CoolEarth Raises $21 Million for Solar Balloons
by Michael Graham Richard, Ottawa, Canada 
on 02.20.08
CoolEarth, a company we've briefly covered before, has created an innovative way to harness the sun's energy. Instead of large expensive solar panels or costly concentrating mirrors, the company is using balloons made of metalized plastic films. Half of the balloon is transparent, letting the light in to be concentrated into a small high-efficiency solar panel by the concave interior. Each is 2 meters across and, depending on the source, estimates vary from 500 watt to 1 kilowatt. They are supported by cables, leaving the ground below clear and limiting environmental impact.
The company has just raised $21 million, and it says that "this is just the initial closing of the round, [it could be extended] over the next 60 days." The company closed a $1 million round of angel investing last June. Read on for more photos and details.
CoolEarth concentrators are suspended in series on support and control cables stretched between poles.
Here we can see how little support material it takes to keep the balloons in place.
“Our goal from the very start was to find a clean energy generation solution that could address the global scale of the carbon problem. We discarded everything that couldn’t scale, relied on rare components, or had some other critical bottleneck. Ultimately, we developed a novel technology which radically reduces the amount of material in our system and balances labor and capital costs,” said Dr. Eric Cummings, founder of Cool Earth Solar.
It is reported that CoolEarth is planning to build a solar farm in the 10 megawatt range in the next few years. It would use about 10,000 balloons over 80 acres.
Above we can better see what the insides of the solar balloon look like. Quite simple and elegant.
::CoolEarth Press Release, via ::Cool Earth Gets $21M for Inflatable Solar
For something a bit similar, see the Technion Institute's solar balloons.
See also: ::Hairy Solar Panels Could Result From Nanowire Breakthrough, ::New Compact Concentrating Solar Panels: Heliotubes, ::Solar Hyper-Concentrators: Reducing The Cost of Solar Power, ::42.8% Efficiency: A New Record for Solar Cells, ::New Solar Panels Produced at Less Than $1 Per Watt
Update: If you are interested in solar power, also check out 15 Photovoltaics Solar Power Innovations You Must See.
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That video says you can fix them with duct tape. How awesome is that?
Using less structure is great, but how much wind can they handle? I'm predicting many new UFO reports if that sun farm gets built. : )
I don't understand why a burger shape is better than a disc. What does the plastic dome facilitate? The shape of the mirror? If so, the shape is not ideal, which is what makes collection mirrors "costly" so just use a cheap, imperfect mirror. Seems like if you are going to capture heat, you ought to use it also.
"Using less structure is great, but how much wind can they handle? I'm predicting many new UFO reports if that sun farm gets built. : )"
The company says it can handle 100 mph wind.
Anonymous: The plastic dome portion allows them to pressurize the interior, allowing them to forgo supports that would otherwise be required to keep the correct shape. This would be a cost saving measure, not to mention the air used to do the support is probably much lighter than any other solution.
How does this solar balloon track the sun? What is the expected price per watt? What is the life expectancy?
How does this solar balloon track the sun? What is the expected price per watt? What is the life expectancy?
What I want to know is the price per watt generated.
This tells us if the balloon be idea is going to be cost effective and competitive with other systems.
The problem with all reflection type solar collectors is that they need to follow the sun and this requires tracking. This idea is no different than other reflectors except for it's light construction. One problem may be lifespan, balloons don't last long.
These negative comments are interesting. Is it easier to knock something down than come up with something yourself? Yes. It takes hard work to develop things that solve multiple design issues simultaneously. Cost, structural integrity, ease of replacement, potential for commoditization, efficiency, green factor, ease of production, connectivity. Just try it sometime, just for a while, before you sit back and criticize someone else's work. Or how about, you propose your much better idea here? Yes, I'm sure everyone would be interested to take a look at your designs.
How they track can be seen from the images. The fourth image somewhat shows the balloon's internal concentrator PV structure . The PV head is supported by a tripod with a fat arm and two thin arms mounted at the balloon's two pivot points. The external upward pointing arms at the pivot points allow all the balloons to be gang tracked by a pair of guide wires running between the towers.
I imagine water cooling is provided by the PV tripod's fat arm and 2 of the arms can be servo adjusted along with air pressure to fine position & auto focus the PV head. The smarts would be in a very small module
and would allow for a small puncture to still operate and could signal for a technician to patch or replace.
I think this could be very scalable indeed and vastly cheaper than
How they track can be seen from the images. The fourth image somewhat shows the balloon's internal concentrator PV structure . The PV head is supported by a tripod with a fat arm and two thin arms mounted at the balloon's two pivot points. The external upward pointing arms at the pivot points allow all the balloons to be gang tracked by a pair of guide wires running between the towers.
I imagine PV water cooling is provided by the PV tripod's fat arm and perhaps 2 of the arms can be servo adjusted along with air pressure to fine position & auto focus the PV head. The smarts would probably be at the fat arms pivot mount and could compensate for a small puncture, signal for a technician to patch or replace and log performance..
These balloons would have very few components to look at which means they could be easily recycled many times with new balloons.
This could be very scalable indeed and looks far simpler than solar thermal generators used in the south west. I'd hope to see these deployed in less sunny regions.