After Going Dark, GMZ Energy Plots a Comeback on Waste Heat

GMZ Energy made a bet on solar energy and lost. Now, its fortunes lie in convincing industrial companies to put its power-producing devices into their products.

The Waltham, MA-based company traces its roots back to the labs of MIT and Boston College where researchers developed ways to improve the performance of thermoelectrics—materials that produce electricity when exposed to a source of heat. The company received three rounds of funding, totaling about $20 million over seven years.

With GMZ Energy’s Series C round in late 2011, the company had plans to use its thermoelectric modules with solar collectors. The idea was that solar tubes or panels that collect the sun’s heat would produce not only hot water but also electricity using GMZ’s technology.

But by late 2012, the company realized that it needed to shift gears, says CEO Cheryl Diuguid, who joined the company last year. The prices of solar electric panels dropped dramatically in the late 2000s thanks to a massive run-up in Chinese solar panel manufacturing, making solar thermal technology less competitive. It also made GMZ’s thermoelectric devices less compelling since they were designed for the relatively low-temperature heat of solar collectors.

“It was a brave decision because when the solar market turned around, they literally stopped that product,” says Diuguid. “Fortunately, the team had already moved down the path to high-temperature waste heat.”



The pivot required the company to choose a different class of thermoelectric materials, called half-Heusler, and target a different set of customers. By modifying the chemical composition of the material and using the founding technology, engineers have been able to improve the performance of the half-Heusler materials, Diuguid says. Earlier this year, the company also brought in a new vice president of development, Scott Rackey, who has experience in energy startups.

Most importantly, GMZ has released a product and, as of last week, a second device that boasts better power performance. Its modules look like a coin-size square plate and are sandwiched between a heat sink and a cold plate to produce electricity from heat.

The fact that GMZ can sell products to other companies for testing is significant because the field of thermoelectrics has been caught in academia for decades. What has been needed isn’t just technical improvements in converting heat to electricity, but also finding suitable applications.

Alphabet Energy, another thermoelectric startup which is based in Hayward, CA, spent years refining its product and choosing target customers. It ultimately decided to design a thermoelectric generator for heavy industries, such as mining and oil and gas. It, too, switched materials along the way. Alphabet released a complete generator based on its thermoelectric devices yesterday, its first product.

GMZ Energy’s product works best at temperatures between about 400 degrees and 600 degrees Celsius, which makes it well suited for converting the waste heat from boilers, diesel generators, industrial machines, and vehicles. A Department of Energy grant is paying for GMZ’s modules to be tested with Honda, which, like other automakers, has been studying thermolectrics for years. The goal with the Honda research grant is to generate about 200 watts from the car’s exhaust system to offset the power generated by the alternator at a cost of about $1 per watt, says Diuguid.

The auto industry needs new technologies to meet fuel efficiency mandates, but it tends to move slowly—the best-case scenario for GMZ Energy is to get its modules tested in cars by 2018 or 2019. But the company has joint development agreements with companies in other industries that could lead to commercial sales in late 2015 or early 2016, Diuguid says.

“We are out of the lab,” she says. “We’re not doing some funky little bench-top lab test. We’re putting our products in simulations of actual products or the actual product itself.”

To get closer to commercialization, GMZ Energy will need to raise additional funds from “strategic” investors, which could use their technology, as well as venture capitalists, says Diuguid. Current investors include Japan-based Mitsui Ventures, I2BF Global Ventures, BP Alternative Energy, and a joint venture of General Electric, NRG Energy, and ConocoPhillips. Kleiner Perkins Caufield & Byers was a seed investor.

In theory, there’s lots of potential in thermoelectric devices since they have no moving parts and turn a waste product—heat—into something valuable. In cars, for instance, it’s estimated that more than half of their energy in their fuel is lost to heat. But no company has been able to turn that promise into a commercial product with wide appeal (thermolectrics are already used in some niche applications, such as portable coolers.)

For GMZ Energy, which has survived despite at least one major miscalculation, the question is whether it can demonstrate what no one else has: a thermoelectric product that generates not just a flow of electricity, but rapid revenue growth as well.

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