Three years ago, Bill Davis and a group of five engineers and scientists began brainstorming ways to reduce greenhouse gas emissions and create clean energy.
“We came to the conclusion that, in the U.S. alone, we landfill hundreds of millions of tons of benign solid waste,” Davis recalled. “For every ton that gets landfilled, 1.8 tons of CO2-equivalent greenhouse gas gets emitted over the life of the landfill.”
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“If you could prevent the gas coming off the landfill, that’s a good thing,” he added. “And if you could repurpose that gas into electricity, you’re solving two problems: You’re helping to solve the environmental problem and you’re creating distributed energy, so you’re offsetting the need for fossil-fuel energy.”
That is what Ze-gen Inc. was created to do – or rather, to figure out how to do effectively.
Now, the Boston-based company has secured $2.25 million in financing from a syndicate of investors led by the quasi-public Mass. Technology Development Corporation to build a 1,600-square-foot “proof-of-concept” facility in New Bedford.
“We’re hoping to start building in late 2006 or early 2007,” said Davis, the company’s president and CEO. “A lot of our equipment is already sitting [in Boston] and waiting to be installed, so it will only be a three-month construction process.”
Though the facility, at the New Bedford Waste Services site on Shawmut Avenue, would only be a prototype, it still could handle up to 100 tons of construction and demolition waste a day.
In theory, there is no reason the facility couldn’t also take in municipal solid waste or household trash, Davis said, but that won’t be tested right away.
The project will rely on gasification – the conversion of a solid to a gas, through a chemical process – to accomplish its goals. Though refuse gasification is already being used, primarily in Asia, Davis said, many of the existing techniques have not yielded very impressive results.
“In the spring of 2004, we researched a bunch of technology – and while there are gasification processes out there, none are efficient,” he said. “They have energy going in with the trash, and then the system is consuming energy and reprocessing it, so there’s energy coming out. But if there’s a lot of surface area, then there’s a lot of heat loss, and if the system involves multiple processes, each is consuming energy.”
Because of these and other design issues, the output of energy in such systems is minimal and not cost-effective, Davis said.
“At the end of the day, they’re making a little electricity, but they’re still depending on high prices for the waste, because if you’re only selling a little electricity, then you’d better be getting a lot for taking the waste,” he said. “The problem has been the economics.”
Davis said he believes the economics are a problem because gasification, despite its benefits, has not yet taken off in the United States. But the hope is that Ze-gen’s model, using proven technology as well as new technology developed by the company, will take off.
“Were trying to put efficient process improvement into all aspects of the overall gasification process, in order to generate large volumes of synthetic natural gas,” Davis said. “If we can do that, we can generate large revenues from the electricity and be less dependent on [revenue from] the waste coming in.”
Davis said a full-scale facility could generate 1.6 megawatts of electricity per ton of waste, or 30 megawatt hours per day – roughly, what 30 Rhode Island households would consume in a year. First, however, the proof-of-concept facility will gauge for six months how much gas it can generate per ton of waste, to verify the model.
“If we generate the test data we think we will generate,” Davis said, “we’d then look to site availability and funding.”
Though New Bedford “would be an option” for a permanent site, Davis said, any other site that meets certain criteria would also be considered. “The places we’d be interested in building would be where there are high energy costs, high tipping fees and a municipality that’s receptive.”
As for the proof-of-concept facility, he said, it would probably be moved to a permanent site, to be used as a research and development facility.
