Move over, solar panels. There are some recent innovations in renewable energy, and they're changing the way we get energy from the sun. Ever since the invention of solar panels in the 1950s, researchers have been working on making them less expensive and more efficient. New methods and materials have brought us closer than ever to a cheap, efficient solar panel that's less wasteful to produce.
Here are some of the most promising recent developments in the solar industry:
One of the arguments against solar panels is that their manufacturing process is wasteful and unsustainable. Organic photovoltaics seeks to change this by exploring abundant alternative materials for manufacturing photovoltaic cells. They could also be used to make transparent cells, suitable for use in building-integrated solar systems.
These cells rely on an absorber made of polymers. This results in a localize exciton (a n electrically neutral particle formed when a material absorbs a photon of higher energy than its energy gap). An electron acceptor, like a fullerene, facilitates electron transfer. What happens is that, when a photon is absorbed by the absorber, it produces an exciton. This moves to an interface between the polymeric absorber and the electron acceptor. The mismatch in energy here splits the exciton, resulting in free charge carriers.
This research is still in its relative infancy. While the technology behind it is extremely promising, it's not yet very efficient. Changes in materials have improved its efficiency somewhat, but there's still quite a long way to go. Once organic photovoltaics can achieve an efficiency closer to standard cells, they'll be a way to create flexible photovoltaic cells from abundant materials, at a low cost.
A flat panel isn't really the most efficient way to use sunlight for energy. This is because it can only really collect photons from one angle. Some panels are able to rotate and track the sun as it changes position throughout the day, but these are more expensive than standard models.
Researchers at Stanford have developed a pyramid-shaped lens device that serves as an optical concentrator. These lenses are able to gather light from multiple angles and concentrate them into a single point. These lens devices—called AGILE for Axially Graded Index Lens—are totally passive, since there's no need for them to rotate or track the sun. They're also tileable, which means that future solar panels could be made up of multiple AGILEs, and custom arrays could even be made to fit a variety of odd-shaped surfaces.
“Perovskite” is a term for any material with a specific crystal structure, ABX3, where A and B are positive ions and X is a negative ion. Perovskite solar cells are photovoltaic cells that rely on compounds with this particular structure. These compounds are typically halides, which are binary chemical compounds made up of a halogen atom and an atom that is less electronegative than the halogen. These compounds are inexpensive and simple to produce, which makes them an attractive alternative to conventional photovoltaic materials.
These solar cells are surprisingly efficient and have made some pretty big increases in efficiency from their inception. That said, there are still some challenges ahead for this new tech. For example, the materials used tend to decompose with exposure to humidity, oxygen, heat, or light. Early perovskite solar cells lasts minutes to hours, while further experimentation has yielded solar cells capable of lasting for months. If researchers are able to further increase the durability and efficiency of these cells, they may eventually replace conventional photovoltaic technology.
Another big solar innovation is in integration. New generations of solar cells may be built into siding, roofs, windows, and more.
San Jose-based GAF Energy has developed a way to produce solar roofs that are installed just like regular asphalt shingles. These provide the same protection as shingles, can be nailed just like shingles, and don't create any added bulk. These solar roofs have the same aesthetic as conventional shingle roofs, too, and may be appealing to homeowners who object to the look of bulky, rectangular solar panels.
On another note, Redwood City-based Ubiquitous Energy has developed transparent solar panels that collect energy from the invisible spectrum. These are suitable for placing on windows or other surfaces that require a solution that won't block visibility.
Big, rectangular solar panels may soon be a thing of the past, and a lot of companies are banking on that. Not only are researchers and innovators looking for the next new material for harvesting solar energy, but they're also working on ways to recycle existing panels and reclaim the rare materials used in their manufacture. In the near future, we may see old-style solar panels completely replaced with efficient and unobtrusive solar roofs, siding, windows, and more.
