Waste to energy shows potential

Waste to energy has come a long way, with plenty of clean choices commercially available now.

But while the industry may have matured, there are still growing pains to come, according to a "Waste to Energy, Progress and Potential" forum in San Francisco last night.

Just 15 to 20 years ago, the industry was synonymous with mass incineration, with many facilities being built simply to reduce the volume of waste and not necessarily for the production of electricity, and without the pollution controls available today.

"The fact we can talk about this as an investment opportunity without irony shows how far we've come, or how easily we can forget," said Sanjay Wagle, VP at VantagePoint Venture Partners.

VantagePoint has stakes in Stockholm's Chemrec and Boston-based Ze-gen, both gasification waste-to-energy companies.

Cash may be flowing into these new technologies, but widespread use is still a stumbling block.

According to presenters, California alone produces more than 60 million dry tons of organic waste per year, with a potential energy content of more than two gigawatts.

From left to right, Necy Sumait and Christopher Scott of BlueFire Ethanol, Dave Konwinski of Onsite Power Systems, Doug Williams of BioEnergy Solutions, Sanjay Wagle of VantagePoint, David Albers of BioEnergy and moderator David Wheat >>

Only about one million tons of that are being converted to energy, mainly by combustion, generating just a few hundred megawatts of power.

One potential untapped source is cow power. Bakersfield, Calif.'s BioEnergy Solutions turns animal waste into biogas for power generators, selling the gas primarily to San Francisco-based utility PG&E.

"There's a lot of interest in this sector," said David Albers, president of BioEnergy.

California has about 2,000 dairy farms, with an average of 850 cows on each one. Those cow pies are breaking down and producing methane.

But instead of letting it all go into the atmosphere, BioEnergy is capturing the waste in a sealed holding area that accelerates and increases the bacterial activity, collecting the biogas equivalent of 100 gallons of gasoline per year for every cow.

BioEnergy, which has a system set up on Albers' own 3,400 cow dairy farm in Fresno County, has an agreement to provide up to 3 billion cubic feet of biogas a year to PG&E, enough to generate electricity for 50,000 homes.

Food plants also pump out plenty of leftovers. A typical food plant produces about 12 garbage trucks a day full of organic waste, according to David Konwinski, founder and CEO of Davis, Calif.-based Onsite Power Systems.

Onsite Power is an anaerobic digester company that uses technology developed at the University of California, Davis.

Konwinski said food plants can't stay in California because it's getting too expensive to dispose of their waste.

Onsite, which has a demonstration facility in operation at UC Davis, uses bacteria to break down solid matter without any preprocessing, converting it into biohydrogen and biomethane.

Urban trash, rice and wheat straws, wood waste and other agricultural residues can also be turned into energy, according to Irvine, Calif.'s BlueFire Ethanol.

California uses one billion gallons of ethanol a year, but currently produces about 70 million gallons, importing most of what it needs, said Necy Sumait, Sr. VP and director of BlueFire.

BlueFire, which wants to bring the production of ethanol closer to the coastal cities where its needed, has a pilot plant in Southern California that uses concentrated acid hydrolysis. The company doesn't use any enzymes in its process, giving it feedstock flexibility.

Small, developing companies aren't the only ones working to turn waste into energy, Houston-based Waste Management (NYSE: WMI) is also on the case.

The No. 1 waste services group in the U.S. announced plans earlier this month to double its landfill gas to energy plants and more than double the amount of recyclable materials it processes by 2020 (see Waste Management to boost recycling, waste to energy).

Landfills generate methane, which, when released into the atmosphere, has a more damaging effect than carbon dioxide.

Moderator David Wheat of GCF Associates said there's an estimated 50 terawatt hours of untapped potential in landfills in California.

That's just a small part of the current 1,000 terawatt demand in the state today, but he said any time you turn methane into something else, you're doing something good for the atmosphere.

Even with these new technologies reducing the bulk of waste into energy, there's still a certain amount that can't be used, but that's not always a bad thing.

Doug Williams, chief technology officer of BioEnergy, said, "Nutrients left over is exactly what farmers want, so they can recycle them on their crops. That's why we're leaving our facilities with farmers."

The panel was organized by the MIT Club of Northern California Clean Technology Group.

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