The Skinny on Fats

The North American rendering industry takes anything that isn't used for food from the animal carcass-all 60 billion pounds-and recycles it into everything from animal feed to biodiesel feedstock. Here's an overview of North American rendering and biodiesel from animal fats.
By Ron Kotrba | October 14, 2008
North American biodiesel production has mainly centered on soybean oil and other virgin vegetable oils, creating somewhat of an unintentional bias in some media coverage. After all, it was state soybean commodity groups who founded the National Biodiesel Board. However, numbers from the Fall 2008 U.S. & Canada Biodiesel Plant Map produced by BBI International and Biodiesel Magazine suggest animal fats still represent a small percentage of straight-feedstocks used for biodiesel production. A steady percentage of animal-fat-derived biodiesel still means a growing volume though, as U.S. projects continue installing production capacity.

Each year, North American renderers turn an average of nearly 60 billion pounds of perishable waste from livestock and poultry processing and supermarket and restaurant operations, into value-added products. In a world without renderers, used restaurant greases and animal carcasses-the bones, blood, viscera, feathers, fats, and any other part of the cow, hog or bird many of us would consider inedible-might be dumped into landfills. Instead, renderers find opportunity in that waste and produce goods ranging from edible tallow or lard to livestock rations such as meat-and-bone meal, blood meal, feather meal and more. The biggest market for rendered goods is the livestock feed market, although many pet foods also contain rendered products. Exports are large too. Last year the United States exported 20 percent of its rendered goods.

Two broad categories of renderers exist today: Captive or packer renderers, who render the inedible materials they produce in their slaughter operations; and independent renderers, who buy fats, used restaurant grease, dead stock and other carcass remains from livestock producers, packing plants, butcher shops and elsewhere. According to Tom Cook, president of the National Renderers Association, captive renderers represent a minority of the rendering business-only 7 percent to 8 percent. The rest are the independent renderers.

Billions of pounds of animal byproduct and waste grease are recycled by North American renderers every year but only a fraction of that material is first-use animal fats and recovered cooking oils. Cook says the amount of total fats and oils production is roughly 13 billion pounds, 2.5 billion to 3 billion pounds of which is recovered cooking oils. Thus the majority of the material is bones, brain matter, spinal chords and all the parts of an animal few want to think about, which bring up issues of disease and infection. Mad cow disease, listeria and avian influenza, to name a few, are always a concern and thus there is a code of practices reputable renderers follow. David Meeker, NRA vice president of scientific services, says most of the advances in rendering over the past few decades have been to increase safety, but other developments implemented simply help make better, and more, products. Meeker says most renderers have upgraded their process from batch to continuous systems over the past 20 years.

"There's been a turnover of equipment from the old batch systems, which had variable outcomes, to computer-controlled continuous cookers," Meeker says. "Now the product is much more consistent. They used to burn a batch every now and then and they don't do that anymore. It's a lot steadier process than it used to be." Meeker says it was also about 20 years ago when the NRA research organization began investigating the potential for making biodiesel from animal fats.

Fat-Derived Biodiesel
Rothsay Rendering is a part of the family of Maple Leaf Foods Inc., and operates as a separate company. MLF owns large hog operations and processing facilities across Canada. Rothsay takes the hog carcasses and remnant materials and makes them into value-added products. "We also participate in the open market to acquire raw materials from other sources," says Todd Moser, Rothsay vice president of alternative fuels. Moser says Rothsay is sort of a hybrid model between the packer and independent renderers. Rothsay operates Rothsay Biodiesel, a 9 MMgy plant on the south shores of Montreal, Quebec, which opened in 2005. While Moser wouldn't give exact numbers, he says only a small portion of Rothsay's available raw materials are used in biodiesel production.

Real or not, there is a perception that biodiesel from animal fats is not as good as soy biodiesel. "There is a bias in the marketplace-we know that," Moser tells Biodiesel Magazine. "But we don't think it's substantiated on the technical merits of the fuel." Rothsay's Web site states that its biodiesel is made from recycled restaurant greases and tallow, but Moser says until there is tax parity in the U.S. federal blenders credit for waste vegetable oil and "first-use" animal fats, the plant will continue to produce a majority of its biodiesel from the more expensive tallow. As of late September, waste vegetable oil was only eligible for a half-penny per percentage point blended into petroleum diesel whereas tallow receives the full penny. "We definitely have the capacity, capability and willingness to use more [waste vegetable oil] but what's preventing that now is the tax disparity in the U.S.," he says. Congress was expected to vote on the revised version of the blenders credit, Sept. 23. Tyson officials told CNN that, if the revised blenders credit passes excluding biomass-based feedstocks (animal fats) when coprocessed with petroleum, its plans with ConocoPhilips to produce a renewable diesel would fold. Tyson didn't respond to requests to participate in this article. Other NRA members including Griffin Industries, Smithfield Foods and Sanimax also didn't respond to requests from Biodiesel Magazine to comment for this article.

Cold Flow Chart

If restaurant grease is given tax parity in the extension, Moser says Rothsay would make a big feedstock switch. "Recycled restaurant grease is less expensive and we believe it has greater environmental benefits long term if you're looking at a total life-cycle approach," he says.

