By Guest Blogger Ryan McNeill
For decades, solar energy has been an industry shaped by revolutionary, new technology, growing by leaps and bounds in the most unpredictable ways. The boundaries of solar technology are always expanding, and as we make our way deeper into 2013, it’s clear that this year is shaping up to be perhaps the most exciting one yet. While there are a number of advancements being made, there are three that stand out as particularly promising:
Record-Setting Efficiency for Cadmium-Telluride
With a natural advantage over other materials, cadmium-telluride (CdTe) responds differently to sunlight thanks to its superior temperature coefficient, giving it the ability to produce more energy than systems with the same power rating. Following extensive R&D investments, Ohio solar company First Solar has achieved record-setting efficiency for CdTe photovoltaic solar cell conversion. Up from their 2011 record of 17.3% efficiency, First Solar has pushed the envelope even further and reached 18.7% in tests that were confirmed by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL). While it will be a few years until this level of efficiency is available to consumers, there’s no doubt that it will affect the future of the industry.
Pushing Multi-Junction Technology
Another advancement in efficiency lies in multi-junction technology, which currently boasts a record of 44% efficiency. That may sound impressive, especially when compared to traditional silicon solar cells’ current limit of 25% efficiency, but the U.S. Naval Research Laboratory has their eye on an even more ambitious prize: 50% efficiency. The key to this success lies in the scientists’ identifying “InAlAsSb quaternary alloys.” This high gap band material can be grown lattice-matched to an indium phosphide (InP) substrate, which together achieve a direct band gap of 1.8 electron volts (eV). As with CdTe solar cells, this new technology isn’t ready for commercial production, but thanks to funding from the U.S. Department of Energy (DoE) and the Advanced Research projects Agency-Energy (ARPA-E), scientists at the Naval Research Lab will partner with MicroLink and the Rochester Institute of Technology to develop the technology over the next three years.
This advancement has to do with another kind of efficiency: materials. Publishing their findings in December’s Scientific Reports magazine, Stanford University scientists have developed a peel-and-stick solar panel, called thin-film solar cell (TFSC) stickers, that can be installed directly over virtually any material, no matter how uneven or curved. The benefits of this technology are obvious: installation costs would plummet, opening up the market to many new buyers who previously couldn’t afford the technology. Not only that, but solar could be applied to virtually any device, from coffee mugs to cell phones and even to business cards; the possibilities are endless.
The key to this achievement isn’t the fact that it’s flexible, though. It’s the fact that these TFSCs have the same level of efficiency as traditional solar cells, AND they aren’t cost-prohibitively expensive to produce like similar designs. So, how is this possible? Stanford’s design involves applying a layer of nickel over the rigid silicon wafer, and then using a revolutionary water bath technique to transfer the TFSC from its original Si wafer to the target. The Si wafer can then be reused for other stickers.
These three advancements in solar technology hint at the promise of great things to come. From increasing energy efficiency to reducing production materials and expanding applications, today’s achievements are clearly leading the way to a brighter tomorrow for the solar industry.
About the author
Ryan McNeill is the President of Renewable Energy Corporation, a solar panel installation company based in Maryland. Ryan has collaborated with the American Solar Energy Society, Sustainablog, Energy ViewPoints, Total Electricity and other solar industry experts.