Brewing Energy

In Australia, converting beer byproducts into energy

By Graeme Stemp-Morlock

On St. Patrick's Day everyone drinks green-colored beer, but in Australia soon everyone will be drinking green beer year round.

That's because Foster's Beer and the University of Queensland announced on Wednesday, May 2 that they would open an experimental wastewater recycling plant that uses a microbial fuel cell at Foster's largest brewery.  The announcement came as the Queensland state government gave the project an additional $140,000 Australian, with Foster's pledging another $30,000 and ground support at the brewery.
"To our knowledge this is the largest project of its kind," said Professor Jurge Keller, Director of the Advanced Wastewater Management Centre (AWMC). "Most other groups are working in labs on a small scale of only a few liters."

The microbial fuel cell will be built at Foster's Yatala brewery, near Brisbane, and it will be able to purify 1000-2000 liters each day.

Foster's is one of Australia's largest breweries, producing 25 percent of all the beer consumed Down Under.

The fuel cell will work in much the same way a chemical fuel cell does but without the expensive hydrogen power source.  Instead, bacteria will eat the leftover starches and sugars from the wastewater and dump their energy on a nearby electrode.  That electrode is connected to a cathode in a different chamber that takes the electrons and combines with air to produce water.

Additionally, the bacteria act as the catalyst in the chemical reactions, making expensive metals like platinum unnecessary.

In addition to producing energy and water, the process will also produce carbon dioxide.  However, Keller believes you could call it "renewable carbon dioxide."

"The CO2 is bound from the atmosphere into grain, which gets harvested and turned into beer.  Some of that makes its way into wastewater and is released, but it's not fossil derived carbon dioxide."

And Foster's is getting twice the energy while releasing a small amount of carbon dioxide, since the company makes energy from the process and saves energy, too.

It's expected that the fuel cell should be able to produce 2kW, so in a day it could produce nearly 50kWh.  Discussions are currently taking place on what to do with that extra energy, said Keller, but it is expected that it will be used on site.

Foster's has been working with the AWMC for many years, and is already the least water-intensive beer in the world.  To produce one liter of Foster's requires only 2.3 liters of water, compared to the average brewing company that uses about 5 liters for every liter of beer. Considering Foster's produces over 400 million liters of beer a year that's a lot of energy savings.

However, Keller believes this kind of fuel cell is ideally suited for smaller breweries, wineries or even soft drink manufacturers because the technology can't be scaled up much more.  Thus, you would need several of these cells to deal with a huge wastewater stream, whereas one cell would be enough for a microbrewery.

Building will begin almost immediately since the goal is to have the fuel cell built in time for a bio-energy conference in September.

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