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Comment by rozab | Hacker News Reader

Current solar panels are almost 20% efficient. Even in the most outrageous sci-fi scenario, they could only hope to be 5x more efficient than they are currently, and in any case would require significant land use. Compared to nuclear or geothermal, the ceiling is so much lower.

And then we get all the vaporware viral ops like solar freaking roadways and those water bottles that magically refill from the air with a tiny solar panel, ignoring the laws of thermodynamics but making hella kickstarter bux

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Solar takes much space compared to what? Oil wells and refineries? Gas wells and processing and pipelines? Coal mine and power plant?

Solar can be squeezed into lots of unused spaces, e.g. where I live all new Lidl and Aldi have solar on their roofs, an otherwise empty and unused gray space.

The cool thing about solar is you can fix it on top of current infrastructure. Sure the solar roadways are a ridiculous idea, but putting solar panels on roofs actually makes use of space they can't be used otherwise

There are so many public spaces that would benefit from more shade, where the cost of building that shade could be offset significantly by having solar panels on the top. I'm thinking about things like public parks, car parks, open-air malls, etc.

I am increasingly seeing this exact thing put into practice, but it kind of blows my mind that the uptake has been so slow.

And putting solar on roofs tend to reduce cooling costs by a few percent for a building due to the shade.

And if you have good credit the Sun pays for it. You borrow money, put up panels, and then pay the loan with your electricity and gas budget. Still two weeks away from actual final hook up from the power company but friends with similar have that experience.

When you count for buffer land around nuclear (most don't want to live too close) land use becomes comparable to solar

For example, look at Diablo Canyon site acreage vs the acreage of the new large-scale solar project in Pahrump, NV.

That buffer land can be forest and lots of living creatures. Not a solar panel covered wasteland.

We're commenting on an article about solar panels covering a productive farm. Need not be a wasteland.

Solar installations are generally not placed where there'd otherwise be a forest, at least not where I live. I've usually seen them in deserts (where living creatures would appreciate the shade) or the sort of land people would've already considered wasteland.

Animals and plants are perfectly happy living under solar panels.

>would require significant land use

you're commenting on an article about a solution to that.

We have a need for ceilings. When you account for that the amount of space needed provide ceilings, powering our civilization with solar is a negative number rather than a positive number. Negative, because we can more then power our civilization with existing space through dual purpose structures. An example of this is a solar roof. However, even if you ignore that potential, the amount of space needed is only a few square miles. It's not like it would be the size of a country or even the size of a state. The amount of space is small enough to place in some remote desert and for all intents and purposes to then forget about it.

Like most things, the final answer is probably a mix of everything.

Look at this with satellite view enabled. That's 1.5MW installed capacity right there: https://www.google.com/maps/place/Laudeley+Betriebstechnik/@...

That peak capacity seems a bit high, and just isn't very helpful if there's any volume of solar on the grid. Some back of the envelope calculations for mean output:

Total area: ~5000m²

Annual mean insolation: ~100W/m²

Solar panel efficiency: 20%

Annual mean power output = 5000*100*0.2 = 100kW

And on top of that, you still need either energy storage or rapid on-demand generation (e.g. gas fired) to get you through the Dunkelflauten.

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