40% efficient solar arrays and Elon Musk batteries

LOL!

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I have often thought, why not build a home with a solar panel roof. No roof boards, no shingles, just solar panels. It would dramatically offset the building costs.

Then put a small windmill on every house. Even if it's only 5', it will generate something. And the cost would not be that much if there were millions made every year.

The extra electricity generated by the small power generators, combined with LED bulbs, would be a huge savings of oil/coal. And make us less dependent on foreign energy sources.
 
Of course no mention of what it costs to get to 40%. I don't expect it will be cheap - the theoretical limit on solar cell efficiency is ~ 33%, you need multiple cells stacked to capture different wavelengths to exceed that limit (alluded to in that article with their 'optical bandpass filter'). Further, they mention 'concentrated sunlight', so now we are adding lenses and/or reflectors - more expense, and possible tracking mechanisms.

Batteries are expensive storage, and will need to be replaced in 10 years or so. That 'free electricity' is going to pricey, I fear.

https://en.wikipedia.org/wiki/Shockley–Queisser_limit (emphasis mine)

The limit places maximum solar conversion efficiency around 33.7% assuming a single p-n junction ... The most popular solar cell material, silicon, has a less favourable band gap of 1.1 eV, resulting in a maximum efficiency of 29%.

The Shockley–Queisser limit only applies to cells with a single p-n junction; cells with multiple layers can outperform this limit. In the extreme, with an infinite number of layers, the corresponding limit is 86% using concentrated sunlight.[3]

edit/add: small windmills. We've discussed this before. Small windmill output is so tiny in comparison to large ones (factoring in amount of materials), that it really is a waste of resources. They just don't scale down very well. You need to be up high to catch steady winds. The power generation falls very, very rapidly (cube factor, IIRC) as wind speed drops. Far, far better to put up one large one than one hundred ones that are 1/100th the size.

I agree with you on conservation, but I'm not sure lighting is the 'red X'.

-ERD50
 
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40% solar panels are incredibly expensive.
They are not used in residential, nor commercial applications.
They basically are only used in space.

Batteries, on the other hand hold more potential. There are a few options for residential solar backup and we are starting to figure out grid level storage (besides the standard hydro pumping which works well as long as you have a dam nearby).
 
Another interesting thing is the work on super capacitors. They may become an alternative to batteries in electric cars. They would recharge much quicker.
 
Another interesting thing is the work on super capacitors. They may become an alternative to batteries in electric cars. They would recharge much quicker.

Interesting yes, but they have been 'the next big thing' for a few decades, with no real indication of bringing them to market. EEstore was supposed to be the furthest along, but many questions still exist.

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

Fast recharging requires a huge power source. If you want to charge 100x faster, you will need 100x the amps and cables and conductors 100x larger (in cross sectional area). That might not fit in a car.

That still leaves you with all the problems of EVs, cost, the pollution from generating the electricity, and range.

-ERD50
 
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