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A long awaited solar power milestone for unconcentrated silicon PV cells has been reached, thanks to steady improvement and research

While many traditional fossil fuel technologies show slow growth in efficiency and design, solar power has instead yielded steady and rapid advances.  While many question why a "killer app" solar product has not yet reached the market after years of hype, it is hard to deny the fact that solar costs both subsidized and unsubsidized have been dropping dramatically, being halved every 10 years. 

With current costs ranging from 15 to 20 cents per kWh, and wholesale coal power costs between 1.5 and 2.5 cents per kWh (and nuclear in a similar range -- 1.7 cents per kWh by estimates from the Nuclear Energy Institute), solar still has a ways to go and likely a few decades before being ready for full deployment.  Still, few technologies show the rapid growth in efficiency solar has and few utilize such a common resource as silicon, so the value of ongoing solar research is apparent.

UNSW's ARC Photovoltaic Centre of Excellence reported a significant milestone this week, with the announcement of the world's first 25 percent efficient unconcentrated solar silicon cells.  They had previously held the 24.7 percent efficient silicon cell record, but were denied the 25 percent milestone due to gaps in the understanding of sunlight and its effect on silicon.

New research has led to revisions in how incident light efficiency is calculated.  As a result, their record-holding design has reached the 25 percent mark, a "magic" number according to many industry experts.  The cell, designed by Professors Martin Green and Stuart Wenham has a wide lead over competitive offerings, according to the Centre.  UNSW holds six solar world records now.

Centre Executive Research Director, Scientia Professor Martin Green described how the new research improved the understanding of the efficiency.  He states, "Since the weights of the colours in sunlight change during the day, solar cells are measured under a standard colour spectrum defined under typical operational meteorological conditions.  Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green."

While suggesting less green of anything may seem like heresy in the alternative energy industry, it’s good news for the Centre as it means their cells are operating more efficiently than expected.  The Centre's cell posted larger gains than its competitors following the revision.  It is now 6 percent more efficient than the next most efficient competitor, according to Professor Green.

The Centre's cell is approaching the important 29 percent efficiency threshold -- the maximum theoretical efficiency for a first generation silicon photovoltaic solar cell.  Dr Anita Ho-Baillie, who heads the Centre's high efficiency cell research effort, says the new research is a big boost "because our cells push the boundaries of response into the extremities of the spectrum."

She states, "Blue light is absorbed strongly, very close to the cell surface where we go to great pains to make sure it is not wasted. Just the opposite, the red light is only weakly absorbed and we have to use special design features to trap it into the cell."

Professor Green states, "These light-trapping features make our cells act as if they were much thicker than they are. This already has had an important spin-off in allowing us to work with CSG Solar to develop commercial 'thin-film' silicon-on-glass solar cells that are over 100 times thinner than conventional silicon cells."

The biggest goal of UNSW is now to adapt the ultra-high efficiency cells for mass production which should lead to more cost reductions.  ARC Centre Director, Professor Stuart Wenham, adds,"Our main efforts now are focused on getting these efficiency improvements into commercial production.  Production compatible versions of our high efficiency technology are being introduced into production as we speak."

The center has a close relationship with the world's biggest solar manufacturers, thanks in part to Dr Jianhua Zhao and Dr Aihua Wang, who fabricated the record-setting cell and have since left the Centre to establish China Sunergy, one of the world's largest photovoltaic manufacturers.  Professor Green describes, "China was the largest manufacturer of solar cells internationally in 2007 with 70 per cent of the output from companies with our former UNSW students either Chief Executive Officers or Chief Technical Officers."

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RE: 25% = 24.7%
By theapparition on 10/24/2008 8:57:37 AM , Rating: 4
I don't think even the most die-hard nuclear proponents are against research into any alternitive green energy. Right now, none of those has proven to be as reliable and cheap as nuclear energy.

I'll be the first one to cover my house with solar panels if it every makes practical sense. Until that time, why wait around, invest in proven technologies. If we would have done that with building refineries and leasing ANWR (a completely desolate frozen marshland), we would never have been in this mess to begin with. The worst thing we can do is wait.

RE: 25% = 24.7%
By The0ne on 10/24/2008 9:49:33 AM , Rating: 1
Solar power does make practical sense. I know of a few people here that had their home covered with panels. It supplies enough for everything except when they have the AC running. In fact, it supplies more than enough you get credit for some of the unused energies. So instead of the meter moving clockwise, it's moving counter-wise...go figure. So what's your definition of practical that's not making you go solar now?

