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Comment by topher515 | Hacker News Reader

This article made me think of the endless "solar farms" scene from Blade Runner 2049[1]

That scene is quite plausible! People have calculated that we could supply all of Earth's (present) energy needs by covering just 1.2% of the Sahara desert in solar panels [1], and there would be positive side effects on the local climate to boot. Of course, we would never actually get all our energy in one spot, since there are questions of transmission, redundancy, political instability, etc. But it does point toward a future where lots of otherwise-useless desert land (like in SoCal, where the Blade Runner movies take place) is converted into solar farms.

[1]: https://science.sciencemag.org/content/361/6406/1019

I'm going to bet power consumption is like hard drive space, the more you have the more you use.

There is of course some thermodynamic limit to the amount of power we can use before over heating

The trend towards better energy efficiency has all but stalled increasing energy use per capita in developed nations. And effective efforts at water conservation show that it is possible to pull back consumption in some cases, even if the natural trend is increased consumption.

That’s because incentives shifted toward decreasing peak demand.

Not at all! For the last few decades, reductions due to efficiency gains has far outpaced increased demand. For example, we nowadays build much more well-isolated homes which reduces the need for electrical heating in colder climates, and air conditioning in hotter ones. I don't think there is any Western country in which the per capita consumption of electricity has grown significantly over the last 20 years.

Consumer electricity is expensive. In some ways it's good because it drives the economics behind efficiency, but in other ways, it's unfortunate that energy is such a large part of the average American's monthly budget (electricity, oil, natural gas, and gasoline).

Cheap energy is an extraordinary economic driver. Cheap green energy is a double win.

Surely electricity prices have something to do with that, I hope in future energy becomes abundant enough that we can waste it without costing a fortune or destroying the environment. I want my toilet seat warmers and aircon, I want my PC to be as fast as possible and not throttled, I don't want to feel guilty about using a clothes dryer. On the bigger scale imagine what we could do with cheap water desalination and removing dams.

The environment is being destroyed right here and right now. Are you willing to risk it being destroyed more because you want toilet seat warmers and a clothes dryer?

Sorry if this makes you feel more guilty.

Do you have a source that controls for real electricity prices? Coal prices for example have risen faster than inflation over the last few decades (coal ~$30->$88 [0] vs inflation expectation $30->$42 by the US BLS calculator 2003-2019) and the renewables that have been bought online weren't exactly cheap.

There is always going to be a sink for more power, because all else failing electricity can produce more aluminium products, and aluminium is one of those wonder materials that there will always be uses for. We know that energy efficiency can just as easily cause consumption to rise as to fall [1].

[0] https://www.statista.com/statistics/214236/thermal-coal-pric... [1] https://en.wikipedia.org/wiki/Jevons_paradox

Still, you can always only go so far with efficiency gains - they are important, but should not be depended on instead of looking for new cheap & clean energy sources.

And there are also some technologies, that while very energy hungry, can help fix many of the pressing world problems (large scale desalination, plasma waste processing, large scale CO2 capture, various benefiting megaprojects, etc.).

> There is of course some thermodynamic limit to the amount of power we can use before over heating

The benefit of solar is that no new energy is produced this way. You consume what hits the Earth anyway.

Things might change if and when we cover so much ground with panels, we change the global albedo significantly. But we're a long ways off from that.

Somewhat surprisingly, this doesn't seem to be the case. Your average middle-class person in the west probably uses less today than 30 years ago; all major appliances (particularly lighting and heating) are more efficient, TVs are much more efficient, cars are much more efficient.

World power consumption is going up largely due to a rapidly growing middle class, but within that class, not so much.

However, if we're going carbon-neutral people driving gas cars and using gas to heat their homes may well end up needing electricity for those as well.

So we might expect an increase in per-capita demand for electricity, if not for total power.

It doesn't seem optimal to put them in a circular formation like that, though. From wherever the sun hits, some panels will be hit from the side and the light will miss the panel completely. It looks cool, but it doesn't seem realistic.

Those are concentration mirror, they reflect light onto the spire in the middle which had a receiving element at the top. Conventially they're used for thermal application where you use the sun to generate steam at the top of the tower, although there has been research into beam down variants where the light is reflected down to a very high efficiency PV cell.

Elaborating slightly, this works because some types of solar panels can be overloaded by several orders of magnitude so long as the panel temperature is kept low enough.

I believe those are mirrors, not solar panels. They're reflecting the light onto a solar power tower:

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

Here's a real one:

https://ths.rwth-aachen.de/wp-content/uploads/sites/4/gemaso...

Strange that they put mirrors on maybe 1/6 of the land. I'm sure they have a reason, but I wonder what it is?

To prevent mirrors shading each other. If you look at the upper part of the photo, it's almost a uniform mirror from this point of view. But if you look at the bottom, there's lots of spaces. The overlap/spacing is likely optional for reaching the tower.

otherwise-useless desert land

This is a phrase you should remove from your vocabulary. Just because the desert hasn't been paved over doesn't make it useless.

Source: Lived in the desert.

There is a wide variety of deserts. Some of them have rich, interesting, valuable ecosystems, possibly including the one(s) you lived in. And some of them are most certainly useless.

This is like describing the aroma of a gardenia or the sound of your child singing to herself as she plays as “almost certainly useless”.

But still, if we are going to have solar panels somewhere, I'd rather have them in a desert where there is not as much wildlife to disrupt as in, say, a forest or grassland biome. It's not like we're at risk of running out of deserts, either.

(1) Generally this is not good ecological thinking. Disrupting a robust biome like grassland or rainforest is much more difficult than disrupting a fragile one like desert or tundra, and robust biomes recover much faster if you do manage to disrupt them. I think it happens to be correct in this case because the panels will tend to strengthen the biome by providing shade rather than disrupt it.

If you go around disrupting desert biomes on a large scale, you cause desertification, converting the adjacent savanna and forest biomes into semi-arid desert. So even if you don't value desert for itself, that is foolish planning, unless your aim is to harm wildlife and the humans alike.

(2) We aren't at risk of running out of children, either, but that doesn't excuse neglecting or sacrificing them.

Hardly, the amount of extreme desert vs the amount of people that want to visit is an extreme over supply. On the other hand people actually spend effort growing flowers.

PS: Joy is a recognized form of economic benifit.

Next step: the Dyson sphere

https://earthsky.org/space/what-is-a-dyson-sphere

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

I think a dyson sphere would be great more for helping us prevent global warming than generating cost efficient electricity. Opening and closing the dyson sphere to control radiation flux would be a cool thing. We'd have planetary AC

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