Rethinking the battery

 By Erin Biba

A team of Berkeley engineers and scientists at a company called Alphabet Energy are taking an old idea (thermomeletric energy) and figuring out a new way to harness it to produce clean energy. Erin Biba looks at the long history of thermoelectric energy, what the science is behind it, and how Alphabet Energy is hoping to use new technologies to harness waste heat, which they call “one of the greatest untapped resources that we have”…

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It’s really a very old idea. The concept of using heat to generate electricity is something scientists and engineers have been tinkering with since the early 1800s. But they never really got the hang of it and science hasn’t been able to make it all that efficient. For the most part, thermoelectric energy finds a home today in places that don’t need large amounts of energy — like out in deep space where devices like the Mars Rover use nuclear material to generate heat that is converted into energy. But Alphabet Energy, a startup out of Hayward, California, is hoping to change that by rethinking the thermoelectric generator and recycling waste heat in the process.

A thermoelectric generator works by capturing the energy created when a hot material cools. It’s called the thermoelectric effect and it’s created by electrons. It works like this: If you heat one side of a metal object and cool the other side, the electrons in the object start to move around. On the hot side, the electrons will have more energy — they’ll move around very quickly. On the cool side, the electrons will be more lethargic and less excited. That means the electrons on the heated side will move more quickly towards to the cold side of the object. As they move, the hot end of the object becomes positively charged and the cold end becomes negatively charged. The object behaves a lot like a battery with a + on one end and a – on the other. Simply heating and cooling the object at the same time generates electricity.

Waste heat is valuable

It seems like a simple and easy way to generate power, but it’s not very efficient. The amount of power this temperature change creates is very small, so you need a lot of materials connected together to make a useful amount. On top of that, the materials that are great at generating electricity are also much better at conducting heat then they are cold — so they don’t create a charge for a long period of time.

But Alphabet Energy is addressing the thermoelectric conundrum by creating materials that use nanotechnology to make the electric charge more efficient. With 60 patents and development from scientists at Lawrence Berkeley National Laboratory and Michigan State University, they have figured out how to make a higher-powered generator and battery system that finally makes thermoelectricity work on a large scale without costing an arm and a leg. That breakthrough might seem exciting on its own, but the real leap forward in the technology is the fact that the heat used to power their systems is taken from waste heat generated by engines.

Their batteries, called PowerBlocks, use thermoelectric material (built using nanotechnology) to collect heat generated by engine exhaust and transform it into power. In other words, the PowerBlocks can capture the heat that, say, an oil drill’s engine makes while it runs and store that energy for later use. So a company that uses the device benefits by basically re-using their own energy. The power that goes into moving an engine gets recycled, via heat output, into batteries that can be used to re-power those engines. And Alphabet can also link a whole series of these PowerBlocks together to harness more (or less) energy depending on the needs of their customers. It’s easily scaled.

The company currently has customers from energy-intensive industries like oil and gas, mining, manufacturing, and transportation using their devices. These are areas that generate massive amounts of heat in the process of their daily business and for the most part that heat is wasted — it dissipates into the sky without being used. In fact, traditional power stations lose about two-thirds of all the heat they generate into the atmosphere through their cooling towers. It’s easy to imagine the possibilities when it comes to energy generation and storage if those power stations could take all that lost heat and turn it into electricity.

And speaking of possibility — Alphabet is looking beyond its current core customers and forward to the automotive industry. They’re hoping to make cars more sustainable by capturing the heat from a car’s engine that is sent out through the automobile’s exhaust. They’re currently developing a device called the PowerCard, which is a commercially viable heat-charged battery. That means it may not be all that long before manufacturers can start installing these batteries into consumer cars and turn the very act of driving into its own method of recycling.

about the author
Erin Biba
Erin Biba is a freelance reporter and Correspondent for WIRED Magazine. Based in San Francisco she covers science and its intersection with technology and pop culture.