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Ethanol from trashy sources advances

Firms turn to garbage and wheat straw to make the fuel alcohol

by Melody M. Bomgardner
September 25, 2017 | A version of this story appeared in Volume 95, Issue 38

A photo of Enerkem's plant in Edmonton, Alberta, which makes ethanol from municipal solid waste.
Credit: Enerkem
Enerkem's plant in Edmonton, Alberta, makes ethanol from municipal solid waste.

Residents of Edmonton, Alberta, will soon be able to fuel their cars with household garbage, albeit indirectly. Enerkem says it is successfully producing ethanol from nonrecyclable or noncompostable trash at a nearby facility it first turned on back in 2014.

At Enerkem’s plant, trash is gasified and then converted to methanol using catalysts. A separate on-site process transforms the methanol to ethanol. The company plans to progressively increase ethanol production in Edmonton while it pursues similar projects in Europe and China.

Almost all gasoline blends in North America contain ethanol made from corn; the cost of the fuel generally tracks with corn prices. In contrast, biofuels made from waste could end up being cheaper since municipalities have to pay to landfill or incinerate household trash.

But building big gasification plants that use new technology or unusual feedstocks is expensive and risky. Earlier attempts by biofuels firms KiOR and Range Fuels to gasify waste led to bankruptcies. Enerkem developed a bubbling, fluidized bed gasifier that runs at lower temperature and pressure than traditional plasma gasifiers.

Ethanol from garbage is classified as cellulosic ethanol by regulators, making it similar to biofuels made from agricultural wastes. These advanced biofuels offer higher greenhouse gas savings than does ethanol made from crops, and they don’t displace land used to grow food.

In Europe, where bioethanol is made mainly from wheat, regulators have instituted mandates requiring new facilities to produce biofuels with a minimum of 60% greenhouse gas savings over fossil fuels. That could put wheat-growing regions of Eastern Europe at a disadvantage.

Now, the Slovakian company Enviral plans to make cellulosic ethanol from wheat straw at its Leopoldov site using Sunliquid technology licensed from the chemical maker Clariant. The process uses specialized enzymes to break down the tough straw along with microbes that can ferment a mixture of C5 and C6 sugars into ethanol.

The firms plan to break ground by the end of the year. “It marks our official entrance into the market and the successful commercialization of this highly innovative and sustainable technology,” says Christian Kohlpaintner, a member of Clariant’s executive committee.



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