Pellet Properties

Economists exhort consumers to gather as much information as possible before making a purchase. But for those buying fuel pellets for residential or industrial heat, basic information such as heat content, ash and chloride can be hard to obtain. The Pellet Fuels Institute is helping pellet manufacturers create testing programs to help consumers know what they are buying.
By Jerry W. Kram
Caveat emptor. "Let the buyer beware." That hoary cliché of economics says that the consumer must take responsibility for knowing what he or she is buying. But it also assumes that the seller will make enough information available for consumers so they can make an informed and responsible choice. But what happens if the seller doesn't have the information the consumer needs? If that consumer has a choice between two products, one with a full analysis and one without, the seller who knows what's in his or her product may have a significant advantage.

That has been the situation in the fuel pellet industry, says Chris Wiberg, chief operating officer of Twin Ports Testing Inc. There has been a dearth of information generally comparing fuel pellets made from different feedstocks. Additionally, a significant number of pellet manufacturers have never had their products analyzed or have only had single samples of their products analyzed. Other energy sources such as coal, natural gas or fuel oil are standardized products that are consistent among many suppliers. With biomass fuel pellets, the properties of the fuel can vary not only with the type of feedstock but the time of year the feedstock was harvested.

Small Beginnings
The pellet fuel industry started in the early 1980s in response to the energy price shocks of the 1970s. The U.S. market has largely been limited to residential heating and fireplaces. The equipment for this market didn't require strict quality specifications. The Pellet Fuels Institute, the trade association that represents pellet manufacturers, industry suppliers, appliance manufacturers and retailers, released a set of standards for the industry in 1995. "They were pretty loose," Wiberg says.

The standards created two classes of pellets-premium and standard. The standards specified ash content, fines and diameter, and had a recommendation for sodium content. The weak points of the standards were a lack of any sort of schedule of testing and acceptable test methods. "It became kind of an optional sort of thing-if you want to use them go ahead," Wiberg says. "The Pellet Fuels Institute put them out there as standards but there was no enforcement."

What happened is that some manufacturers wound up testing their products only once, and assumed their products would continue to match that initial analysis. "So you had people who tested their product one time and it looked like premium [grade] so they sold their pellets as premium from thereon out," Wiberg says.

After a discussion about standards at a Pellet Fuels Institute meeting, Wiberg was approached by a manufacturer who said he would have to start testing his product. "I asked if he had ever tested his product and he hadn't," he continues. "The strange thing about it was that he didn't even know he had to. When he went out for his initial order of bags, the bag supplier printed a guaranteed analysis on the bag, even though there was never an analysis of the material. So it is definitely an industry where some people think a pellet is a pellet is a pellet."

Selling a product as premium grade without an analysis to back it up can open up manufacturers to liability problems. "It's truth in advertising if nothing else," Wiberg says.

A New Standard
Other problems with regulations led the Pellet Fuels Institute to look into revamping its pellet standards. Wiberg says a stove manufacturer was spending more than a quarter of a million dollars per year on repairs under warranty because the fuel used in those stoves was supposedly meeting quality specifications. "Somebody would say come out and repair my defective stove and when they got there they realized it was a fuel problem," Wiberg says. "It said premium on the bag but it wasn't."

In 2005, the institute invited Twin Ports Testing to give a presentation on testing methods. They presented a problem to Wiberg because the Pellet Fuels Institute standards didn't require specific testing methods. "I could tell them how I tested their materials, but not because that's what I was told to do," he adds. "Somebody would say ‘I need moisture number and ash and Btus. Here are my pellets.' If I asked what method they needed to test to, they would have no clue."

While at the institute meeting, Wiberg was invited to sit in on a meeting of the group's standards committee where he heard about the stove manufacturers problems. "I listened to that and I knew what the industry needed to hear," he says. "They needed to understand quality control and quality assurance. I threw out my presentation and told the group they needed to understand quality from the laboratory's point of view."

Wiberg uses the coal industry as an example of the kind of standards the pellet industry needs. "You can't touch coal without using an ASTM procedure," he says. "This industry didn't have that." He also stresses the need for proficiency testing and the need to use traceable standards. He adds that the pellet industry doesn't need specifications as comprehensive as the coal industry, but it does require a true quality control program.

After the 2005 meeting, the group's standards committee created a road map to investigate and promulgate an effective quality control program. The program is more than a set of standards and testing methods. "Standardizing test methods is great, but unless you're going to have some level of enforcement that doesn't mean much," Wiberg says. "The standards also have to mean something. We had to go through every single parameter and ask why we should regulate that parameter."

