with caliche should be easy

tjwebbnorfolk 3 days ago | parent | next [-]

As a rule, if you're tempted to begin any sentence with "they should just..." -- don't.

Electrical signal attenuation increases with the square of the distance, so you'll lose ~95% of the power to heat loss in the wires if you try to power Seattle from solar in Nevada -- not very eco-friendly, you'd agree? Also the extreme heat destroys solar panels. Also, dust. Also the permitting of stuff across state lines is so time-consuming it's effectively illegal.

There are a lot of very good reasons why we haven't covered the desert in solar panels.

agnokapathetic 3 days ago | parent | next [-]

> Electrical signal attenuation increases with the square of the distance

not true. in standard HV-AC lines, power losses are ~10% per megameter. HVDC gets to 3-5%. So Nevada to Seattle would be at most 20% loss, and in practice 15%, and with HVDC closer to 7%.

https://www.nationalgrid.com/sites/default/files/documents/1...

AnotherGoodName 3 days ago | parent | next [-]

I think the op must have been confused by the inverse square law for omnidirectional wireless transmission.

https://en.wikipedia.org/wiki/Inverse-square_law

This is where you picture an expanding wireless sphere of transmission from a point source and since the surface area of this sphere grows by the square of the distance you get this "power attenuates by the square of the distance" rule.

This of course doesn't apply to power over a 2D cable.

kulahan 3 days ago | parent | prev [-]

I have no dog in this fight, but this is so impressive it sounds wrong. I don’t think it is wrong, I’m just really blown away

yndoendo 3 days ago | parent [-]

"Taming the Sun: Innovations to Harness Solar Energy and Power the Planet" by Varun Sivaram [0] is a good source on ways to improve renewable energy from infrastructure design changes. He talks about the HVDC longitude runs that would improve transfer of electricity to areas that may be cloudy where it is sunny during peak.

My point of view with Tesla vs Edison is that they were both right and wrong under select circumstances.

[0] https://mitpress.mit.edu/9780262537070/taming-the-sun/

kulahan 3 days ago | parent [-]

Thanks, I’m looking forward to digging into this!

Aurornis 3 days ago | parent | prev | next [-]

> Electrical signal attenuation increases with the square of the distance

Power transmission lines at 60Hz primarily have ohmic losses, which are linear with length of the conductor.

Interesting fact - Power transmission lines are long enough that the capacitive and inductive effects do matter a little bit, even though it's only 60Hz. That's why spacing between conductors is important. 3-phase lines will also rotate the order of conductors every so often to keep the average spacing between all pairs of lines similar.

vizzier 3 days ago | parent [-]

The mind boggles at how many little bits of information like this keep our world running smoothly...

IncreasePosts 3 days ago | parent | prev | next [-]

I think you're over estimating losses for high voltage transmission lines. It's "only" 800 miles from the Mojave to seattle. In China there is a high voltage transmission line over 2000 miles long

strongpigeon 3 days ago | parent | prev | next [-]

> As a rule, if you're tempted to begin any sentence with "they should just..." -- don't.

Strongly agreed.

> Electrical signal attenuation increases with the square of the distance, so you'll lose ~95% of the power to heat loss in the wires if you try to power Seattle from solar in Nevada

What? HVDC lines are usually estimated to have 3.5% power loss per 1000 km. Since power transmission is done using power lines, the inverse square law doesn't really apply here.

> There are a lot of very good reasons why we haven't covered the desert in solar panels.

That does remain true however. Cost concerns, grid access concerns, environmental concerns are all good reasons.

badc0ffee 3 days ago | parent | prev | next [-]

Confidently, impressively wrong. Imagine how the power grid would work if there were 95% losses over 900 km.

3 days ago | parent | prev | next [-]
[deleted]
Rebelgecko 3 days ago | parent | prev | next [-]

Seattle is fine on power, you can pave the parts of the Mojave in California to power California instead (although tbh I think what we need most in CA is storage for when the sun goes down).

I think you can also reduce heat loss by cranking the voltage up, right? I imagine that's how current interstate/cross-country power deals work

downrightmike 3 days ago | parent [-]

Bigger interstate wires hold more power and have a much higher thermal mass, which is fine until someone's tree shorts everything out because lines sag greatly with more heat/power

derefr 3 days ago | parent | prev | next [-]

I'll ignore your other points, because sibling comments are addressing them better. So here's something more unique:

> Also the permitting of stuff across state lines is so time-consuming it's effectively illegal.

