Alphabet Energy’s tetrahedrite material is exceptional at converting waste heat to electricity (via AE)
Thermoelectric materials are great at turning temperature differences into electricity by utilizing the flow of electrons from warmer areas to cooler ones. Simply put, they turn ‘waste’ heat into an exploitable power source. The one problem that stands out for most thermoelectric materials is that they excel one area, either as a great heat conductor or a good electrical conductor, but not both. Those that are efficient at both tend to be rare, expensive to manufacture or incredibly toxic to the environment (lead telluride, bismuth chalcogenides, etc).
Tech startup Alphabet Energy (an offshoot of UC Berkeley) has found a viable alternative material that is both efficient at turning heat into electricity and will not be detrimental to the environment. The material is known as tetrahedrite, which is a naturally occurring mineral and is actually akin to copper and other associated metal ores. The ore is also cheaper to use, as it does not require the extensive manufacturing process to produce and is fairly abundant compared to the traditional materials currently in use. The fact that tetrahedrite can be synthesized as well as mined also makes it a boon for large-scale thermoelectric generators, which are not a viable option using materials such as silicides or sodium-cobaltate.
So, why is using the material for thermoelectric generators a big deal? Well, first off, the majority of the electricity generated all over the world is heat-based. Coal, nuclear and natural gas all generate electricity through heat energy and operate at a 30-40% efficiency and in the process bleed about 15-terrawatts of power (heat loss) to the environment annually. In 2006, the world consumed roughly 16-terrawatts of power over the course of a year, so it is safe to say that the amount of power lost is staggering.
Massive thermoelectric generators could reclaim some of that heat and convert it to useful electricity but the feasibility to do on such a grand scale was not possible until now. In fact, according to Alphabet Energy, the company plans to release their tetrahedrite material to the market later this year for stand-alone generators, however they plan on working with car companies to see if they can develop a solution to harness heat from vehicle exhaust systems. The company also claims major advancements in silicon nanowire-based thermoelectrics that can be incorporated into macroscopic materials (obviously not for large-scale plants) for use in small mobile devices and other platforms. Suffice it to say, it will be interesting to see what becomes of Alphabet’s endeavors in the coming years.
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