Originally published on Solar Love.
A new solar cell efficiency record has been set by China’s Trina Solar Limited, which announced that its new p-type multi-crystalline silicon solar cell has achieved a solar conversion efficiency of 21.25 percent according to the results of third-party testing. Greater efficiency does not necessarily translate into lower costs, but the manufacturing method is based on Trina’s existing technology and the company anticipates that its new solar cell will provide an extra push to the steep downward trend for the cost of solar-sourced electricity.
Somewhat ironically, the news of additional progress in the solar energy field caps off a series of extremely bad news for fossil fuels — particularly petroleum — beginning with the incredible Volkswagen diesel emissions scandal on up to denial of a permit for the Keystone XL tar sands oil pipeline in the US, and the exposure of ExxonMobil’s duplicity on climate change.
Solar Cell Efficiency Records
Where were we? Oh right, the new solar cell efficiency record. For those of you new to the topic, while complex multi-layer solar cells can already achieve solar conversion efficiencies far greater than 21 percent, relatively low cost and simplicity still provides silicon solar cells with an edge in the marketplace.
Trina Solar had its solar cell efficiency rated by the Fraunhofer ISE in Germany, which just a few days ago issued a report on the current state of solar technology and markets. Here’s what Fraunhofer had to say about solar cell efficiency records for technologies on the market today:
The record lab cell efficiency is 25.6 % for mono-crystalline and 20.8 % for multi-crystalline silicon wafer-based technology.
The highest lab efficiency in thin film technology is 21.0 % for CdTe and 20.5 % for CIGS solar cells.
In the last 10 years, the efficiency of average commercial wafer-based silicon modules increased from about 12 % to 16 %. At the same time, CdTe module efficiency increased from 9 % to 13 %.
In the laboratory, best performing modules are based on mono- crystalline silicon with about 23 % efficiency. Record efficiencies demonstrate the potential for further efficiency increases at the production level.
In the laboratory, high concentration multi-junction solar cells achieve an efficiency of up to 46.0 % today. With concentrator technology, module efficiencies of up to 38.9 % have been reached.
Did you catch that first item where it said the record for multi-crystalline solar cells was *only* 21 percent? Fortunately, the researchers who put together the report prefaced the whole thing by noting that in the fast-paced world of solar cell efficiency development, their information would probably be out of date sooner rather than later.
And, they were right.
The Trina Solar Cell Efficiency Record
That mark of 20.8 percent was probably rounded up from Trina’s earlier record-setting entry for solar cell efficiency, which clocked in at 20.76 percent about one year ago.
If you’re thinking that the difference between 20.76 and 21.25 doesn’t sound all that impressive, consider that even just breaking the 20 percent barrier has been a long, hard slog. Solar cell efficiency for multi-crystalline silicon technology was still hovering around the 19.8 percent mark back in 1999. As described in the solar cell efficiency study we came across, the researchers zeroed in on a “honeycomb” surface, echoing Trina’s Honey Plus brand:
The improved multicrystalline cell performance results [partly] from isotropic etching to form a hexagonally-symmetric “honeycomb” surface texture. This texture, largely of inverted hemispheres, reduces reflection loss and improves absorption of infrared light by effectively acting as a randomizer.
In its solar cell efficiency announcement, Trina notes that it purposefully focused on low-cost, scalable processes to manufacture the record breaking solar cell, leading to high-volume commercial production. Here’s the rundown:
The record-breaking p-type multi-crystalline silicon solar cell was fabricated on a high-quality mc-Si substrate with a process that integrates advanced Honey Plus technologies including back surface passivation and local back surface field. The 156×156 mm2 solar cell reached a total-area efficiency of 21.25%.
Solar Cell Efficiency Up, ExxonMobil Down
Getting back to that bad week for petroleum, ExxonMobil is dealing with a barrage of criticism for knowing all about the global risks and impacts of its products, yet choosing to sit on the facts while supporting a mini-industry of lies about climate science. As of this writing the company is also under investigation by New York State Attorney General Eric Schneiderman, so there’s that.
In a 2008 article, New York Times reporter Jad Mouawad provides a fascinating glimpse into the corporate culture behind the global warming denial strategy. Do read the whole thing but here’s a snippet including a remark by ExxonMobil CEO Rex Tillerson:
What might be called the Exxon Way can be summed up in three ideals: discipline, patience and long-term vision. It is a formula the company drills into its managers from the moment they join Exxon, and which it keeps repeating through their careers. It explains the company’s resilience and its view that it has survived, and thrived, through countless commodity cycles.
“We are all homegrown,” Mr. Tillerson says. “That happens through a very deliberate and very closely managed process, and it starts the day the person walks through the door with us. And we are the product of that system…
TAKE a room full of oil managers, and the Exxon people usually stand out, even as they try not to draw much attention to themselves. They typically band together, and often cultivate an aura of secrecy — and sometimes superiority — toward the outside world.
Image (screenshot) via Trina Solar.
Reprinted with permission.
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