Rise of the Portables

Small-scale power solutions tap into waste streams and local biomass.
By Chris Hanson | July 01, 2013

Propagated from R&D labs, think-tanks and even art communities, portable biomass power units have the ability to generate energy for a diverse set of applications and users. By providing a sundry of industries and communities with power, portables are comparable to other distributed power options, such as solar and wind. From California to New York and up into Canada, companies are finding creative solutions to the technological challenges surrounding portables.

Nestled in the Bay Area of Berkeley, Calif., All Power Labs is the offspring of the art world. Tom Price, evangelist of the company, says local artists experimenting with large-scale pieces of industrial sculpture that incorporated fire elements spurred the research into gasification technology. The first biomass unit was constructed in 2007 and was a last-minute feature at the CleanTech Open.“That’s how we found ourselves in the fire lane of the center crowd of the convention center,” recalls Price. “The gasifier running, made out of junk, with all these VPs and CEOs standing around with their jaws on the floor, because we had just made the thing they were trying to invent—basically for free.”

After open sourcing its technology in 2008, the lab developed its PowerPallet technology. Currently, the lab is offering two sizes, 10 and 20 kilowatts (kW), at the average cost of $1.50 per watt. Both units stand only 6 feet high and have a footprint the size of a standard shipping pallet. Price says keeping the project small scale forced them to creatively integrate the components, and enables users to easily transport the unit to be used for rural electrification, off-grid homes and similar applications.

The units can operate on a variety of feedstocks, with a preference for hardwood, softwood, and nut or coconut shells. Systems to handle additional feedstocks, including poultry litter and straw, are in development. At 75 percent load, the 20 kW unit’s General Motors Vortec engine will consume roughly 952 pounds of biomass to generate a power output of 360 kW-hours.

With installations in 45 universities in the U.S. and elsewhere, and in 30-plus countries, demand for the power technology has been increasing. Price recently visited with a representative from Africa interested in testing more than 240 units in trial villages. Many developing countries have incomplete electrical systems and several war-torn places have damaged systems, says Jess Hobbs, All Power founder. “There’s a general trend towards approaching energy from a microstructure. That’s another important reason we developed our trial-scale systems.”

Waste Heat and Power

In Great Neck, N.Y., AgriPower Inc. also manufactures portable biomass power systems. Barry Berman, AgriPower CEO, says the project began in 2002 with the development of a heat-only unit that was deployed in schools, hospitals and prisons for hot water production. A combined heat-and-power module—the waste heat generator (WHG)—is the product of research and development within the past two years. The biggest challenge of the design was solving a combustion chamber issue, according to Berman, as the initial gas-powered turbine used did not mesh well with the WHG combustion chamber’s performance. The turbine was designed for immediate operation, whereas the chamber needed time to heat up to operating temperatures. Altering the turbine design solved the problem, says Berman.

Unlike All Power Lab’s pallet-sized unit, AgriPower’s system is twice as tall and stretches about 40 feet once assembled. Because of the size, the heat and power units are transported separately via truck, then assembled and in operation within three to five days. The units are designed to provide baseload power to whatever application is used, lessening the amount of power needed from the grid.

Once in operation, a 375 kW system will consume roughly 15 tons of fuel, depending on composition, density and moisture content, for 24 hours of continuous use. The system can be fueled by wood residue, crop and animal wastes and operates between 1,000 and 2,200 degrees Fahrenheit.  During emission tests of the Agri-Power combustor, the unit consumed more than a ton of shredded wood chips with 40 percent moisture content, while emitting only 1.47 pounds per hour (lb/hr) of particulates with less than 0.20 lb/hr of carbon monoxide. 

Demand for the units is growing, and Berman says the company is getting ready to ramp up production. He has been contacted by both domestic and international organizations and businesses interested in using them. One interested company in remote, northern Canada could potentially save $1.6 million each year in carting and disposal fees, he says, by using discarded wood and food waste in the portable unit. In addition to powering remote locations and villages in developing countries, Berman says some government agencies, such as the Federal Emergency Management Agency and Homeland Security, have shown interest in the units. Debris from natural disasters could be used as fuel to power emergency electrical generation and water purification.

Containerized Solution

Canadian-based EverGreen Energy Corp. has a 50 kW portable biomass power unit capable of using a medley of feedstocks. “We are fortunate that we have a list of waste streams that we can take, from woodchips, to slash, biodegradable municipal solid waste, some manure and woodchip mixes, corn, miscanthus, and other energy crops,” says President Garry Spence.

When evaluating a project, the company assesses available waste streams. Spence says the unit can utilize fuels with 10 to 40 percent moisture content, with 20 percent being the sweet spot.
EverGreen units are shipped from the manufacturer in 40-foot containers and picked up from the plant by truck to be transferred to rail or trucked to their final destinations. Spence adds that for remote locations, units can travel via multiple shipping modes. “So much of the energy that has been used by different remote areas is diesel-electric,” Spence says. “Nothing against diesel-electric, but we can replace that with biomass. But you have to have biomass available and you have to have the technology that can be positioned. So that’s why we like the containerized sizes, so they can be easily delivered.”

Future Applications

Henry Quesada-Pineda, assistant professor of sustainable biomaterials at Virginia Tech, believes there are both environmental and cultural implications for portable biomass technologies. He says utilizing renewable resources, such as biomass and agricultural wastes, will help alleviate waste management concerns for remote locations and could offset methane produced from decaying crop residues in developing countries. He adds that the unit the college is currently testing works well with hardwood and softwood fuels, but newer units will need to utilize a broader variety of feedstocks. Some, such as chicken litter, will require developing additional processes to turn the waste into a viable fuel.

In addition to environmental benefits, Quesada-Pineda foresees cultural benefits from using portable biomass units. One of his proposals to the college involves transporting a few portable biomass power units to Central American countries such as Costa Rica and Guatemala. “We tried to tell them we can help you to understand that waste can actually be a value-added product and for them it’s kind of surprising,” Quesada-Pineda explains. “I think it’s mostly because in most cases they lack the access to the knowledge.”

Increasing public awareness and overcoming inaccurate perceptions is perhaps the biggest obstacle restraining future market growth. To overcome this challenge, Berman seeks out speaking engagements and attends trade shows to demonstrate AgriPower’s abilities. Spence says developing more cost-effective technology will generate more interest among potential users. Price sums up his vision for future applications of portable units this way: “I don’t think it’s up to us to decide. What we’re trying to do is create the opportunity for people to empower themselves.”

Author: Chris Hanson
Staff Writer, Biomass Magazine