Solar Cell Surpasses 40 Percent Efficiency~ (NREL) verified the milestone.

Boeing ^ | Dec. 06, 2006 | Boeing Press Release

[Ernest_at_the_Beach]

ST. LOUIS, Dec. 06, 2006 -- Boeing [NYSE: BA] today announced that Spectrolab, Inc., a wholly-owned subsidiary, has achieved a new world record in terrestrial concentrator solar cell efficiency. Using concentrated sunlight, Spectrolab demonstrated the ability of a photovoltaic cell to convert 40.7 percent of the sun's energy into electricity. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colo., verified the milestone.

"This solar cell performance is the highest efficiency level any photovoltaic device has ever achieved," said Dr. David Lillington, president of Spectrolab. "The terrestrial cell we have developed uses the same technology base as our space-based cells. So, once qualified, they can be manufactured in very high volumes with minimal impact to production flow."

High efficiency multijunction cells have a significant advantage over conventional silicon cells in concentrator systems because fewer solar cells are required to achieve the same power output. This technology will continue to dramatically reduce the cost of generating electricity from solar energy as well as the cost of materials used in high-power space satellites and terrestrial applications.

"These results are particularly encouraging since they were achieved using a new class of metamorphic semiconductor materials, allowing much greater freedom in multijunction cell design for optimal conversion of the solar spectrum," said Dr. Richard R. King, principal investigator of the high efficiency solar cell research and development effort. "The excellent performance of these materials hints at still higher efficiency in future solar cells."

Spectrolab is reducing the cost of solar cell production through research investments and is working with several domestic and international solar concentrator manufacturers on clean, renewable solar energy solutions. Currently, Spectrolab's terrestrial concentrator cells are generating power in a 33-kilowatt full-scale concentrator system in the Australian desert. The company recently signed multi-million dollar contracts for its high efficiency concentrator cells and is anticipating several new contracts in the next few months.

Development of the high-efficiency concentrator cell technology was funded by the NREL's High Performance Photovoltaics program and Spectrolab.

[Moonman62]

You're right. The cells in this article are for special applications.

[hoosierham]

So-called grid intertie systems are way cheaper because of no batteries.
You can also sell or share power but if the grid goes down,your converter shuts off (or at least disconnects from the grid).Big problem if the sun isn't shining on your panels right then!
Grid intertie systems MUST stop sending power to the utility wires in case of any problem lest the line repairman be killied by your power.And it takes less electricity than you might think to kill a person.
I prefer a system with storage or at least alternate generator capabilty.

[Recon Dad]

You are "Mister Wizard". Oh, I might be dumb in math and science, but I do know the P.E. doesn't stand for "Physical Education". Thanks

[hoosierham]

Thanks for putting it better than I did;do you read Homepower,etc?

Anyone interested in this topic should go to Homepower website where you can download a sample issue of the magazine and various topical bulletins. THey have years of experience .WArning to the rigid-minded:the viewpoints tend to be socialist.I don't let that stop me from using the good info .

[Robert A Cook PE]

No big deal.


Solar "constant" is an ideal measure: treat it as if it were the ideal solar power theoretically available at your location at the instant of high noon. (In space, a 1 sq meter solar cell aimed directly at the sun receives 1.0 solar constant of power. Note that I said "receives" the solar constant. It can't turn all of that power into anything useful either!)

So, in our real world of dirty collectors and moving suns and clouds and dust and reflections from the face of the collectors and .....

...

http://www.glumac.com/section.asp?catid=140&subid=152&pageid=533

This article gives some "real world" efficiencies and terms:

The sun produces light at a fairly constant rate. The energy contained within that light is represented as the solar constant. The solar constant is 1353 watts per square meter in space and about 1000 watts per square meter (95 watts per square foot) at sea level at the equator at solar noon.

Photovoltaics (PV) is a solid-state technology that converts solar radiation directly into electrical power, with no moving parts, requiring no fuel, and creating virtually no pollutants over its life cycle. As long as the sun is shining, energy can be developed directly by use of a PV module.

The PV effect is the physical phenomenon of converting light directly into electricity. Edmund Becquerel, a French physicist, first observed this phenomenon in 1839. He discovered that illuminating one of two electrodes in a weak solution produced a voltage. During the 1880s, the first PV cells were made from selenium. These preliminary cells operated with a conversion efficiency of 1-2%.

New photovoltaic technology was developed to power satellites, as part of the space program in the 1960's. In addition, advancement in the transistor industry provided for better materials. PVs and transistors are made from similar materials and many of their working principles are determined by the same physical mechanisms.

Today’s PVs are made from silicon, similar to semiconductors. Through a process called doping, the silicon is separated into two distinct layers, called negative (n-type) and positive (p-type.) The n-type has an excess of electrons, and the p-type has vacancies or missing electrons. The two layers are separated by a n-p junction.

Light passes through the thin n-silicon layer and hits the p-silicon layer. The light is absorbed by the p-silicon layer. The photons in light displace the electrons in the p layer. Some of these displaced electrons have sufficient energy to pass through the n-p junction to the n layer. A potential is developed between the n and p layers. For silicon, this potential is approximately one-half volt. By connecting the n and p layers through wires and a load, current (electrons) can flow from the negative layer back to the positive layer. The electrons which have returned to the positive layer, are once again available for displacement, resulting in a completely renewable resource.

Photovoltaic Cell Crystalline Solar Cell

Single crystal silicon cells have a theoretical efficiency of 29%. The maximum efficiency achieved in a laboratory was approximately 24%. Single crystal silicon cells are not commercially viable to mass produce.

