Turning Rubbish Into Biogas In Sweden  

TreeHugger has a post on the expanding use of biogas in Sweden - From Kitchen Scraps to Biogas - Stockholm Embraces Garbage Disposals.

Previously, a high annual fee discouraged apartment dwellers from thinking about owning a garbage disposal - municipal engineers were worried about gas build-up in sewer lines and other blockages from running liquid garbage through regular pipes. So only about 40 apartments in the entire city went through the expensive hassle of getting and owning a garbage disposal. In the U.S. 50 percent of ALL homes have a disposal - it increases a home's water consumption and electricity usage and forms more of a burden to municipal sewage treatment. Why are the Swedes encouraging it, then? They want to mine the waste stream for biogas.

An increase in organic material in Swedish sewage lines is now considered a positive, so the fee for the garbage disposals reduced by more than half to U.S.$65 dollars - purchase and installation of a machine will still cost around $800.

In Sweden there's a national goal of 35 percent of waste material being composted or by 2010. That may be a tough goal to reach as many people toss everything into the trash, knowing that most of it gets burned in large incinerators Sweden invested in in the 70's and 80's. One study showed Swedes tossing 225 pounds of edible food each year.

By using garbage disposals, Stockholm Water reckons they can turn that waste into methane gas. Scores of methane stations dot the Swedish roadsides and methane is used in many city buses - though Volvo discontinued its dual methane/gas powered car two years ago. Stockholm Water has now tested the pipes, so to speak, and determined that the system can absorb a lot more of the waste stream in the municipal system and turn it into methane gas, so that an even larger goal recommended by the Green party could be reached. The Greens say 70 percent of the waste stream could be either composted or turned to biogas by 2015. Today Stockholm Water can produce 8 billion cubic meters of methane, though just half of it goes to vehicles.

Last year demand for methane rose 18 percent, but in Stockholm it rose a full 40 percent. Stockholm can't make enough of its own biogas currently, and imports from nearby municipalities. Sweden's Environmental Protection Agency lists biogas as the most environmentally friendly vehicle fuel - there's even the biogas-powered train.