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Comment by s1artibartfast | Hacker News Reader

It all comes down to the economic tradeoffs. Panels are cheap and everything else is expensive.

If you can get 75% efficiency for half the cost, your return on investment is 50% higher

What you lose with Erthos' approach is any possibility of using bifacial panels.

In regions that get snow, bifacial panels (that use light reflected onto the back of the panels as well as light from the front) get a lot better output in the winter, increasing the annual capacity factor and therefor return on investment. (Winter electricity can be more valuable too, in those regions.)

Horses for courses.

you can have a back mirror on this, they probably do

Solar in Texas seems like an obvious win in just about any configuration. But I wonder how this would work at higher northern latitudes in the winter. I suspect efficiency would be pretty bad with a 20 degree incidence.

Doesn't have to be effective everywhere for it to be useful.

the unintuitive part is that land is even cheaper than panels, so you'd think that spending more panels to use less land would be a losing proposition

the interesting question is whether the costs of racking, grading, cleaning, repairing, etc., go up or down, and if they go down, whether it's enough of a reduction to make up for the larger amount of solar panels per average watt, as they say it will be

Based on my calculations, at my latitude (40 degrees North), you would need about 16% more panels to generate an equivalent amount of energy per year. This isn't taking into account potential issues with snow buildup (which theoretically would be worse with flat panels) or the effects of cooling (which theoretically could be better due to contact with a thermal sink, the ground), but it's probably pretty close. Even if 20% more panels are required, that means capital costs are superior as long as panel costs are less than 5x racking material and labor costs. Currently panel costs are more like 3x racking costs and will probably continue to decline. Racking costs will probably not go down unless steel prices go down pretty significantly. The only thing that surprises me is that there are not more companies doing this. Perhaps there are factors that neither Erthos nor I am properly considering, but I think this is how most utility solar projects will be done in 5-10 years.

We put in 40 KW and in the racking was a nightmare. The government required soil analysis, reinforced racks, and cement pilings 4 ft deep. Probably could have put in double the panels if we didn't have to deal with the f*** racks

I think this approach has interesting applications for small-scale solar in rural environments if the permitting can be streamlined

I mean with erosion, flooding, and the like, I'm not sure this sort of mounting on the ground would be any less of a hassle...

Most of those things seem nonissues in desert climates with flat Terrain.

steel prices are probably not a significant component of racking prices; scrap steel costs 50¢ a kg

the numbers they gave make the pv module prices seem slightly higher than the cited racking prices (15¢ per watt) but it's a little hard to be sure because of the numerous kinds of watts involved

Panels may be cheap, maintenance / replacement is less so, because humans at work.

They use a robot for regular cleaning; looks like the design will make that cheaper too as it's basically a fancy Roomba.

Replacing might be cheaper as well without any mounting racks or tracks.

Everyone is talking about maintenance ITT. Is it that big of a concern? My parents have had solar on their roof for almost 10 years now with zero issues. I imagine newer panels last longer.

So what's the actual maintenance cost? I could imagine it's going to be cheaper to just install new panels every few decades than constantly maintaining the installation to be 100% capacity.

For a grid scale installation, let’s say 5% of panels are dead due to whatever failure. I am not sure the rational response would be to do any maintenance vs installing more capacity. Twenty years later rip out all of the old panels, replace with new. Repeat forever.

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