Could be another pie in the sky idea, but one could always hope. – Anthony
A new catalyst could help speed development of inexpensive home-brewed solar energy systems for powering homes and plug-in cars during the day (left) and for producing electricity from a fuel cell at night (right). Credit: Patrick Gillooly/MIT
BOSTON — The era of personalized energy systems — in which individual homes and small businesses produce their own energy for heating, cooling and powering cars — took another step toward reality today as scientists reported discovery of a powerful new catalyst that is a key element in such a system. They described the advance, which could help free homes and businesses from dependence on the electric company and the corner gasoline station, at the 240th National Meeting of the American Chemical Society, being held here this week.
“Our goal is to make each home its own power station,” said study leader Daniel Nocera, Ph.D. “We’re working toward development of ‘personalized’ energy units that can be manufactured, distributed and installed inexpensively. There certainly are major obstacles to be overcome — existing fuel cells and solar cells must be improved, for instance. Nevertheless, one can envision villages in India and Africa not long from now purchasing an affordable basic system.”
Such a system would consist of rooftop solar energy panels to produce electricity for heating, cooking, lighting, and to charge the batteries on the homeowners’ electric cars. Surplus electricity would go to an “electrolyzer,” a device that breaks down ordinary water into its two components, hydrogen and oxygen. Both would be stored in tanks. In the dark of night, when the solar panels cease production, the system would shift gears, feeding the stored hydrogen and oxygen into a fuel cell that produces electricity (and clean drinking water as a byproduct). Such a system would produce clean electricity 24 hours a day, seven days a week — even when the sun isn’t shining.
Nocera’s report focused on the electrolyzer, which needs catalysts — materials that jumpstart chemical reactions like the ones that break water up into hydrogen and oxygen. He is with the Massachusetts Institute of Technology in Cambridge, Mass. Good catalysts already are available for the part of the electrolyzer that produces hydrogen. Lacking, however, have been inexpensive, long-lasting catalysts for the production of oxygen. The new catalyst fills that gap and boosts oxygen production by 200-fold. It eliminates the need for expensive platinum catalysts and potentially toxic chemicals used in making them.
The new catalyst has been licensed to Sun Catalytix, which envisions developing safe, super-efficient versions of the electrolyzer, suitable for homes and small businesses, within two years.
The National Science Foundation and the Chesonis Family Foundation provided funding for this study. Nocera did the research with post-doctoral researcher Mircea Dinca and doctoral candidate Yogesh Surendranath. The U.S. Department of Energy’s Advanced Research Projects Agency has recently awarded the team with a grant, which it plans to use to search for related compounds that can further increase the efficiency of its electrolyzer technology. The team hopes that nickel-borate belongs to a family of compounds that can be optimized for super-efficient, long-term energy storage technologies.
The American Chemical Society is a non-profit organization chartered by the U.S. Congress. With more than 161,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
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hotrod ( Larry L ) said on September 2, 2010 at 10:59 pm:
That’s why you get the flexible thin-film PV laminates that come in a roll, they don’t shatter. They’re durable, made to be unrolled over tin roofs and flat roofs. There’s a “limited power output warranty” good for still getting 80% after 25 years (click on item numbers for the pdf’s). They use triple junction technology, and yield more energy than crystalline PV cells. They also work at lower levels of light, and don’t have to be directly aimed at the sun. Just unroll (adhesive backing), wire up (quick connect), and don’t worry about them.
If I was going to try solar, this is what I would buy.
kadaka (KD Knoebel) : thin film solar.
Sort of. If you go through the numbers, they run about half the efficiency of the expensive crystalline cells. The Uni-Solar panel is rated at 144 watts, for a 2 sq. m. panel. A good silicon panel might produce 400 watts in that size. Thin film is cheaper, for sure, but not more efficient. And you still need batteries. That’s the real gotcha. A fuel cell is nothing more than a battery with separate storage for the elements involved. Low voltage, so you need a bunch in series. You can run a survival cabin on 12 or 24 volts, but real world, you need 120 or 240 vac. That means an inverter and some serious voltage driving it. So lots of cells, which need careful circuits to prevent a single cell crash. The Tesla Roadster has over 6800 “C” cells in it’s battery pack, in series/parallel configuration. An engineering marvel, but not cheap.
