Published on December 29th, 2009 | by Susan Kraemer3
Prism Makes $1 a Watt Unique Solar Hybrid of Holographic Thin-film Strips AND PV
Here is an innovation borne of the need to make solar modules that are more able to capture more sunlight in regions like New York (or Germany) that have relatively low level insolation. Normally that means that it takes more panels to make the same power, which means it simply costs more to make the same electricity in upstate New York than in the Southern California desert.
Prism Solar Technologies in Highland, NY has innovated a breakthrough holographic thin-film (Holographic Planar Concentrator™) that makes possible a very parsimonious use of crystalline PV cells to counteract that problem for Northern regions.
This brings the cost down to $1 a watt.
Each of their solar modules is actually made up of both crystalline PV and their unique holographic thin-film. The thin-film strips diffract both direct and reflected energy to the PV cell strips integrated between strips of thin-film. Solar modules made in this way are cheaper because they use 50-72% less silicon to make the same energy. This PDF is very informative.
The modules use light from any direction, even from the back.
When mounted on a white roof, the bi-facial modules can generate as much as 30% more energy, because the thin-film picks up from the back surface as well. It can receive light both directions. With the thin-film bouncing irradiance back, the PV is getting two and a half to three and a half times more light, even when the sun is at low angles.
Here are the advantages of Holographic Planar Concentrator™ (HPC) technology:
- Less silicon reduces cost per watt
- Passive tracking from holographic effect produces more energy from diffuse and reflected light.
- Cooler operation than conventional PV module, most unusable light passes through module without being turned into heat.
- Bifacial PV cells can increase module performance when mounted over a reflective surface.
- Lower embodied energy, the energy required to manufacture the HPC film is much less than that required to mine and process silicon.
This video explains how the PRISM holographic solar increases the efficiency by capturing even low angle light . In HPC modules the PV cells are diced into narrow strings to be placed between rows of HPC film. Dicing and finishing the strings improves electrical flow, adding another 3/4% efficiency over full-size cells.
An array of these modules can be mounted in any direction – even North.
Its passive tracking can work in any orientation. This means roofs that are slanted in the wrong direction for solar, such as north-sloping roofs, could also now be used to make energy. Arrays mounted on the wrong angle will be up to 30% more inefficient, depending on how steep the angle is, and how much it faces true North.
Normally, an incorrect roof orientation makes solar on the wrong roof prohibitively costly, as it takes more panels to do the same work. Prism’s approach solves that problem, as it levels the playing field for those whose roofs are not perfect.
Even vertical walls can be used.
Windows could be comprised of these holographic modules. This could be integrated into buildings designed from the start to generate electricity. Buildings create 35% of our greenhouse gases by requiring fossil-fueled electricity.
Buildings designed with this technology from the start can be Net-Zero – buildings that need no fossil energy and generate no greenhouse gases, even if you don’t live in the desert. And if you do, solar just got a lot cheaper, for you too.
Image: Prism Solar Technology
Source: Sun Volt