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MIT Solar Towers Beat Solar Panels By Up To 20x
An anonymous reader writes "A team of MIT researchers has come up with a very different approach to solar collectors: building cubes and towers that extend solar cells upward in three-dimensional configurations. The results from the structures they've tested show power output ranging from double to more than 20 times that of fixed flat panels with the same base area (abstract, full pre-print). The biggest boosts in power were seen in the situations where improvements are most needed: in locations far from the equator, in winter months and on cloudier days."
Use 50 times as many solar cells, and OF COURSE you'll get more power out.
The cost/watt is higher, this is DOA I dare say.
They're simultaneously saying that it's most beneficial for northern/southern areas where daylight is diminished and that it's a more compact arrangement of cells.
Those two don't go together well... Most northern and southern areas have very large open areas due to having low overall population density.
Cost/Watt is all that matters in most areas for solar panels, Watt/weight in the rest. I can't see this being of use except in powering small devices
20x output (compared to a flat panel with the same footprint).
Not really news. This is like excitedly proclaiming that a 20 story building has nearly 20 times the floorspace of a single story building with the same footprint. Uh, no shit? (Or that a 20 story building receives more insolation than a 1-story building; hmm, you think maybe it has a lot more surface area?) I also like that they hand-wave away the fact that it costs significantly more per unit output by saying that cells are getting cheaper. Great.
Not that there aren't uses - it absolutely makes sense to go this route where you have limited footprint space - but it just doesn't seem at all revolutionary. I guess if you tack the letters M-I-T onto a press release it instantly becomes newsworthy.
Quick, someone alert all of the major energy companies so they can buy up the patents and sit on them for eternity!
Well, no. The 7th grader built a single physical model and made rough measurements of it's performance at a single location across a limited span of time. The MIT team built a computer model that can analyze any given configuration and simulate it's output across a wide variety of locations and wide span of time - including variations in seasonal weather patterns.
I'm not saying that what the 7th grader did wasn't cool - but he's built a pinebox derby car, while MIT has built a fully solar powered 55mph family sedan. Apples-to-oranges doesn't even *begin* to describe the differences, not only of degree but of kind, between the projects.
Under conditions where you can see the sun - that's true. But the point of TFA is that these 3D structures are more efficient *in situations where sun trackers aren't more efficient*.
Conditions exactly like those currently outside my window - where the sky is nearly uniformly bright but you cannot see the sun at all due to the clouds. Conditions that are fairly common here in the Pacific Northwest.
It's a stupid concept. If I had been asked to review their paper I would have recommended not publishing it. Here's a link to their abstract:
http://pubs.rsc.org/en/content/articlelanding/2012/ee/c2ee21170j
"We demonstrate that absorbers and reflectors can be combined in the absence of sun tracking to build three-dimensional photovoltaic (3DPV) structures that can generate measured energy densities (energy per base area, kWh/m2) higher by a factor of 2–20 than stationary flat PV panels for the structures considered here, compared to an increase by a factor of 1.3–1.8 for a flat panel with dual-axis sun tracking."
Yet they admit the following: "The increased energy density is countered by a larger solar cell area per generated energy for 3DPV compared to flat panels (by a factor of 1.5–4 in our conditions)...." IOW, they need a larger cell area by a factor of 1.5 to 4 to generate a given amount of energy than would be needed by a flat panel! So they admit their concept is a factor of 1.5 to 4 less efficient than a flat panel. But how can that be true, if their design generates significantly higher energy densities?! Probably they're merely generating higher peak energy densities at certain times and in certain localized regions of their solar panels, while their average energy density (averaged over their entire solar-panel area and over the entire operation time) is lower by a factor of 1.5 to 4.
All they're really claiming is that they can reduce the variability of the power generated by stationary solar PV panels:
"3DPV structures can mitigate some of the variability inherent to solar PV as they provide a more even source of solar energy generation at all latitudes: they can double the number of peak power generation hours and dramatically reduce the seasonal, latitude and weather variations of solar energy generation compared to a flat panel design."
But is a reduction of variability worth sacrificing total energy production by a factor of 1.5 to 4? Not likely.