That’s why I favor thermal. A single storage “cell”. Heat is about the lowest form of energy, but it does follow the KISS concept. Wonderful and complex doesn’t do much good if it breaks.
RE: kadaka (KD Knoebel): (September 2, 2010 at 11:41 pm)
“… How does that match up to your dream?”
It has occurred to me that something like this might be *theoretically* possible. I vaguely recall that I may have heard or seen a news item about radioactive deposits somewhere at sometime creating a possible ‘natural reactor’ a day or so before my dream. I believe this was over ten years ago.
“”” kadaka (KD Knoebel) says:
September 3, 2010 at 1:09 am
hotrod ( Larry L ) said on September 2, 2010 at 10:59 pm:
Retired Engineer says:
September 2, 2010 at 5:54 pm
PV’s aren’t there yet. 20% efficiency or less, and only if pointed directly at the sun. If your roof is not at the right angle, you have to tilt the panels. Which works at noon, less well before and after. Plus little things like hail, dust, blowing sand and the like. I’ve seen several solar panels in Colorado smashed to bits by our ‘interesting’ weather.
That is what stopped my off grid experiment, my solar panel array got turned into a lot of little solar panels when a thunderstorm developed when I was not home.
Larry
That’s why you get the flexible thin-film PV laminates that come in a roll, they don’t shatter. They’re durable, made to be unrolled over tin roofs and flat roofs. There’s a “limited power output warranty” good for still getting 80% after 25 years (click on item numbers for the pdf’s). They use triple junction technology, and yield more energy than crystalline PV cells. They also work at lower levels of light, and don’t have to be directly aimed at the sun. Just unroll (adhesive backing), wire up (quick connect), and don’t worry about them.
If I was going to try solar, this is what I would buy. “””””
Well I can’t decipher who said what; but perhaps any one of you can tell us what is the conversion efficiency of these “cells”, that is electric power out divided by total ground level solar power in such as Watts per Watt.
If you look at their “superior to any other” chart; you find it is a graph of actual power output versus rated power output. It doesn’t say they produce more power than the competition for the same solar poer input.
Nevertheless, I am intrigued; even impressed by their silicon triple junction technology; BUT !! What are they really doing ?
Their “blue junction for example is simply a very thin junction silicon diode that can absorb blue photons in a thin junction. The longer wavelength photons pass right on through the thin diode on top, and then next one is a bit thicker and absorbs some longer wavelengths. Thge longest wavelengths go through to the bottom thickest Junction.
BUT here is the kicker. The blue cell is absorbing solar photons that may be in the 2.5 to 3.0 electron Volt energy range; but being a silicon junction it will only generate at best about 0.5 Volts DC at optimum lad conditions. So something over 85-90% of the photon energy that is absorbed by the diode, is simply wasted as heat. Lkewise the green junction only produces about 0.5 Volts from say a 2.5 eV photon so it loses 80% as heat.
“Real ” triple junction solar cells would use a wide bandgap material such as Gallium Nitrode, or Gallium Indium Nitride to convert those higher energy Photons into a much larger terminal Voltage than silicon can.
So nowhere in their literature do they quote an actual real sun conversion efficiency; and I’ll bet, that whatever piece of paper they have that written down on is locked in a vault under armed guard somewhere.
So you talk to their jobbers who will sell you a system; and they won’t tell you the number; I doubt that they even know the number. All they want to know is how big an installation do you want to buy and how are you going to finance it.
When these solar companies come out up front and announce on a spec sheet what their conversion efficiency is under what irradiance conditions; I wouldn’t buy a used paper napkin from any of them.
Despite that I do think this Uni-Solar TJ cell is quite an accomplishment. But quit playing stupid games with us; tell us what the true solar conversion efficiency is for production panels.
Here is another concept that caught my eye. They’ve gone commercial. Not sure yet if it’s just a gimmick, or if it actually has merit:
http://www.npowerpeg.com/personalenergy
They have a concept they’re to trial for harvesting wave energy.
From: George E. Smith on September 3, 2010 at 11:33 am
Mine was the un-indented (un-blockquoted) part after “Larry.”
