MU students, faculty give coffee grounds a new purpose

Tuesday, April 20, 2010 | 12:01 a.m. CDT; updated 10:44 a.m. CDT, Wednesday, April 21, 2010
Postdoctoral researcher Mudahar Abdullah displays test tubes of biofuels that are extracted from coffee grounds at MU's Agricultural Engineering Building. MU is perfecting the extraction process to make it efficient and more practical.

*CORRECTION: Bulent Koc is an assistant professor of agricultural systems management. An earlier version of this story incorrectly identified him.

COLUMBIA — That cup of coffee that gets you going every morning may one day get your car going.

Researchers from MU’s Agriculture Systems Management Biofuels Lab have succeeded in converting leftover coffee grounds into biodiesel fuel.


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The grounds may offer another “kitchen alternative” to diesel fuel, along with soybeans and animal fat.

“There is a large focus on finding other alternatives,” said MU Professor Leon Schumacher, who is with the agriculture systems management department.

“Even if we had soy beans planted all over the world, and even if we took all of the fat from all of the slaughterhouses, we still wouldn’t be able to replace all the diesel.”

Research on coffee grounds began at the University of Nevada a few years ago, but MU is the only university continuing the research now, said Bulent Koc*, assistant professor in agriculture systems management.

The research began last semester when two visiting students from Germany took an interest in the project. Working with Koc, they began to collect leftover coffee grounds from the Agriculture Engineering Building.

“The hardest part was collecting enough coffee grounds to get a substantial amount of oil,” Koc said. “Ten grams of coffee would yield 1.3 grams of oil.”

After the researchers had collected a sufficient amount, they began the process of converting it into fuel that could be used in a gas tank.

First, the grounds are dried in an oven to release the moisture, then submitted to  a standard oil extraction process, followed by a process called transesterification, which uses an alcohol to convert the dry base into biodiesel.

The result? Java-scented fuel.

This semester, Mudahar Abdullah, a graduate student at MU, is continuing the research, trying to eliminate the drying step in the process. This would save time and energy, Koc said.

Typically, to create energy, another form of energy must be consumed. It becomes a question of trade-offs, Schumacher said.

“We have to look at how much energy we are losing in comparison to how much we are gaining and weigh it,” Koc said.

Researchers must also compare the usefulness of coffee grounds to the other kitchen alternatives, such as soy beans.

Coffee grounds contain 13 percent oil, while soy beans can contain anywhere from 18-22 percent oil, Schumacher said. Using coffee grounds, however, has certain benefits.

“The biggest advantage to using coffee grounds is that otherwise they would be thrown away,” Schumacher said. “Throwing them in a landfill would be throwing potential oil away.”

Growers produce more than 16 billion pounds of coffee each year, according to the National Coffee Association. Coffee will be grown whether it's used for fuel or not; the leftovers might as well be used for a purpose, Schumacher said.

Other alternatives, like soy beans, are resources grown intentionally for fuel. This not only affects the biodiversity of the land where they are being harvested, it also takes a potential food source away from impoverished countries.

The "food for fuel" argument is based on this principle: Where hunger and poverty are widespread, food should be used for food, not to power cars in wealthier countries — especially not at the cost of rising food prices, according to Food and Fuel

This would not be an issue with coffee grounds, a surplus resource.

Starbucks alone generates 210 million pounds of spent coffee grounds each year in the United States.

"You shouldn't be throwing away plastic, cans or glass," Schumacher said. "Coffee grounds are the same."

There is more to creating an alternative fuel source than just the technology of the conversion, however. The costs, supply and delivery have to be taken into account as well, said Seth Meyer, an analyst for the Food and Agricultural Policy Research Institute.

"Science leads the way with these extractions and then economics steps in," Meyer said.

It is probably too early to tell whether this will become a widespread alternative, he said.

Even if the 210 million pounds of Starbucks coffee grounds were collected in one year, it would amount to about 2.92 million gallons of biodiesel, according to

The United States produced 650 million gallons of biodiesel in 2008, according to Biodiesel 2020, a publication that tracks U.S. and global markets for biodiesel growth.

"It may not be economically viable to go around collecting the grounds from the Starbucks here in Columbia," Meyer said. "But maybe it would be in New York, who knows?"

"It is not a matter of whether it can be done, but should it be done."

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Mark Foecking April 20, 2010 | 9:07 a.m.

This is a well written article that does a good job examining the tradeoffs and problems in replacsing our use of petroleum with biofuels.

Using information in the article, I calculate that if all 16 billion pounds of coffee grounds grown per year were used to make biodiesel, it would replace less that 0.1% of our current oil usage. The problem is not whether it can or should be done, the problem is we use so much oil. Advocating biofuels *must* mean you advocate radical conservation and efficiency measures. To tell people otherwise is tragically misleading.


(Report Comment)
Ellis Smith April 20, 2010 | 10:02 a.m.

A parallel situation exists with "fuel" for production of electrical energy. Wind and solar power generation should be developed and applied where it is practical to do so, but we presently derive more than 70% of our electrical energy (it's closer to 80%) from combustion of fossil fuels (mostly coal). France derives more than 70% of its electricity from nuclear reactors, which do not emit carbon dioxide.

Experts who have done their calculations agree that we cannot produce the electrical energy we presently consume by using only wind and solar generation, let alone meet future demand.

(Report Comment)
Mark Foecking April 20, 2010 | 4:01 p.m.

I wouldn't say "cannot", because with enough time and effort (and it's a LOT of both) it would be possible to convert from fossil energy to solar and wind. We'll have to someday, as fossil fuels have their limits, as well as possibly quite serious environmental consequences. For these reasons I think that we need to build another generation of nukes as well as installing as much wind and solar as possible.

The world is currently installing about 10 GW of solar and about 40 GW of wind (which only generate as much energy as fossil plants 1/4 the size) every year. This represents an investment of about 120 billion dollars/year. That's actually very expensive compared to any other form of conventional energy including nuclear. It's because wind and solar only generate about 1/5-1/3 of their rated capacity on the average (depending on location). Everything else does in the 80-90% range.

We need to install roughly three terawatts (3000 GW) of wind and solar, just in the US, to replace current fossil fuel generation. At current rates (we install about 1/3 of world solar and wind every year), that will happen in about 180 years.

Some methods of energy storage, and the ability to route large amounts of power where needed quickly, are also necessary to preserve grid reliability. Both approaches have complex, largely unsolved problems, and neither have any appreciable operating history.

Like I say, we'll need renewable sources of power in the future to get away from limited fossil sources. But to present renewables as a readily available, proven solution to our energy needs (as many environmental leaders and groups do) is to grossly mislead.


(Report Comment)
Ellis Smith April 21, 2010 | 4:39 a.m.

@ Mark Foecking

Seems to me we have no disagreement. In a society whose collective patience can sometimes be measured in mere nanoseconds, 180 years is a very long time.

The energy fiasco is not without its humorous aspects. Take this multi-campus university for example. At one campus people are demonstrating (carrying little signs) and writing letters to end the use of coal to create campus energy; concurrently at another campus of the same university work is under way, paid for by the Department of Energy (our tax dollars at work!), to improve the coal gasification process. BTW, the third partner in that experimentation, besides DOE and MS&T, is Ameren UE. Now there's an unholy trinity if there ever was one!

These situations are not diametrically opposed, but they do illustrate the fact that the missions of the two campuses aren't the same and have never been the same for 140 years, which isn't 180 years - but close!

(Report Comment)

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