Moser says the most easily scrutinized characteristic of tallow-based biodiesel is its high cloud point compared with soy or canola biodiesel. "There are advantages of animal-fat-based biodiesel that aren't getting any sort of equity and, of course, the easy one to knock is cold-flow properties, which we don't necessarily dispute in B100," he says. According to National Renewable Energy Laboratory, the cloud point of biodiesel from inedible tallow is 61 degrees Fahrenheit. The cloud point for soy biodiesel is 38 degrees F and canola's cloud point is as low as 26 degrees. Moser says, "We would like consumers to have a better understanding of what the implications of those technical differences really are in the low-level blends that are being used."

Animal-fat-derived biodiesel is often criticized for high cloud point, but what is less reported is that it has a higher cetane number, which means better ignition properties and reduced nitrous oxide emissions. Also, tallow biodiesel is comprised of saturated fatty acids making it inherently more stable. There is no cold-flow spec in ASTM, and Meeker says if the fuel meets specs, there should be little or no issue-especially in a B5 blend.

To ensure quality and consistency from their animal-fat derived biodiesel, a distillation system was added to the Rothsay plant last year as "a second line of defense," Moser says. "It has resulted in an even purer biodiesel and it sets the industry quality standard for animal-fat-based biodiesel, for sure. It's a water-white product coming off our distillation unit-very high quality. It was well worth the investment for that added peace of mind."

Markets: A Rising Tide Lifts All Ships
In 2007, the U.S. Census Bureau began tracking the use of animal fats and greases in biodiesel production. According to the bureau, 173.1 million pounds of animal fats and greases were used in 2007 for U.S. biodiesel production-about 4 percent of the total feedstock required to make the 500-plus million gallons produced last year. While animal fats and greases made up 4 percent of U.S. biodiesel feedstocks, when looked at conversely, the U.S. biodiesel industry consumed approximately 2 percent of total U.S. production of fats and greases last year.

Meeker says earlier this year the NRA predicted between 3 percent and 8 percent of all rendered animal fats and greases might be going to biodiesel. "I realize that's a wide window, but in reading other data it's probably closer to 8 percent," he says. "Fats in the 40- to 50-cent-a-pound range, you think, 'Wow, that's pretty high priced,' but it's still a good deal making biodiesel when crude oil is at $140 a barrel. And if corn's $7 a bushel, 40-cent fat looks pretty good in chicken feed, so there are so many competing economic forces at play it's hard to predict how big of a market [biodiesel can be for rendered fats and greases]." Compared with the record-high vegetable oil prices seen recently, it's no wonder biodiesel producers might desire animal fats as feedstock. But, "the saying 'A Rising Tide Lifts All Ships' is true for our industry," Cook says.

There are all kinds of influences on animal fat markets and pricing. "It's a complicated relationship," Meeker says. "As far as using fats for biodiesel goes, it's impacted by the price of crude oil so when that's up the substitutes are up-including our rendered products-but our biggest use is still animal feed, so we're also impacted by the use of corn, soybeans and so on. We're trying to pull two directions and recently everything has been up."

All of these markets are volatile. On Sept. 22, the United States saw the biggest one-day jump, $16 a barrel, in crude prices. Crop and livestock markets are volatile too. "If more cattle come to market there'll be a down tick in tallow, and a different environmental law in Indonesia might mean a big uptick in palm," Meeker says. The high cost of grain and soybeans this year may translate into less available animal fats next year. High feed prices could force livestock producers to cut back on the number of cattle or pigs they are going to feed. "That makes a little less raw material for us to render," Meeker explains. Then there are trends that move more animal fats into the marketplace. "Trends like more centralized meat cutting and case-ready consumer products make it more likely those trim fats and waste products will end up at rendering facilities rather than a landfill," he says. "So despite a short-term drop in animal production because of feed prices, overall there'll be growth in these rendered fats being available."

Ron Kotrba is a Biodiesel Magazine senior writer. Reach him at or (701) 738-4942.
Array ( [REDIRECT_REDIRECT_STATUS] => 200 [REDIRECT_STATUS] => 200 [HTTP_USER_AGENT] => CCBot/2.0 ( [HTTP_ACCEPT] => text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 [HTTP_ACCEPT_LANGUAGE] => en-US,en;q=0.5 [HTTP_IF_MODIFIED_SINCE] => Mon, 26 Aug 2019 03:35:59 UTC [HTTP_ACCEPT_ENCODING] => br,gzip [HTTP_HOST] => [HTTP_CONNECTION] => Keep-Alive [PATH] => /sbin:/usr/sbin:/bin:/usr/bin [SERVER_SIGNATURE] =>
Apache/2.2.15 (CentOS) Server at Port 80
[SERVER_SOFTWARE] => Apache/2.2.15 (CentOS) [SERVER_NAME] => [SERVER_ADDR] => [SERVER_PORT] => 80 [REMOTE_ADDR] => [DOCUMENT_ROOT] => /datadrive/websites/ [SERVER_ADMIN] => [SCRIPT_FILENAME] => /datadrive/websites/ [REMOTE_PORT] => 55390 [REDIRECT_QUERY_STRING] => url=articles/2879/the-skinny-on-fats [REDIRECT_URL] => /app/webroot/articles/2879/the-skinny-on-fats [GATEWAY_INTERFACE] => CGI/1.1 [SERVER_PROTOCOL] => HTTP/1.1 [REQUEST_METHOD] => GET [QUERY_STRING] => url=articles/2879/the-skinny-on-fats [REQUEST_URI] => /articles/2879/the-skinny-on-fats [SCRIPT_NAME] => /app/webroot/index.php [PHP_SELF] => /app/webroot/index.php [REQUEST_TIME_FLOAT] => 1580287984.814 [REQUEST_TIME] => 1580287984 )