Let’s see… I had downloaded previously the pdf of the 68W strip, just a one-sheet handout page. Check on the back…
They have, of course, the “ideal” Standard Test Conditions (STC) numbers [1000 W/m^2, Air Mass (AM) 1.5, 25°C], but they also have more real-world Nominal Operating Cell Temperature (NOCT) numbers like you’ll find on a rooftop (800 W/m^2, AM 1.5, 1 m/s wind, 46°C) so we’ll use them. Maximum power 53W, total size of strip is 2.849m by 0.394m (112.1″ x 15.5″, fits between the standing seams of a tin roof). Yields 47.2 W/m^2, about 6% efficiency.
Note the chart showing amperage produced for irradiance amount, at STC you should expect 1.0A per 200W/m^2.
The too-simple one on this page? Nah, looks like a marketing department graph. Being triple-junction they do garner somewhat more power than old-fashioned basic crystalline silicon cells. The major thing to notice on that graph is around sunrise and sunset. These particular flexible ones operate at dimmer light than traditional cells. I’ve read elsewhere they work with diffuse light, doesn’t have to be strong and likely direct sunshine, thus they can generate on (lightly?) cloudy days and practically sunrise to sunset.
This leads to the graphs on pg. 3 & 4 of the Energy Production Brochure (link to pdf found here). The “superior to any other” charts show real-world examples involving about 2 to 4 years of comparison testing (and I agree such third-party results need better citing of their source). Although their amorphous silicon technology is technically less efficient than crystalline silicon, their design yields more kilowatt hours per kilowatt installed than other technologies.
The first pg. 4 graph is interesting. Standard panel mounting is at a fixed tilt, no rotation for sun tracking, just bolt down and ignore. At a 30° tilt the flexible ones easily beat the crystalline panels. But with crystalline at 30° and the flexible at a mere 3°, the flexible technically edges out a win. Now, if you have a commercial building with a flat roof, sloped slightly for rain runoff and preferably southward (Northern Hemisphere), here is a product you can lay right down. It won’t be sticking up like a traditional panel, where it’ll stick out as too noticeable and also be vulnerable to wind. You won’t have the shading issues that’ll plague tilted traditional panels, you can cover practically the entire roof with these strips. So which looks better to you?
The caveat, of course, involves area, they occupy more per watt. But with flat roofs and flat installation you can fit in more units than tilted conventional panels. Around the equator traditional panels may look better, moving poleward things will quickly even out, then flat-mounted flexible is superior.
That might have been the ones used for the Mars rovers, only cost a few million dollars.
As you can see on the lower diagram, the blue, green, and red layers are identified as “cells.” Thus these seem to be actually triple layer. Going by transistor-type notation, I wouldn’t call them “triple junction.”
BTW, interesting note: that entire 68W strip has only 11 cells. With NOTC conditions it generates 15.4V at maximum power, thus with all 11 series-connected that’d be 1.4V per cell. By the voltages you gave and adding in the red layer, if all three layers were series-connected within each cell then the 1.4V figure makes sense.
Yet in this case a simple back-of-the-envelope calculation from company-provided specs teased out that precious figure.
One of the major reasons I like these is it wouldn’t be someone else installing them, it’d be me, paying for everything up front. They install easy, no bracketing and the like, and no screw or nail holes through the roof. Some numbers I’ve seen put them at a higher cost per watt than traditional panels, mainly the cheaper panels, but that neglects installation costs including those brackets and things. The company is forthright on expected degradation over time, see their limited power output warranty. Maintenance is minimal, there’s hardly anything that could go bad.
Currently by Google: Shopping (Product Search) the 68W laminate strip can be had for $250 or less with shipping, around $215 without. The current second-cheapest wants $209.95. Looking at their prices, you can get a 40W panel for $189.95 or a 85W for $299.00. Those three are considered 12V. The 136W strip, considered 24V, is $389.00. For less than $7 more you can get a 80W 12V panel, made by Sharp no less.
If only the stupid inverters didn’t cost so much. You can spend $1500 and up just to have a single grid-tied panel. Yuck.
Now to see what a real rip-off looks like, for $699 you get:
Jeff says:
September 1, 2010 at 6:01 pm
What utter nonsense … when you split water to make the Hydrogen you get the oxygen … can’t make “more” oxygen than is in the water … snake oil …
Jeff: the article says production is boosted, not yield. Processes are never 100% efficient.