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New World Record in Solar Cell Technology

A concentrator solar cell produced by Boeing-Spectrolab has recently achieved a world-record conversion efficiency of 40.7%, establishing a new milestone in sunlight-to-electricity performance. The US Department of Energy’s National Renewable Energy Laboratory (NREL) verified the milestone.

This breakthrough may lead to systems with an installation cost of only $3 per watt, producing electricity at a cost of 8-10 cents per kilowatt/hour, making solar electricity a more cost-competitive and integral part of the US energy mix.

Attaining a 40% efficient concentrating solar cell means having another technology pathway for producing cost-effective solar electricity. Almost all of today’s solar cell modules do not concentrate sunlight but use only what the sun produces naturally, what researchers call “one sun insolation,” which achieves an efficiency of 12 to 18%. However, by using an optical concentrator, sunlight intensity can be increased, squeezing more electricity out of a single solar cell.

The 40.7% cell was developed using a multi-junction solar cell. This type of cell achieves a higher efficiency by capturing more of the solar spectrum. In a multi-junction cell, individual cells are made of layers, where each layer captures part of the sunlight passing through the cell. This allows the cell to get more energy from the sun’s light.

For the past two decades researchers have tried to break the “40-percent efficient” barrier on solar cell devices. In the early 1980s, DOE began researching multi-junction gallium arsenide-based solar cell devices, multi-layered solar cells which converted about 16% of the sun’s available energy into electricity. In 1994, DOE’s National Renewable Energy laboratory broke the 30% barrier, which attracted interest from the space industry. Most satellites today use these multi-junction cells.

Earlier in November, RoseStreet Labs, LLC and Sumitomo Chemical Co., Ltd. (Sumitomo) formed a joint venture, RSL Energy, Inc., for the development and manufacturing of full-spectrum solar cells. The joint venture will be headquartered in Phoenix, Arizona.

RSL Energy will commercialize next-generation technology utilizing full-spectrum solutions that targets practical efficiencies above 48% in both single junction and multi-junction devices. (Earlier post.)

(A hat-tip to Marty!)




These guys have done some good work. You need to convert more than a narrow band of energy to gain efficiency and multijunction does that. Not cheap, but cost effective.


Concentrators (parabolic mirrors/mirror arrays) just plain make sense to me. I'd like to see a company specialize in concentrators and come up with low cost standardized designs that are easily deployable.

Someone just might be able to make a dime doing that....


Saw this on ScienceDaily and SciAm's web site not too long ago. They're saying that this tech can go into production next year. However, bottlenecks in PV-grade silicon supplies are a major problem. And they're going to be as long as the PV industry is growing 25-35% per year.


Multi-junction PV are made up of more material than semiconductor grade Si. Gallium, Arsenic, Indium, and Selenium, are just a few.


A real-life 8-10 cents per kWh is an economic winner. If you build these scalable (and I can't imagine why not), I could imagine shopping centers, apartment complexes and maybe even private homes installing these things for some real distributed generation. While most customers would almost certainly remain plugged into the grid, cutting consumption of grid electricity would save real money.

Roger Pham

Just think of all the mercury and CO2 NOT released into the air from coal-generating power plant being displaced by this super concentrated PV solution!


Do these concentrator systems have to be kept facing the sun ?
What tolerances do they have ( +- how many degrees )
If so the costs including the heliostat would be much higher than the cells alone.

Also is the 40% just for the cell and if so what degree of light concentration do they get and how big is the cell and concentrator ?

- JM


This is all good and well, but what the heck does it have to do with Transportation? I read this same release last week on Renewable Energy Access.

Yes, I know you can charge your EV or Plug in Hybrid, but the other 99.9999% of the driving world still uses fossil fuels.

Almost all concentrating solar modules require tracking, which increases costs and adds additional failure points for the system.

Thomas Pedersen


Yes, they need to track the sun within a narrow margin, I don't know how narrow. But this also results in higher solar influx per area. I also means that production rises very steeply in the morning, because the only difference between sunrise/sunset and mid day is the absorption through the atmosphere, which is not much.

Most concentrating PVs do not use heliostats, but rather optical or fresnel lenses, thus making a much more compact unit. Concentration can be as much as a factor of 50-100!

Green & Gold Energy have pretty good explanations of both factors



High concentration ratio concentrators (c=100-300) that use these 40% efficient solar cells always have to track the sun (it simply can not be done with fixed system). Cells are not big (a few cm2) but you can connect it in series to get more "surface" which is usually needed for big parabolic dishes.

Tracking accuracy for these big parabolic dishes has to be within +/- 0,1 degree or better - that is hard to achieve, but this year the world has gotten the first commercial ultra high accuracy sensory solar tracker controller - essential device for providing high tracking accuracy.

