Poultry litter to power
By Paul MacDonald
By Paul MacDonald
A new $200 million
poultry litter-to-power plant—the first of its type in the United
States—is starting up in Minnesota in a few months’ time and will give
that state’s turkey growers an option to spreading, with litter removal
only a phone call away.
A new $200 million poultry litter-to-power plant—the first of its type in the United States—is starting up in Minnesota in a few months’ time and will give that state’s turkey growers an option to spreading, with litter removal only a phone call away.
Turkey growers in Minnesota are going to have another option for managing their litter—besides spreading—later this year, and that option will literally be only a phone call away.
“All the turkey growers have to do is call me, and we’ll send some trucks over and take care of their litter for them,” says Greg Langmo, fuel procurement manager of Fibrominn, the new $200 million poultry litter-to-power plant in Benson, Minnesota.
“Once they’ve phoned us, they should get their loader out because our trucks will be on the way,” he adds.
Langmo knows all about the challenges poultry growers face in Minnesota, being a third generation turkey farmer. He was also part of a local effort that was instrumental in getting the Fibrominn plant in the state.
Back in 1998, Langmo contacted Fibrowatt LLC, the US company founded by the British management team which built the world’s first three poultry litter fueled power stations in the UK, to see if they would be interested in locating a poultry litter-to-power plant in Minnesota. Much hard work followed over the next half-dozen years. But fast forward to 2007, and the first litter-powered plant in the US—Fibrominn—is scheduled to start up this spring. The last stages of construction are now being wrapped up by SNC-Lavalin, which built the plant on a turnkey basis.
Like many parts of the country, agriculture in Minnesota has seen tremendous growth through the 1990’s and into the new millennium. And, again, like other areas of the US, the nature of the industry has changed, with larger operations now being the norm, particularly in turkey production. Minnesota is the top turkey producing state in the US.
“The industry has been very successful in Minnesota,” explains Langmo. “We saw rapid growth and some large processing facilities, such as Jennie-O, expanding in the state.” With that, of course, came larger turkey farms—and lots of litter to be spread on the land, including around the town of Benson.
The poultry growing region of west-central Minnesota, however, is only about 75 miles from Minneapolis/St Paul, close enough that Twin City residents have purchased recreational property in the area. “Land was fairly inexpensive, and people thought that any piece of land with a slough on it would be a great place to build a house,” says Langmo.
But these city dwellers did not take kindly to all the manure being transported and applied—regardless of the fact that all these farms were there first. There was political pressure on local government.
“In our county, they called in members of the local poultry industry and told us that we have a problem—and that we needed to fix it or they would fix it for us,” says Langmo. “Their idea of a fix was an absolute loser for us as farmers—we would have to put in separate storage buildings, concrete floors, all this for a product that had limited market value. As the saying goes, we had to take the bull by the horns. There had to be a better way.”
Many of the better ways seemed to address the problems of litter on a small scale, or piecemeal basis, such as composting on individual farms. “The large concentration of birds seemed to lend itself to a large business model so the commercial scale of Fibrominn seemed to fit well with the nature of the business in Minnesota.”
The planning process for the Fibrominn plant was extensive and involved building in sufficient time to receive the necessary permitting, explains Terry Walmsley, environmental affairs manager for Philadelphia-based Fibrowatt LLC, the US-based parent company. “We were able to do a number of our permits in parallel and, apart from a lot of extra air dispersion modeling we had to do for our permit, things went very smoothly.
“We were helped by the fact that our team had a lot of experience permitting facilities in the UK, as well as some really good operating experience there. These components really helped us with the environmental permitting process for Fibrominn.”
|The Fibrominn power plant (pictured above under construction) will collect litter from about 300 separate turkey producers—everyone from the major growers to small mom-and-pop operations—using it as fuel to generate 55 MW of electricity.|
Having been down this path before, Fibrowatt invested a good deal of time making sure local people understood how the plant would work, and that it would have extremely tight environmental controls.
“A Citizen’s Advisory Panel was set up early on and met almost on a monthly basis, once the site was identified,” says Walmsley. “The panel turned out to be a very instrumental part of the comfort people in the local community had towards the Fibrominn facility.”
Langmo spoke on behalf of the project to local service groups, the media, politicians at all levels—and others involved in agriculture. “I met with the Minnesota Milk Producers Association and explained what the project was all about. They liked the idea because it would open up more land for spreading by their dairy guys. Fibrominn could be considered to be a big win for everyone in the ag industry in the state.”
The project provides local turkey farmers with an important, and viable, option for handling their litter, aside from spreading. And judging from the response, Langmo can expect to be getting a lot of those litter pick-up phone calls. Fibrominn has already signed long-term litter supply contracts with a number of growers. “It’s easy for them—they phone us up and tell us they are going to have a thousand tons or whatever ready to go, and when they want us there,” says Langmo.
Contract trucks are dispatched on the appointed day and are loaded up by the farmer, with the litter contents carefully contained. All the drivers are trained in the proper bio-security procedures.
At the plant, each load is weighed, and trucks back into a large enclosed area where their loads are discharged. “The building is kept at a negative pressure, so no odor will escape,” explains Langmo. “There will be large amounts of litter on site all the time, but there will be no outside stockpiling, so our neighbors should not smell us.”
The negative pressure is achieved by taking the air needed for fuel combustion from the fuel hall, creating a constant flow of air in from outside, which prevents odors from traveling in the opposite direction.
