A Minneapolis startup company is working on a process to create a form of coal out of biomass that would emit less pollution and serve as a renewable source of energy.
Torrefaction Systems Inc. (or Torrsys), a spinoff of Bepex International LLC, has been at work for more than 18 months on what it calls “biocoal,” a new energy source that chemically converts biomass feedstocks like corn stalks into coal - but without as many negative combustion byproducts such as nitrate oxides, mercury and sulfur.
The company built a small pilot torrefaction plant in north Minneapolis that operates about 500 hours a year on an experimental basis, says Kevin Grotheim, a mechanical engineer and the 34-year-old president of Torrsys. The resulting biocoal produced by the plant has been successfully tested at District Energy’s biomass burner in St. Paul and at a facility at North Dakota State University.
Testing and selling biocoal to the utility markets are two different things, of course. Commercializing the product remains challenging, especially in a climate of risk-averse investors who lack patience for the two or three years more of development that Torrsys requires.
“Our runway is too long of a time span for today’s investment environment,” says Grotheim
Plus, “the biocoal process is quite complex,” says Dale Roberts, Bepex’s chairman of the board. “No one in the world has been able to do a commercial plant but many have tried - and failed.”
The inability of the U.S. Congress to create consistent and reliable energy legislation, especially on the pricing of carbon, has not helped. “The lack of a national policy … is hindering our natural, technical competitive advantage in emerging clean tech,” Grotheim says. “Indecision is a worse enemy than a ‘for’ or a ‘yea’ decision” on climate policy.
Bepex managed to win a nearly $1 million grant from the Xcel Energy Renewable Development Fund in 2008 that helped start the testing of biomass and the construction of the biocoal plant in northeast Minneapolis. The plant has produced and tested 25 tons of biocoal, which Grotheim claims is a quantity reached by only a handful of companies globally.
Torrsys is not alone in seeing biomass torrefaction as having an important role in a greener energy future. Vancouver, B.C.’s Bio-Coal Energy Inc. announced in June it would open the “world’s first biocoal” plant next year capable of producing 25 tons an hour. The company also thinks British Columbia could support as many as 30 plants.
At least two nationally known scientists who have studied Torrsys’ approach find it commercially viable if certain roadblocks can be overcome. Adel Sarofim, a professor at the University of Idaho, wrote in an e-mail that biomass subjected to torrefaction, a heating and drying process, could be mixed with typical coal for use at energy plants. He sees it as a viable addition to the supply chain of coal-fired plants.
Richard Boardman, who works at the Idaho National Laboratory, wrote in an e-mail that torrefaction “will likely have commercial value to producing a uniform commodity that is similar to coal” but suggests more development is still needed.
Facing carbon-reduction mandates and dwindling coal stockpiles, a handful of Asian and European companies have expressed interest in collaborating and perhaps sponsoring Torrsys’ research, Grotheim says. Other companies who may become strategic partners include those in forestry, commodity trading, energy and coal-fired utilities.
For the time being, financing continues to come from the Xcel grant and from Bepex, a 50-person process development and equipment company which spun Torrsys off to capture outside investment and avoid diminishing its core business, says Grotheim. Bepex executives think if Torrsys succeeds, the revenue it produces could “dwarf” other operations.
Best known for selling the technology behind the creation of charcoal briquettes, Bepex has other products in development with a sustainable flavor, Roberts says. One is a process that recycles plastic bottles to a standard that’s clean enough for reuse as food containers and bottles, an application Roberts hopes the recycling industry embraces.
Whether biocoal will find supporters remains an issue, too. Coal is an ogre in the clean tech world, and many companies are working to replace it with natural gas, wind, solar, geothermal or wave energy, to name a few competitors.
For the foreseeable future, coal will remain part of the energy landscape because of its vast supplies and an entire infrastructure devoted to it. More than 50 percent of the world’s electric energy production derives from coal, a figure unlikely to drop anytime soon, Roberts says.
Biomass converted to biocoal can be transported and burned in the same way as regular coal, says Grotheim. The primary advantage of biocoal is it is considered “carbon neutral.” As biomass, it sequesters carbon. As biocoal, it releases roughly the same amount of carbon dioxide as it sequestered.
Another advantage is that biocoal “greens” the coal industry without any new infrastructure having to be built, Grotheim says.
A Minnesota Office of Energy Security report released last year cited torrefied biomass as a potential new source of clean energy.
“Co-firing biomass with coal has proven to be a near-term method to reduce CO2 emissions per kilowatt hour, and has helped utilities meet renewable energy portfolio standards,” the OES wrote in Clean Energy Technology Roadmap. “Research that determines cost-effective biomass pre-treatment options for existing coal-fired plants to continue production of electricity while meeting renewable energy and CO2 emissions reduction targets will develop long-term, stable markets for biomass.”
Another important benefit, according to Grotheim, is the reduction in mercury, sulfur and nitrate oxides, all present in higher concentrations in coal. By any measure, the coal industry’s practices - from mountaintop removal in West Virginia to dangerous underground mining in the news - could be lessened with the introduction of biocoal, its proponents say.
So how does Torrsys create biocoal? Biomass is dried, heated to about 540 degrees Fahrenheit and then subjected to immense pressure in an oxygen-free environment. Think of it as coal production on steroids, reducing the 100 million years nature requires to produce coal from virgin biomass to about 15 minutes. The resulting biocoal is the equivalent of some sub-bituminous or lignite coals.
Much of the process itself is nothing new. Grotheim points out that elements of the torrefaction process have been around 50 years and in use at dozens of Fortune 500 corporations. What is innovative, however, is the torrefaction and “densification” of biomass, he says.
Torrsys has mixed and matched biomass ingredients at its test plant, among them forest materials, corn stover and sugar cane waste. Others will be tested over the next six months. It turns out that plant materials related to sugar and ethanol production make for fine biocoal, he says.
The next steps for Torrsys involve continued testing of different feedstock biomass, and in various combinations, to determine which formulas will have the highest energy value. If the company can find the appropriate financial partner it would like to build a 24-ton demonstration plant in the future.
That would be enough to create a product Torrsys could sell and, more important, prove that its process can scale upward, Grotheim says. He has standing offers from utilities willing to buy 500 tons of biocoal - the amount used in an average day at Minnesota’s larger coal-fired plants - but he does not have the financial resources to reach that quantity.
Biocoal could never replace coal and so far, nothing can. For Torrsys the question will be whether it can attract enough investors to allow it to make the final leap from pilot project to commercial entity. In a “Disney World ending,” Grotheim says, “it could be one of many approaches as the world searches for new sources and new ways to fulfill our energy needs.”