Gas power stations can be turned on and off quickly. The perfect companion to solar electricity. Because within a couple of decades solar will be so cheap during the day that nothing can compete with it.
-- Dirk http://www.neopax.com/technomage/ - My new book - Magick and Technology
-- http://www.amonix.com/
Careful. Remember the scene in Idiocracy when Not Sure goes to the hospital...
-- Cheers, James Arthur
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aA thesis at a minimum, decreasing the SNR of the literature . If all goes well, even better: grants and 'green' jobs.
-- Cheers, James Arthur
These sorts of development are interesting when real, entertaining when not.
Let's look at some of the math, shall we?
"A six-inch square silicon wafer in traditional photovoltaic (PV) panels produces about 2.5 watts of electricity."
6" sq. =3D 0.023 m^2. Peak insolation is around 1kW/m^2 in the US, so 1kW/m^2 x 0.023 m^2 =3D 23W. 2.5W / 23W ~=3D 11% conversion. So far so good."That same-sized wafer, cut into hundreds of square-centimeter cells in the Amonix 7700, each teamed with a Fresnel lens, produces more than 1,500 watts. It reduces the required area for cells 500 times."
That implies 500 suns' concentration, reduced by the added efficiency factor 31%/11% or about 175 suns.
175 suns on a 1 cm sq. cell is about 18 watts' insolation. Seems workable.
A congressman asked me why, if we can now run a whole LED flashlight on a single alkaline AAA cell, why can't we (Congress) scale that magic battery technology up and run electric cars on it?
He was a decent guy AFAICT, well-intentioned, and prepared (and in a position) to commit several billions to exactly that.
-- Cheers, James Arthur
You obviously missed your big opportunity:-) More seriously, how about a campaign to only elect people who have a scientific or technical background to major political positions?
All of the Chinese leadership are scientists or engineers by training - and it shows.
-- Dirk http://www.neopax.com/technomage/ - My new book - Magick and Technology
Maybe not. That concentration works out to ~17-18W / cm^2. That's not obviously impossible.
Oops-I just posted the same. Should've read the whole thread first.
as.
It would be more believable if they posted an actual price/KWH. Figures I've seen used before, um, lied.
Our Don Lancaster says a PV cell in the US yields roughly 5 hours' peak output equivalent per day. So, that 1MW for 750 houses is about
6.7KWHr / day per house, which isn't unreasonable. Just do all your air conditioning and cooking during the day, when you aren't home.Pumped-water storage is used in California:
You'd think the losses would have to be large though, yes? Turbulent flow, x2, etc. That reduces the effective efficiency compared to conventional methods.
-- Cheers, James Arthur
Fields is fixated with me. Kinda sick and iccky, in my opinion. He goes ballistic when I express opinions, even when I express reasonable opinions.
He told me he loved me once... look it up. That's even more iccky.
John
But it will require active cooling. If we are being generous then at default solar flux the ambient surface temperature is T ~ 300 (a nice round number 330 might be more accurate for sunny deserts and no wind).
Left to its own devices a PV cell receiving 500x more sunlight will end up at T*(500^(1/4)) ~ 5T or 1500K. I grant you it is below the melting point of silicon on my lower estimate but at that flux density you are reliant on the flow of cooling water to keep the thing from cooking!
The Fresnel lenses still have to be the same size though. And I thought that of these technologies the non-focussing flux concentrators were preferred since they also work with diffuse light as well as sunshine. These are spin offs from HEP photon collecting and counting systems.
And the PV converts about 10-20% of that into electricity.
There is another more fundamental point here. The sun is an extended object and round so the matching optics had better be right. A 1cm solar cell to get a 500x increased flux would require a 25cmx25cm fresnel lens in front of it with 1m effective focal length (doable).
My experience of flux concentrators with PV systems has been that they do cook themselves fairly easily for even modest increases in flux density of 3-10x - although it is the plastic parts that fail first (either going opaque, yellow, brittle or combinations of all three).
In its favour if you can keep the system from cooking at these flux densities you only need 1/500 of the amount of exotic semiconductor. Is this thing a real product operating somewhere or a venture capital launch announcement of an investment "opportunity".
Traditional model is that you export it to the grid and it helps cool your workplace or run industry when you don't need it.
Regards, Martin Brown
A pal of mine at IBM Watson (Ted van Kessel) is doing 2500 suns, also with Fresnel lenses and water cooling. The key is the thermal interface material between the silicon and the cold plate--he's using a liquid metal TIM that he invented some years back, and which is used in high-end Apple machines.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 email: hobbs (atsign) electrooptical (period) net http://electrooptical.net
Less than that--you're forgetting the new cells' 3x higher conversion efficiency.
I looked up the efficiency of pumped storage--70-85%. That's pretty decent.
-- Cheers, James Arthur
Yes, but in a manly way - not like you were a sheep or something
-- Dirk http://www.neopax.com/technomage/ - My new book - Magick and Technology
The problem is the size of the lakes required. Pumped storage has to be done on a big enough scale to replace a significant fraction of fossil and nuclear during the night (or during a week of cloudy weather).
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 email: hobbs (atsign) electrooptical (period) net http://electrooptical.net
Jim Thompson wrote in news: snipped-for-privacy@4ax.com:
I wonder how long the acrylic lenses will last in sunlight. and what sort of maintenance they will require,how much scarce water will be needed to keep the lenses clean.
Besides,the solar cells themselves only last 20 years.
-- Jim Yanik jyanik at localnet dot com
Phil Hobbs wrote in news: snipped-for-privacy@electrooptical.net:
of course,there aren't too many lakes in the deserts where the solar plants will be located. then there are the pumping losses,evaporation losses,etc.
-- Jim Yanik jyanik at localnet dot com
What's the mean time between being blown away in thunderstorms?
John
I agree. In fact, my understanding is that aircraft communications often still uses regular old AM specifically because doubling (two simultaneous transmissions) on AM has a far better chance of still being intelligible (you hear both tranismissions) vs. FM (where either both parties end up obliterated or the capture effect just gets you the stronger guy) or digital modulation schemes.
---Joel
Wait, wasn't nuclear supposed to be so cheap that it wouldn't be worth metering it? :-)
Granted.
Though it will depend on how well the exotic semiconductor holds up under the daily thermal stress which is going to be non trivial with agressive cooling on one side and 500x concentrated sunlight on the other. I can see it working in the lab OK for a year or two. But for 25 years under the rigors of real world conditions...
Nuclear goes to cover base load during the night and you use pumped storage to cover short duration fast transients like everyone turning on the kettle at half time in the world cup (World Series final) or whatever. The pumped storage generators can go from a standby tickover to 1MW synchronised output in under 16s which is impressive.
In countries at lower latitudes with significant daytime aircon load the insolation and electricity demand are fairly closely correlated.
Until we have cheap and photostable organic semiconductors that are screen or inkjet printable I think solar PV will always be a novelty that is usable only in the sunniest locations or off grid. Having said that market distortions have made it attractive for higher rate taxpayers to install a PV array if they have the room. Where else can you get a government guaranteed 8% ROI for 25 years today?
Regards, Martin Brown
Don't waste your time Jim, Leftist Pansies have not a clue about doing an ROI calculation.
They also believe that electricity for cars comes from the tooth fairy ;-) ...Jim Thompson
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