New technologies are fueling innovation in the waste-to-energy field. Two recent developments are set to bring projects online in North Carolina and Oregon based on taking agricultural waste and turning it into different kinds of energy.

In North Carolina, Charlotte-based electric power holding company Duke Energy recently signed a deal with Carbon Cycle Energy (C2e) to buy swine and poultry waste output from its facility planned for eastern North Carolina using the captured methane gas to generate renewable electricity at four power stations. C2e, headquartered in Boulder, Colo., will build and own the facility.

C2e will deliver more than 1 million MMBtus of pipeline-quality methane a year. Duke Energy should yield about 125,000 megawatt-hours of renewable energy a year—enough to power about 10,000 homes for a year. The renewable energy credits (RECs) generated annually will help satisfy state mandates for electricity produced from swine and poultry waste.

“One of the goals of the swine-derived biogas requirement in (Renewable Energy Portfolio Standard) REPS is to assists the North Carolina pork industry with development of ways to manage animal wastes,” says Thomas Mulholland, executive vice president of energy trading and risk management for C2e. “We are delighted that this project will do that, and in turn serve not only Duke Energy, but also the pork industry and the state of North Carolina.”

According to North Carolina's REPS, Duke Energy companies must meet specific compliance targets for swine and poultry waste. Duke Energy is already buying electricity generated from other facilities in the state.

“Under North Carolina’s renewable energy mandate, Duke Energy must generate 0.2 percent of its electricity from swine waste by the year 2021. This helps us along to comply with the goal,” says Randy Wheeless, corporate communications manager for Duke Energy.

Mulholland says C2e produces methane gas through a technique that mimics nature’s way of breaking down organic matter.

“Naturally occurring microbes present within digestive tracts of animals perform a biological decomposition process that converts biomass into methane, other gases and residual fibers,” he says. “C2e harnesses this process by installing digesters to do the same function—to convert biomass on a large scale into biogas. Downstream of the digester system, we purify crude biogas to meet to customer quality specifications, and inject it into a pipeline for delivery to Duke Energy.”

Mulholland says this approach can be utilized in many areas of the U.S.

“Some areas of the country have high concentrations of animal production, which can create large volumes of animal waste,” he says. “Our North Carolina project will use animal waste as feedstock for our digesters, making beneficial use of a resource out of place. We believe this approach could be applied widely.”

Duke Energy views this process as carbon-free energy, according to Wheeless.

“The air emissions from using the fuel at our plants are no greater than if the waste was left to decay naturally. That’s a good story, he says. “However, this process is more expensive than traditional sources. It’s even more expensive than renewable sources like solar power. Hopefully, new projects will bring the costs down.”

Mulholland says he sees the project as a win-win-win.

“The big benefit is to take a waste product, which we view as a resource out of place, and convert it into a useable fuel. By doing this, we’ll reduce harmful fugitive methane emissions, reduce odors, and reduce a part of Duke Energy’s fossil fuel consumption,” he says.

Farm Waste into Fuel in Oregon

Meanwhile, with support from the U.S. Department of Agriculture (USDA), Minneapolis-based Novus Energy, LLC will build a $20.2 million biorefinery in Boardman, Ore. to process agricultural waste into fuels, fertilizer and clean water.

Using waste from onion and potato processing plants, dairy manure, seasonal plant by-products and other waste supplied by local growers and processors as the primary feedstock Novus Energy plans to turn the waste into fuel, natural gas, organic fertilizer and other biobased products.

The biorefinery will be built on land owned by the Port of Morrow, one of the largest ports in Oregon.

Novus Energy’s proprietary technology, Novus Bio-Catalytic Conversion (NBC) System, is an integrated, bio-catalytic process that converts organic feedstocks to a variety of high-value products in one location. The process converts waste into valuable “green” products and recovers clean water while eliminating pollution caused by the burning and dumping of agricultural and organic waste.

The NBC process separates digestion products into clean biogas (hydrocarbons) and organic fertilizer (non-hydrocarbons and micro nutrients). The high-energy content biogas can be used as a fuel on site in lieu of fossil fuels or be further processed into renewable liquid fuels. The biogas is free from contaminants and does not require extensive cleaning.

And, the company already has a buyer for the biogas.

“We are working with BP,” says Burke. “They are in the market for renewable natural gas. We generate biogas, we compress it and clean it and convert it into renewable natural gas. We have an agreement with Cascade Natural Gas. So we’ll put into their pipeline and at the injection point, BP buys it from them and transports it to their customers.”

Novus Energy’s NBC gas production services use solid feedstocks, such as potato peels, straw, corn stover and sugar beet pulp, and forest products which, while abundant and inexpensive, are difficult to digest through standard anaerobic digestion. Many months are typically required to thoroughly digest these substrates. Burke says the NBC process digests these materials more completely and in much less time than traditional methods. The process enables a plant to realize significantly higher conversions in smaller volumes.

This is of great interest to potential buyers, says Burke. Following blind studies and a white paper on the technology, Burke says the reaction of potential customers was the same: “While it sounds great, where can I go see that?”

Novus then built a trailer that allowed it to take the technology to interested customers.

“Not only can you go see it, but we’ll bring it to you where we can operate it on your waste stream,” Burke says. “So that was the first demonstration plant on a mobile platform. And it was pretty unique.”

With the new plant, things will change. The Oregon plant will be the company’s first full-scale commercial plant.

Not only will it produce the biogas, but it also will use the digestate, a waste product of the process itself, to make a mineral-rich liquid natural fertilizer.

The initial buyer for the fertilizer is a Raymond, Wash.,-based company called Pacific Gro, which sells its own fertilizer products and distributes others.

“So they’ll use our fertilizer to enhance some of their products and sell it stand alone,” says Burke.

The new plant will act as an intercept plant for the Port of Morrow, where it will take a couple of waste streams from the port and giving them back cleaner water, he says.

“Today water as a commodity is cheap. Some day that will change and there will be more economic value for clean water,” Burke says.

USDA is supporting the project with an $11 million loan guarantee through the Biorefinery, Renewable Chemical, and Biobased Product Manufacturing Assistance Program, says Burke, which gives Novus Energy little risk on the loan. Novus is working with an Oregon lender, Old West Federal Credit Union, to finance the project. USDA hopes to finalize loan terms with Novus and Old West by summer.

“So depending on your equity to debt ratio, it establishes how much USDA will back, and in our instance they’ll back 90 percent of the loan.”

USDA has put its stamp of approval on the project.

“USDA is proud to support innovative, biobased projects such as this one,” Rural Development Under Secretary Lisa Mensah said in a press release. “This biorefinery will spur economic development, create new jobs and provide new markets for farm commodities in rural Oregon.”

On a daily basis, the plant is expected to generate 3.8 million cubic feet of renewable natural gas, 350 gallons of liquid fertilizer, and 11.2 tons of material that can improve soil physically or chemically to make it more suitable for plant growth. The facility also is expected to return approximately 172,000 gallons of treated water to the Port of Morrow daily. 
Novus Energy expects to hire up to 10 people to operate and maintain the plant and indirectly create another 15 to 20 support jobs. Burke says the company could break ground on the new plant this summer.