Before trucks leave the plant, they are washed and disinfected in an innovative truck wash building, utilizing building technology from Octaform. Their building system uses PVC to encapsulate concrete walls, keeping the building clean, waterproof and long lasting—unlike other materials, it will not rust, rot or attract mold and mildew. The PVC cladding resists the harsh chemicals and the wet dry cycles involved in the washing and disinfecting of dozens of trucks every day.
“Everyone in the industry, regardless of whether you are poultry, hog or dairy, is concerned about bio-security, and rightfully so,” says Langmo. “This system raises the bar and lets the grower know that our trucks are being cleaned and disinfected every time they leave our plant.”
The company has been working on sampling the litter and developing a database of its fuel quality—essentially tracking the amount of moisture in the material they will be receiving. “We’re treating the litter material from a value perspective as a fuel,” explains Walmsley. “And the lower the moisture in the litter, the more value it has to us as a fuel, and the more value we can provide to the grower. We provide the growers with an incentive for the highest quality litter, building this into the contracts.”
Although they are working with the growers to get as much dry litter as possible, Walmsley says Fibrominn fully understands that the company is in the business of servicing its suppliers—and working with the litter they receive from the turkey producers, regardless of its moisture content.
“We recognize that in providing service to the grower, we have to provide them with something they value. And that value is the ability to take what they produce, and to be able to service them based upon their needs, not our needs. And while we provide incentives to the growers, we’ve designed a plant that can handle variability and be flexible, as seasons and suppliers change.”
Fibrominn is also an option available on a year-round basis—regardless of what is going on with the weather or what season it is, they will be accepting litter and producing power.
Plans are to collect litter from about 300 separate turkey producers, everyone from the major growers to small mom-and–pop operations. “We’re happy to work with all of them,” says Langmo. “We can essentially burn whatever they have their birds on.”
Since there is going to be a range in the quality of the material, they are working hard to make sure they have a handle on that. “From our experience in the UK, we know that you have to properly understand the market that you are working in—that’s why we’ve done a lot of sampling and testing, to get a full understanding of barn management practices,” says Walmsley.
“We’ve been able to design a plant that was right for the Minnesota market. In many respects, it looks like the plants in the UK, but you could consider it third generation technology.”
Once it’s inside the plant, wet material is segregated with other wet material, and dry material with other dry material. “From there, it is transported by crane and stored in what we call virtual lanes—these are long piles of wet or dry material,” explains Walmsley. “From that, we are able to formulate a fuel so we can keep a pretty consistent quality of material going into the boiler.”
Screening and removal of lumps is carried out to give litter the more typical boiler fuel material characteristics. Walmsley notes that while they work hard to sort and size the litter into good fuel material, it is not ideal fuel material. Like any biomass, litter presents challenges in that it has a fair degree of variability, moisture and ash content. But with the experience of its parent company, staff at the Fibrominn plant know how to best manage these challenges. “There’s nothing like experience and dealing with past challenges to provide you with the right approach.”
The right approach will also include a fuel formula that incorporates some secondary biomass. This could be wood shavings, sawdust, alfalfa stems or corn stover, which aids both in moving the material and its combustibility.
From the storage hall—which holds between five and 10 days worth of fuel—fuel is conveyed into the boiler via a mechanical distribution system. Air from the storage hall is drawn into the furnace by fans and is used as the combustion air within the boiler. The temperatures will reach in excess of 1,500 degrees Fahrenheit, destroying any odor and bacteria.
The plant has a single, conventional boiler design with a feed system and grate specifically designed to combust poultry litter and other biomass fuels.
Boiler combustion air obtained from the fuel storage building is preheated for use as primary and secondary air. The preheated primary air is fed under the grate, and preheated secondary air is injected at strategic locations above the grate. The boiler combustion chamber or furnace is made up of water-wall tubes.
High pressure steam produced in the boiler is used to produce electricity in a condensing extraction turbine generator. The steam is condensed back to water using an air-cooled condenser. Such a condenser was chosen based in part on Fibrominn efforts to minimize water usage in this dry northern prairie location.
Generating 55 MW of electricity, the plant will be connected to a new 115 kilovolt power line that will run approximately a quarter of a mile to a major substation owned by Great River Energy. Fibrominn will sell its output to Xcel Energy under a 21-year power purchase agreement which has been approved by the Minnesota Public Utilities Commission.
Ash from the combustion process is collected in containers and hoppers before being conveyed elsewhere for conditioning. “We’re going to be left with a high nutrient ash,” says Walmsley. “While it may lose its nitrogen content, it retains all the phosphorous and potassium as well as secondary nutrients and micro-nutrients. It can be of substantial benefit for re-use, allowing farmers to meet agronomic application rates in a little easier way because of its concentrated nature and ease of field application.”
Parent company Fibrowatt LLC now has a pipeline of new projects under development in poultry growing states across the US, including North Carolina, Maryland, Arkansas and Mississippi. As with Fibrominn, the economics of these projects are looking more attractive thanks to big increases in the cost of conventional fossil fuels in recent years, although biomass brings its own considerations as a fuel.
“Biomass will always be a bit of a challenge,” says Walmsley. “It’s much easier to bring in natural gas or coal, which are high energy density fuels versus biomass which is low energy density.” Depending on the moisture content of the litter, coal, for example has at least twice the fuel value of litter on a pound for pound basis.
But there are other factors at work such as the impact of fossil fuels on global warning. There’s do doubt that setting up an electrical power plant that burns litter—and has little impact on the environment—was a much easier sell in environmentally-conscious Minnesota than a coal burning power plant.
And then there is the appealing cost of litter as a fuel. “As the cost of conventional fuel continues to go up, and with the cost of litter being relatively stable and the supply steady, we think we will become a very viable, very competitive approach in electrical generation,” says Walmsley.