This is true in general, but in this specific case, there are a lot of obvious ways to get around the problem, because Nevada is a moth-eaten shirt of federal land reservations — Nevada-the-political-entity only owns/regulates ~15% of the land of Nevada-the-geographic-territory.

With the current state of the US federal government, lobbying to privately use one of those federal reservations would be a walk in the park; and once you're going "California -> federal land" instead of "Calfornia -> Nevada", regulation gets a lot simpler.

Fun fact: there's a National Forest in Nye County (bordering California) that runs right up to the edge of the DoE-reserved area where they did the nuke tests. The feds are fine with running HVDC lines through National Forests (they're not Parks, after all), and "repurposing nuked ground for solar" is actually an easy-to-sell narrative at all levels. You could build solar there and backhaul it to California without ever touching land regulated by Nevada-the-political-entity.

amanaplanacanal 3 days ago | parent | prev [-]

Seattle isn't a good example, as they have been carbon neutral since 2005. They have lots of hydro power in the Pacific Northwest.

dwedge 3 days ago | parent | prev [-]

Paving deserts with black heat absorbers that are only 10-20% efficient in converting that energy to electricity could well end up affecting climate more than burning coal would

glenstein 3 days ago | parent | next [-]

1% from a Dyson Sphere would be a better energy return than 100% efficiency from any conventional energy sorce. Similarly, 20% from solar is competitive with 60% from nuclear, 50% from coal, and is easily better than 100% from my neighbor Dan riding a bicycle powered electricity generator.

You can't cite efficiency percentages in a vacuum to imply they are a better or worse than alternatives, because those aren't percentages of the same kinds of things, and they don't tell you about the economics, production in absolute terms or EROEI.

Ardon 3 days ago | parent [-]

The solar panels would overheat (and lose efficiency), since ~80% of the solar energy hitting it is absorbed as (mostly) heat.

Generating solar energy in deserts is often done with a mirror based heating system for this reason.

glenstein 3 days ago | parent [-]

Something like 98-99% installed solar capacity in the American southwest is traditional PV. Mirrors are there, and they're awesome, but PV dominates.

PV are designed to account for heat and "less efficiency" means they risk performing at 17-18% instead of 20%. And it's actually generating more total energy at 18% because more total sunlight is hitting it, an advantage in desserts.

Ardon 3 days ago | parent [-]

Yeah that's true.

I was thinking more long term though, deserts see much faster yearly degradation than places with more normal temps. (up to 2-3% compared to the standard 0.5-0.8%)

That's just an economic factor rather than a blocker. PVs are cheap as right now, and could be even cheaper if they weren't tariffed. I wouldn't be surprised if PVs in the desert is nonetheless the right approach right now, and not concentrators.

downrightmike 3 days ago | parent | prev | next [-]

They're blue, and nothing about coal would be less impact.

Coal starts with pulling down entire mountains to get to the coal. The whole process starts with environmental destruction and that's how it ends.

The thermal mass of the panels is no where near significant. Especially compared to a run away greenhouse effect we know coal to cause.

dwedge 3 days ago | parent [-]

It's about the localised thermal effect in a desert https://www.westernsydney.edu.au/hie/stories/news_archive/so...

easygenes 3 days ago | parent | prev [-]

Definitely not. At global scale, the offset effects of solar installations outweigh albedo effects on the order of about 30x. [0][1]

  [0] https://www.nature.com/articles/s43247-024-01619-w.pdf
  [1] https://acs.figshare.com/articles/journal_contribution/Net_Radiative_Forcing_from_Widespread_Deployment_of_Photovoltaics/2871685
dwedge 3 days ago | parent [-]

It's about the localised effect of the heat generation https://www.westernsydney.edu.au/hie/stories/news_archive/so...

easygenes 3 days ago | parent [-]

I wouldn't give much credence to that report, as there is no demonstrated understanding of PV site installation management principles (e.g. bright ground treatment). They deliberately highlight a worst case scenario (covering 20%+ of the entire Sahara in unmanaged high density PV) and shove a quick note at the end saying that they modeled 5% and even without other mitigations that was fine. Their model also doesn't include the carbon offsets at all, so it's absolute worst case and entirely unrealistic.

With proper site selection and albedo managed via density and bright ground treatment, you can expect net neutral local heat impact.