Please visit to find more.


Solar PV panels are available for less than $5 a watt now with computed lifestime kwhr cost over 27 cents for a large scale commercial application without battery backup. There is more to a PV system than the cells/panels, even not considering battery costs. So, I would like to see an analysis that shows how they arrive at an 8-10 cents per kwhr cost. Perhaps they are assuming a breakthrough in all the other components.

Rafael Seidl

Ian -

a) any oil-derived fossil fuel not burnt for space heating, industrial processes and electricity generation is available for transportation. Plus, net CO2 is net CO2, regardless of source. GHG mitigation is easier to achieve in other sectors of the economy than in transportation, so it makes sense to pay attention to advances in stationary applications as well.

b) if and when PHEVs and BEVs actually materialize, they will be able to recharge off renewable power. Given that the number of people in the "developed" world is due to grow from ~1 billion to today to 2..3 billion by 2050, strategies for reducing and eventually eliminating fossil fuel use in transportation are desirable. It's still early days yet for the new battery chemistries, though, at the scale required for competitive automotive applications.

c) solar and wind electricity can be load-leveled in conjunction with existing, already amortized hydro dams. Another possible but sadly very expensive option is to produce hydrogen and use that to power highly efficient but fuel cells (which still cost the other arm and leg).



I'm not sure if they meant by "may lead to systems with an installation cost of only $3 per watt" but if they mean $3/installed watt then that's considerable cheaper than current systems. The price that you mentioned is just for the cost per watt (peak) capacity but doesn't include installation or component costs (inverters and mounting hardware).

Bill L

I question the price of these cells. I'm sure I read somewhere that one or several of the materials (Indium, Selenium, etc) are very rare. If so, and these cell become popular, these material will be more expensive than gold.


This is a great advancement and may eventually trickle down, but it doesn't seem to have much of an impact on distributing the supply.

Relatively large initial capital, moving parts, precision instrumentation, and lenses/mirrors. This isn't going to end up on a shopping mall roof anytime soon. It could, however, end up in (relatively) large arrays cranking out MWs of power, distributed in the same sense that fossil fuel power plants are distributed.

And hey -- thats OK by me. Sure, the idea of 1,000,000 solar roofs is a cool one, but if there's only 1,000 solar areas-the-size-of-a-Wal*Mart-parking-lot, that's OK too. The point is that you're getting power with a smaller environmental impact and you're getting it positively correlated with demand which reduces the need for inefficient peaking plants.

Paul Dietz

I question the price of these cells.

High concentration cells have much less area per unit of power output, so they are much less sensitive to the cost of raw materials for the cells. They can also afford more sophisticated and expensive designs, for the same reason.


Many factors are helping solar now. And some are pretty mundane technology.

The tracking/focusing mechanisms are growing more reilable, more accurate, and cheaper to build just as are all durable goods such as refrigerators and automobiles and homes.

The efficiency and cost of the cells is falling. Not as much as we would like but..falling. The inverters and controllers needed to get the direct current into the alternating current grid are much cheaper and more reliable than it was five years ago.

Storing the power for use when the sun is down remains the least effective part of the equation. Batteries aren't all we can wish. But even battery costs are falling.

Perhaps best of all. Nations won't quarrel over solar supply. Or run out. No fertile soil or rain is needed.

The costs that seem too high are bargains compared to what widespread solar would have cost a decade ago.


These cells are 1 cm squared and can take 1000 suns. They work optimally around 300 suns, but can take more. They are a good use of indium, considering the efficiency.

P Schager

> what the heck does it have to do with Transportation?

For one thing it proves that 40% solar cells are possible, and reinforces other science that has been telling us that in a few years you won't need exotic materials/construction either, so cells practical for one-sun use will be up there in efficiency too. So this is news that reinforces the case for solar-roof cars, like these.

Also, the PV-EV scenario is the strongest of the cases for why we our oil sycophancy is deluded. Solar panels on your home/building roof to get power for your car already can be cheaper than gasoline, and this points toward improving economics. Electric companies may fight off your ability to get full value ("retail") for daytime solar generation, so you may be better off pumping the power into your car batteries to displace gasoline than letting the electric company borrow it for the day.

Also, with feedback control I don't see why solar tracking should remain particularly more expensive than, say, power windows (similar gear). If the stiffness of the structure isn't enough to keep wind gusts from wiggling up your alignment, just use a second servo to quickly move the small cells themselves a bit to compensate (like astronomers do with adaptive optics).


Solar can have a lot to do with Evs. You could produce enough solar power to go 200 miles a day if you wanted.

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