Viewing a single comment thread. View all comments

seidler2547 t1_ixz4yde wrote

Reply to comment by Gibbons74 in News Release: NREL Creates Highest Efficiency 1-Sun Solar Cell - 39.5% efficiency by TimeSpentWasting

Fact about solar cells you should know:

> The maximum theoretical efficiency calculated is 86.8% for a stack of an infinite number of cells, using the incoming concentrated sunlight radiation. When the incoming radiation comes only from an area of the sky the size of the sun, the efficiency limit drops to 68.7%.

178

TimeSpentWasting OP t1_ixzcmaf wrote

Never knew why, now I have the answer without googling. I'm lazy, so thank you

I have high hopes that humanity will reach that maximum value as tech gets smaller. I wonder how much efficiency is reduced under heavy cloud cover?

28

skittlesmcgee33 t1_ixzuftk wrote

That maximum is functionally impossible. Functional limit is in the 40-49% range so we’re already most of the way there.

52

PM_Your_Wololo t1_iy0pk6k wrote

Can you ELI5 why the difference is so large?

4

ThatOtherGuy_CA t1_iy0ubqo wrote

Material costs, eventually the amount of materials you need to add per extra % is more than just building a second panel at the same efficiency. So around 50% in order to get an extra 1% in efficiency, you need a panel with double the cells. So you might as well just build 2 50% efficiency panels rather than 1 51% one.

That’s basically why most panels are stuck around 23% right now, it’s more cost effective to just build 2 panels than to build a panel 1% more efficient.

Basically as technology advances it gets easier to improve the efficiency with less waste, but around 50% is when you can’t really make anything smaller to get those efficiency gains in a similar sized panel.

30

LouSanous t1_iy4302w wrote

>So you might as well just build 2 50% efficiency panels rather than 1 51% one

The most recent info I was able to find shows it to be like 300:1. Standard utility scale solar panels in the 20% efficiency range are 1/300 the cost of triple junction GaAs.

1

ThatOtherGuy_CA t1_iy47zui wrote

Yup, which is why you pretty much only see them in space applications. Because the weight saved can save enough fuel costs to offset the insane price increases.

1

LouSanous t1_iy4fmek wrote

I'm not sure how much it costs spaceX with their reusable rockets (and given that Musk is in charge, I would bet that he never did achieve the multiple orders of magnitude cheaper costs he promised), but prior to the space shuttle cost per kg into space was $18,500. After the space shuttle, $54,500/kg.

1

zeuszoso t1_iy10kez wrote

The practical limit given by Shockley and Quiesser for a single-junction solar cell under 1 sun illumination is 33% power conversion efficiency.

20

Valmond t1_iy10l2x wrote

So when we close in on the theoretical max, should prices drop more?

1

anglesideside1 t1_iy36zrs wrote

Efficiency gains are great, but the bigger gains are to be had in manufacturing, installation, and overhead costs. If we’re just talking residential, companies spend a couple thousand in customer acquisition costs per installation. The utility scale stuff is MUCH cheaper per kW, but can still wring out some more savings in siting, permitting, interconnection, and overheads. Panel efficiency gains tend to help more when space is more of a concern. If you can spread out, then much cheaper, less efficient panels are often the better choice.

2

zeed88 t1_iy35ssy wrote

How about using thermoelectric coupler underneath it to absorb the heat and turn it to energy, will that increase the percentage?

1