Poly-crystal silicon cells are the most popular of the PV cells on the market today. The cells are widely used in calculators, watches, landscape lighting, etc. The cells are relatively easy and cheap to manufacture with little loss in efficiency over the single crystal cells. Typically, the poly-crystal cells on the market today reach a maximum of 15% efficiency. The general rule of thumb is to figure a net of 10 watts per square foot of solar array surface area.

The major disadvantage of the poly-crystal cells is the wasted materials in the manufacturing process. The poly-crystal silicon is cast and sliced into thin silicon wafers. During the slicing process, almost half of the raw silicon is lost.

Thin-film Cell

In order to lower the manufacturing costs, a thin-film solar cell was developed. The thin-film method uses less material and makes available a more automated manufacturing process. In addition, the thin-film can be incorporated into many building materials and applications.

The big disadvantage to the thin-film cells is their relatively low efficiency. However, as more applications are available, more surface areas are utilized for PV production, offsetting the lowered efficiency. Typically, the efficiency of the thin-film PV cell would be approximately 8% or about seven watts per square foot. The film can be applied to roofing materials, siding, etc. The film can also be applied to skylights and perforated with a laser to achieve the desired light transmission.

The various PV panels would be interconnected through series/parallel connections to develop the desired voltages and currents. No maintenance is required for the PV panels. Having been designed for the rigorous demands in space, PV modules can withstand high temperatures, and direct impact from rocks or other projectiles.

[thinkthenpost]

100 milliamps IRC, a number easy to reach.

[dhuffman@awod.com]

I prefer Messrs. Heckler and Koch's compact Universal Selfloading Pistol in .40

But the epigraph refers to the supposed differences between various citizens, like legislators, cops and felons.

Either we are equal or we are not. Good people ought to be armed where they will, with wits and guns. NRA KMA Merry Christmas

[SauronOfMordor]

40% is very high

Once you have achieved 40%, the game then becomes how cheaply can you make them and still maintain the efficiency.

The Total Cost of Ownership for solar power has as main components

1. Capital cost of the solar cells
2. Cost of the real estate they occupy
3. Depreciation (how long do they last before they need to be replaced)
4. Operation (Washing the dirt and bird droppings off them so the sunlight can get thru)

[dr_who_2]

The fine print from spectrolab's web site:

How does a concentrator system lower the cost of solar energy: Under 500-sun concentration, for example, one square centimeter of solar cell area produces the same electricity as 500 cm2 would without concentration. The use of concentration, therefore, enables the replacement of the more expensive semiconductor area with cheaper materials (e.g., lenses or mirrors). The use of concentration, however, requires that the module use a dual-axis tracking system, in addition to providing an efficient heat removal mechanism. Still, the savings in the semiconductor area and the higher output due to the use of the higher cell efficiency make the use of HCPV modules with MJ cells more economical.

[UB355]

http://www.homepower.org

Look through this publication for a lot of information

[Tolerance Sucks Rocks]

Sounds good to me!

[Recon Dad]

I've got a "little" HK Mark 23 if we're talking H&K's, actually I gave it to my son.

[Ernest_at_the_Beach]

I need to find a picture of that appartus the DOE had set up outside of Barstow...

[Ernest_at_the_Beach]

Concentrating Solar Power

This is about the Large setup at Kramer's Junction,....west of Barstow.

[mountn man]

H&K USP Tactical in .45

[Covenantor]

ummmm ....you forgot the real biggie. Energy storage, that means batteries. And that to the real estate as well as control circuitry. Last time I looked that doubled the installation cost. Imagine the user disposal fees(taxes) that will be imposed once the storage batteries come to the end of ttheir life span

[plymaniac]

Homepower Magazine has good reference information in their archives. I used part of it to design, buy and install my off-grid PV system. But their editorial policy is as left wing as a $3 bill.

[G-Man 1]

Bet they would work good on the moon and mars.

[TKDietz]

The price per watt is still probably high, but this is a huge improvement. The average solar cells people have on their roofs now are only about ten to fifteen percent efficient if they've purchased them in recent years, worse if older. Cells with efficiency of 10% will produce about a hundred watts of power per square meter during peak sunlight hours. Sunlight at ground level is supposedly the equivalent of one kilowatt of electricity per square meter. Panels that are 100% efficient would generate one kilowatt per square meter during peak sun hours, or something like five or six kilowatt hours per day depending on how much sun they get in the area where the panels are set up. Cells that are 40% efficient would then put out around 400 watts per square meter during peak sun hours. That means with 40% efficient panels we can produce four times as much power per square meter of panels than we would get with standard 10% efficient panels still common today. It probably also means a reduction in price, since less materials will be necessary to set up the two or three or more kilowatts worth of solar panels people like to set up for home power. Costs for solar panels and other equipment you need to set up a solar power system for your home have slowly but surely been going down, and efficiency of the panels is going up. Big strides in efficiency like this hasten the day when solar power systems will be providing a big part of the electricity homes and businesses need. It will be a while before that happens but in the mean time you're going to see more and more solar power being utilized for small gadgets, remote equipment that needs power, maybe cheap solar panels for your work truck to keep your power tools charged, and so on. I remember being amazed by solar powered calculators, and things like the solar powered school zone signs with the flashing lights, and seeing solar panels at gas wells. As efficiency improves and price goes down we'll see a lot more innovative uses for solar power in addition to seeing more solar panels on homes and businesses for supplementing power from the grid.

[NicknamedBob]

"Bet they would work good on the moon and mars."

The problem on the Moon is the long period of darkness. That's why NASA is now talking about landing at the Lunar poles. The Moon has a flatter orbit than Earth's, and a simple tower will elevate your solar collector into the sunshine -- 24 hour sunshine.

On Mars, one again has an approximately twenty-four hour day, generally clearer atmosphere, but weaker sunlight. The mirrors would have to be larger, in order to concentrate more.