One standard that got the boot was the sodium standard. Sodium is often used as a proxy for the amount of chloride in a solid fuel, Wiberg says. Too much chloride can cause metal in stoves to corrode. In some fuels this is close enough, but other fuels can have chloride salts of calcium and magnesium so the sodium level will badly underestimate the chloride level. "They thought it was easier to test for sodium than chloride," Wiberg says. "But it's not a very representative test."

There were other tests that were valuable to the pellet industry in Europe that weren't being used in the United States. "One of those was the pellet durability index," Wiberg says.

Hearth and Home
There are differences between the pellet markets in the United States and overseas. In Europe, pellets are used mainly for central heating in furnaces where the American market is primarily stoves and fireplaces. The need for standards that reflected the different markets for pellet fuels became the premise for framing the new standards. "A stove is a lot more finicky," Wiberg says. "It has to have [pellets of] a very consistent density and diameter. So we had to ask, ‘What should a good, high-quality, high-efficiency stove be burning?"

After three years of work, the Pellet Fuels Institute is close to releasing its revised quality standards. The new standards will recognize four grades of pellets: super premium, premium, standard and utility. "Each grade has a specific battery of specifications, both physical and chemical," Wiberg says.

The other part of the specifications is the recognized testing methods for each of the quality parameters. "We did an extensive research project on what methods are out there and who is using what method," Wiberg says. "It wasn't just the European Union. Germany had its own standards as did Austria, Sweden and Britain. There are about a dozen countries that have something going on with pellets. Everybody is kind of doing their own thing."

ASTM International has no standard for fuel pellets, but the Pellet Fuels Institute specifications will follow the ASTM format. If the industry approves the rules, they will be presented to ASTM for consideration as a new standard. Most of the test methods used in the institute's standards are based on recognized ASTM methods.

A few of the methods did have to be modified to cope with the unique property of fuel pellets. Wiberg describes the bulk density test, which in the ASTM standard required a cubic-foot container of pellets to be dropped 6 inches three times. Because pellets are a loose product, dropping a container from 6 inches will cause a significant number of the pellets to fly up and out of the box. So a method using a quarter-cubic-foot box that was tapped from about an inch high was adapted. The group then had to determine how many taps were needed to get a similar result to the ASTM standard. "We probably ran 100 density tests to tell us we were going to tap it 25 times. That seems like a simple thing to recommend, but it probably took us two days to figure out how many times you have to tap pellets."

The other phase of the process for the Pellet Fuels Institute is to provide the tools necessary for pellet manufacturers to start doing quality control in their own plants. "The mill operators are not chemists," Wiberg says. "They don't necessarily know where to buy this equipment and how to run the tests."

Twin Ports Testing went to its suppliers to create a suite of testing equipment that would measure the quality parameters of pellets in an industrial setting. "We needed to find things that nonchemistry-type people can use," Wiberg says. "We also need something that will be representative of the test method used in a lab. It also can't be an overnight deal, because an ongoing [quality assurance/quality control] process control program needs same day results."

The final piece of the quality puzzle is enforcement. The best standards in the world aren't going to do any good if the consumer isn't confident the product meets those standards. So the Pellet Fuels Institute is planning to implement a registration system for manufacturers. Pellet makers would have to show that they have a quality control program and submit quality data quarterly. "The data will show that the company made the grade in the first place and the company continues to comply on an ongoing basis," Wiberg says. "If everything works out right, the company can say its pellets are premium quality and can prove its pellets are premium. Then they get put into the registration system that will be a list of all the mills in the program."

The list of registered manufacturers would be made available to consumers. "Here is a provider with a good quality control program and here is one that isn't," Wiberg says. "Which are you going to buy from?" Stove manufacturers could also require consumers to buy pellets from registered manufacturers or void their warranties.

The first version of the specifications was released in October. The board of the Pellet Fuels Institute made some changes and the standards committee proceeded to convert the standards into ASTM format. The standards then went through a legal review followed by more revisions in February. The current version of the specifications will again be reviewed by the institute's board in late June. Once the board approves the revisions, the standards will go out for an industry vote, likely at the organizations annual meeting in July. "It looks like there is a chance the rules could be adopted as early as this summer," Wiberg says. "Once that happens, then we can start implementing them."

Jerry W. Kram is a Biomass Magazine staff writer. Reach him at or (701) 738-4962.