So even though the investment might be a bit high, the returns are there after a few years. Having said this the download to what I've seen at their homes is the lack of a storage device for the energy.

RE: 25% = 24.7%
By Schrag4 on 10/24/2008 10:52:53 AM , Rating: 3
You must live in a place where the sun shines. A lot. There was an article a while back on this site that had a link to some company that sells solar cells intended for home use, and according to their estimates (I followed the link, filled out the form), it would have taken me over 20 years for the system to pay itself off.

I agree, solar is practical for some, but not for all.

RE: 25% = 24.7%
By The0ne on 10/24/2008 1:15:13 PM , Rating: 2
Definitely not for all. And yes we do get a lot of sunshine here in San Diego :) When I asked my friends they said it would take them around 8-12 years for the return, depending on the usage of course. The best example I have to give would be a single guy and his dog in a big house and he's only paying taxes on electricity which is a few dollars.

So while it will take years to get your return back if you think short term you're not paying the few hundred dollars per month that you normally would. You could also look at it like saving some money here and investing it or putting into a interest accruing account and it'll lessen the number of years you have to wait :) But then I wouldn't be investing too much of it right now :D

RE: 25% = 24.7%
By ebakke on 10/24/2008 1:56:25 PM , Rating: 2
And, in CA you also get a pretty hefty government subsidy to help out with solar panel purchases.

RE: 25% = 24.7%
By Keeir on 10/24/2008 3:25:33 PM , Rating: 2
A few notes:

#1. Large subsidies for Solar Panels in San Diego
#2. One of the highest Solar Irradiance places in US
#3. No Time Value of Money, Maintaince Costs, etc
#4. Artifically High Electricity costs due to legalization that prevents Coal, Nuclear, etc power plants (Supply and Demand) + Taxes etc on Power

As Jason notes in this article, Electricity produced from Coal and Nuclear is very very cheap in comparison to Solar Rates as well as typically charged rates for delievered power.

Personally, I think Solar will not have "arrived" till it is profitable when sold wholesale

Right now thats around 44.0 dollars per MWh or 4.4 cents per kWh. A cost that is 1/5 the best case senario for Solar.

RE: 25% = 24.7%
By JediJeb on 10/24/2008 11:04:01 AM , Rating: 2
For me practical would mean it cost less than having the electricity coming in from the meter, that includes the cost of purchase and installation. If you have the extra money lying around to purchase these then maybe it makes sense, but for those who really have no extra money on hand it doesn't at this time. It's like deciding to buy a $15 shirt or a $75 shirt, one covers you up, the other covers you up and leaves you $60 to buy food and gas.

RE: 25% = 24.7%
By MozeeToby on 10/27/2008 12:17:00 PM , Rating: 2
A better way to look at it would be, does the system save me more money if, instead of buying solar panels, I had put that money into a CD or Money Market account (especially now as Money Market's are insured).

So, it isn't enough to say that your $10,000 solar setup saves you $1000 a year and you will break even in 10 years. If you had put that money into a no risk CD (say 3% these days) you would have had $13,500 after 10 years so you are still behind. For the sake of argument, lets assume that upkeep and loss of efficiency are about equal to increasing electricity costs. In all actuality, you wouldn't break even until 18 years into your investment.

Of course, there are other benifits of installing solar that have nothing to do with money. With a good setup, you can power essential appliances in your home during a blackout. You have a certain amount of independence, increasing electricity costs won't effect you as much. And, if you're into that kind of thing, you can get nice warm fuzzies from the idea that you're helping the environment.

RE: 25% = 24.7%
By croc on 10/24/2008 8:54:14 PM , Rating: 2
Playing devil's advocate, if enough houses had extensive solar arrays, the net benefit to the electrical grid might be negative relative to their output. Say 1000 houses in a given area produced a total of 10000 KW, the supplying substation might not be able to handle the extra load without upgrading a few xformers or dumping the excess. I don't see a private company spending the shareholders' money 'uselessly', do you?

So much of the US electrical grid runs so close to the edge of safe operating limits now, upsetting the balance either has 0% or a negative effect.

RE: 25% = 24.7%
By Shining Arcanine on 10/28/2008 11:32:17 AM , Rating: 2
I would prefer a Mr. Fusion Home Energy Reactor over solar panels any day of the week.

All of this research into "alternative energy" is a huge waste of money, particularly because even if all of these technologies operated at their theoretical limits, they would never be a proper alternative to nuclear power. The atom's internal energy is far greater than anything you can get outside of it, even if you can only get a fraction of it.

This research is hindering research into Mr. Fusion Home Energy Reactors and I don't believe our tax dollars should fund it.

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