Coca-Cola Central Japan has installed something called the "eKOsystem," a methane fermentation system which uses the coffee grounds and tea leaves left over from the manufacturing of coffee and tea-based drinks to provide heat and energy for the plant.
Relying on a waste to energy scheme should lower the company's operating costs by reducing waste volumes and associated waste transport/processing costs, enable energy savings by use of generated methane gas in the plant, and reduce the environmental effects of CO2 that would normally get released into the atmosphere as the coffee and tealeaf waste ferments.
The system costs $3.9 million (JPY 420 million), and the installation was part of a joint research project with the New Energy and Industrial Technology Development Organization, a government agency.
Similar to agricultural methane digesters it seems. I wonder if the material being digested might not have more value as compost? Interesting effort nonetheless! I'm actually surprised that it can be done, given the acids, tannins, etc. that are part of coffee and tea...
"...reduce the environmental effects of CO2 that would normally get released into the atmosphere as the coffee and tealeaf waste ferments."
??? Surely burning the waste will release the CO2 as well, and at a much faster rate?
I think the point's that as greenhouse gases go, methane's a much more potent/damaging/dangerous gas than CO2.
Thus, while the plant does generate CO2, you still win because you're not releasing methane.
Regarding burning, you're not burning the grounds & leaves. You let them decay in a big bin and collect the methane that they generate as they ferment. Then you burn the _gas_. I think you can still use the fermented grounds & leaves as fertiliser afterwards.
Ah, I _knew_ there was a nice factor out there!
says that "methane is a greenhouse gas with a global warming potential of 21 (meaning that it has 21 times the warming ability of carbon dioxide)."