Ze-gen Ramps Up its Waste Gasification Process: Lessons from a Clean-Energy Startup

Xconomy has been around for 27 months now, long enough to watch quite a few of our fellow Boston-area startups expand, deal with serious challenges, and start to get their technologies out into the world. One of them is Ze-gen, a waste gasification company that I first visited in August 2007. This week I got a chance to take a second tour of the company’s demonstration plant in New Bedford, MA, an hour south of Boston, and to get an update from president and CEO Bill Davis, who founded Ze-gen in 2004.

The tour and the interview turned into a mini-education in the hurdles facing startups in the bustling, bruising cleantech sector. So far Ze-gen has been clearing those hurdles, and if all goes according to plan, the company will have its first commercial gasification plant up and running by the second quarter of 2011. That’s about a year behind the schedule the company originally laid out back in 2004. But considering the state of the economy lately, a year’s slippage isn’t all that bad.

I thought I would try to sum up some of the insights from Ze-gen’s experience in digest form, which I’ve done below. But first, a quick refresher on Ze-gen’s business and technology. The company is developing an industrial-scale system in which organic waste material such as construction and demolition debris (called “C&D,” and composed mostly of wood) is dropped into a vat of molten metal. Under tremendous heat, the waste instantly breaks down into elemental gases—mainly a mix of hydrogen and carbon monoxide that’s known as “syngas.” The syngas can in turn be combusted to run electrical turbines or boilers, or turned into liquid biodiesel fuel. (Unlike incineration, the gasification process produces no carbon dioxide emissions; the name Ze-gen stands for zero-emissions generation.)

The feed hopper in Ze-gen's demonstration plant deposits feedstock (shredded wood waste) onto a conveyor.

The feed hopper in Ze-gen's demonstration plant deposits feedstock (shredded wood waste) onto a conveyor.

Ze-gen’s prototype system takes up a building the size of a large barn—and the commercial version will be even larger. The system was in full, hot, noisy swing during my visit. As the photos scattered through this article illustrate, the process is fairly simple, with shredded C&D waste falling from a hopper onto a conveyor and up an elevator, then falling back down into a furnace half-filled with a molten copper bath that’s maintained at about 2,400 to 2,700 degrees Fahrenheit. Syngas from the furnace flows out into a combustor—where the boiler or turbine would go, in a commercial plant—and leftover gases are scrubbed and vented.

Feedstock eventually drops into the gasification furnace, which is half-filled with molten copper.

Feedstock eventually drops into the gasification furnace, which is half-filled with molten copper.

Lately, Ze-gen has been running the plant for about 12 hours a day, gathering data on its syngas production efficiency using various types of feedstock, and at various bath temperatures. Getting to this point has been a five-year slog. “Any pre-revenue company, in my view, is frustrating, or should be frustrating, because it takes other people’s money in order to get a technology to the point where it’s producing,” says Davis. “For the first few years, at our demonstration plant, it was a lot of episodic testing. You’re not really ready for commercial deployment until you can prove that you can run continuously.” But Ze-gen now has the permits it needs to run 24/7, and as soon as the company can hire enough qualified staff, the gasifier will be running around the clock. “It’s actually quite satisfying, because I can come down here on any given day without making any special plans, and the plant is running,” Davis says.

The company has more than doubled in size since my last visit: it now has 27 staffers, 11 of them in an adminstrative and engineering office in Boston and the rest at the plant, which is conveniently located on the grounds of a solid waste sorting facility in New Bedford. All of that growth takes money, of course, and earlier this year, the company augmented a $4.5 million Series A round from 2007 with a much larger, $25 million round. The main funders include … Next Page »

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Wade Roush is a contributing editor at Xconomy. Follow @wroush

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