energy alternatives

Solar power is good enough for the biosphere, so by golly it’s about time it was good enough for human industry! Of course, photosynthesis is only 6% efficient. That number includes the biological losses, the absorption ratio (if I understand the numbers from that link correctly) is 34%. According to various sources the absorption efficiency of solar panels seems to max out around 40%, with power conversion efficiency of 6%, so state of the art is roughly comparable to nature (though of course, manufacturing cost is another matter). However, a new nanomaterial-based coating seems to have been developed that boosts absorption by ~40%:

The new RPI solar cell is a normal cell covered in a special anti-reflective coating which traps sunlight from nearly every angle and part of the spectrum. The new cell is near perfect; it absorbs 96.21 percent of the sunlight shined on it, while a normal cell could only absorb 67.4 percent. That 43 percent efficiency boost, coupled with mass production, if properly implemented could place solar on the verge of competing unsubsidized with coal power, at last.

Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation describes the breakthrough, stating, “To get maximum efficiency when converting solar power into electricity, you want a solar panel that can absorb nearly every single photon of light, regardless of the sun’s position in the sky. Our new antireflective coating makes this possible.”

This is pretty exciting, especially if the mass production can work out. Even if power conversion efficiency stays the same, improving absorption by 40% should boost the total power output by the same amount.

3 thoughts on “energy alternatives”

  1. What I wonder about is, given all the recent advances in solar cells, will it ever become competitive to wrap a flame in solar cells? That way you’re limited only by how bright you can make the flame instead of how much solar radiation you can capture. They’re starting to come up with coatings that they claim can capture most of the photons available in sunlight, so we might be approaching that sort of thing.

    Imagine an internal combustion engine with no moving parts…

  2. Heh. if you scale up your idea, you’re talking about a Dyson Sphere 🙂

    Unfortunately, if you really did try that, you might get good photon absorption, but the inefficiency of converting the fuel for the flame into the fire then gets multiplied against your existing inefficiency factors. It doesnt make a lot of sense for example to burn a pile of wood to capture the photons to get electrical energy; just burn the wood and use the heat to boil water and drive a turbine instead. The efficiency is better that way, especially if you try to go the Carnot Cycle route.

    Ultimately, we already have a great source of photos – the Sun – and theres no matching its output with anything we can devise down here. The trick is harnessing it. I like the idea of the whole solar panels in space, low-power microwaves beaming it down to sea-based stations idea myself, but the big problem there is how do you get the energy to the grid… well, a big problem, if not the big problem.

  3. Yeah, well, I ain’t a physicist, so I tend to get confused on the whole infrared vs heat thing.

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