Why 13-year-old's solar power 'breakthrough' won't work

Aidan Dwyer's tree-inspired array for solar panels had the web buzzing, but not everyone believes it's more efficient.
Written by Tuan Nguyen, Contributor

Ahhh the internet. One minute you're the latest media sensation with a groundbreaking idea. The next minute you're the latest over-hyped media sensation with the not-so-groundbreaking idea. This is the circumstance that Aidan Dwyer, a 13-year-old boy, may have unwillingly found himself in.

Last week, the web was abuzz with news that the 7th grader from New York had developed a new design layout for solar cells. After completing an experiment, he concluded that his oak tree-inspired model may improve efficiency by an unheard of 50 percent over conventional arrays. He came up with the idea during a winter hiking trip in the Catskill Mountains, where he noticed that the tree branches grew in a spiral pattern resembling the Fibonacci numbers, a mathematical sequence often found in the structure of plants.

It was the kind of story that fans of science can't help but be enthralled with. A precocious youngster has a nature-inspired "eureka!" moment, which may lead to a breakthrough that turns an entire multi-billion dollar industry on its head. If not quite made-for-Hollywood, it's definitely feel-good enough to garner him a Young Naturalist Award from the Museum of Natural History and for front page play on several popular news sites and blogs that obviously didn't hesitate to jump all over it.

But no sooner as word spread did a natural peer-review process started to kick in as some readers started poking holes in Dwyer's research. One blogger, however, took the scrutiny one step further, posting an entire explanation complete with rigorous scientific data and charts debunking his findings.

Writing on the capacity factor, an energy blog, the person wrote:

This is, I'm sad to say, clear nonsense. I'll take this in two parts: one, why his experiment is, unfortunately, completely broken (sorry again). Two, why the imagined result is impossible nonsense.

Broken experiment

Most importantly, by mistake he did not measure power outputs from the solar cells. Instead he measured voltage, without a load attached ("open circuit"). They are barely related -- in solar cells, voltage is actually almost a constant, independent of power.

The actual power delivered by a solar cell is not linearly related to the open-circuit voltage; actually, as a semiconductor, it has a horribly nonlinear relationship.

Now I'm not a solar energy expert myself, but I found the writer's assessment of the theory to be quite convincing. So to get to the bottom of this brewing controversy, I got a hold of someone who has made it his life's work to make solar arrays more efficient and cost effective.

I spoke to Jan Kleissl, professor of environmental engineering at the University of California in San Diego, who, first and foremost, praised the youngster for doing a "amazing job" carrying out the experiment. Kleissl did, however, agree that the flaws pointed out by the blogger were on point because a measurement of the actual current would have shown it to be much lower.

"Using just the voltage to say a panel is more efficient at producing energy is similar to saying I have a fast car because I can drive from San Diego to Seattle," Kleissl said in a phone interview. "They can't be correlated like that."

While he conceded that Dwyer's arrangement offers a slight advantage over standard panel arrangements in the morning hours -- when a few of the panels would be in position to catch more sunlight -- he was quick to point out that a standard solar array would produce a lot more energy around noon and overall because the panels will be facing the sun more directly.

"People have this tendency to believe that nature is head of us and that if we replicate it, all of our problems will be solved," he says. "But we are really way ahead of nature."

To drive that point home, he says, for instance, that plants are only one percent efficient at converting sunlight into usable energy (sugar), while solar panel designs are now 20 percent efficient. He also added that since determining the best panel arrangement can be done simply by running various designs through a simulation, a much bigger help to the industry would be to fix other non-technical issues like simplifying the permitting process.

And in case you're wondering what the most optimal way to position solar panels, his answer is "it depends."

For instance, placing them at a 180 degree angle works well in most parts of the world, but in regions like California the best angle is 10 degrees west of south due to the fact that morning clouds block much of sunshine until the afternoon hours. To help California residents predict how much solar energy can be generated from their own systems, Kleissl's research team has created a free solar density map that can be downloaded at http://solar.ucsd.edu/.

Rajiv Varma of Western Ontario University, who develops experimental solar power systems seconds Kleissl's assessment that Dwyer's solar array project won't improve the energy output of solar cells, though he sees a lot of promise in the young student's work.

"What I would really like is that this young man should not be discouraged by telling him that what he has proposed is wrong," Varma wrote in an email. "But instead help him getting in touch with researchers or academicians working in this area so that a bright mind is nurtured in this area."

(via The Capacity Factor, The Atlantic)

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