einmaldrin_alleshin t1_jacq42c wrote

> Plants are more efficient in terms of energy generated per photon absorbed.

That is an incredibly misleading, since chlorophyl does not absorb all photons. It doesn't absorb any infrared, and is mostly transparent between 500 and 600 nm. So by that measurement, you're not counting about half of all sunlight that hits a plant. Silicon based solar may be less efficient per photon, but it absorbs everything from 800nm up to UV.

> but this could be fairly easily addressed when adapting the technology for a PV cell.

You mean DSSC cells? I suppose it's "easy" to demonstrate the effect in a lab under controlled conditions, but in real world applications, where they need to work for decades exposed to the environment, it stops being easy and becomes very, very hard. There's a reason you can't buy them.

They are also not projected to be more efficient than regular solar panels under sunlight, there's just hope that they might become cheaper.


einmaldrin_alleshin t1_jacjjlu wrote

Plants are significantly less efficient than solar panels, particularly because they are limited by the amount of CO2 that they can get. 400 PPM is a lot when it comes to climate change, but when you're trying to synthesize carbohydrates, that's a problem.

On top of that, photosynthesis only works in a narrow temperature range, it requires a lot of water that just gets evaporated, and it requires minerals and nitrogen, which have to be produced expending a lot of energy.


einmaldrin_alleshin t1_j0naiie wrote

Concrete wouldn't be scalable though, because the mass that can be lifted is limited by the weight that the mechanism can move up and down. So you get a few minutes of power at most before all the weight is on the ground.

With pumped hydro, any single pump and turbine can pump water between huge reservoirs. They can potentially provide power through an entire night or more.

So gravity storage with solids is more an alternative to flywheels and batteries, which have a much different role in the grid.


einmaldrin_alleshin t1_iwg9u13 wrote

No. If you're on the outside of the wing, you're sitting at the long end of a lever. The barrel of a conventional airplane meanwhile is the fulcrum. So where you would barely feel the plane going into a bank if you're sitting in the barrel, even slight corrections would noticeably move passengers up and down significantly in a large flying wing.