Compost

Finished compost looks and smells like dark, crumbly soil. It can be screened to remove chunks that have not fully decomposed. Julie Riley photo

Generally, when we think of where our daily consumptive energy comes from we usually think along the lines of extraction and conversion from raw, natural resources. With transportation needs, often drilling rigs pulling up oil and gas with subsequent refinery work come to mind. With heating water, many picture solar panels and conversion to 110 volt or 220 volt line electricity — or even heat exchangers in fluid tanks. Many community electrical powerhouses in Western Alaska have looked to wind currents spinning turbine generators for electrical grid distribution, or to dams that can collect a sufficient head of river or creek water to generate much of the utility scale electricity in Southeast Alaska.

But there are sources of “reuse” that can supply needed energy, whether for heat or electrical generation. That is, directing aftermarket waste to energy uses is a possibility many are looking into. The simplest example you probably have seen if you know someone who uses a woodstove is using cardboard boxes that have been used for transporting goods as fire starter and to supplement cord wood combusted for space heat. Those boxes that end up going to the landfill are biodegradable, and many landfills now recover the methane gas after decomposing wood products such as cardboard falls apart under the surface. The methane then can often run turbines for the landfill’s own energy consumption during its operations. Waste yard clippings, food items and forest litter are at times piled up in containers near greenhouse operations and the generated heat from that compost decaying is used by some as a direct heat source in food growing operations.

I was reminded at the Chena Hot Springs Energy Fair on Aug. 15 that there had been past demonstrations onsite about recovering even potential liquid fuels from spent plastic containers through the use of certain presses. This is a bit more complex method of “waste to energy” conversion as it requires up-front sorting, sequestering certain types of plastics and the use of machinery in the process. But it is a workable way of removing non-biodegradable plastics from solid wastes. That waste liquid can be used to provide thermal heat or transportation. I was in a mechanic’s shop in North Pole a few years ago and observed an off-the-shelf stove that could directly burn spent motor oil for heating his place of business. An Interior Alaska large equipment operator was supplementing his fuel pump diesel for his excavators by directly mixing it with spent vegetable oil (being disposed of by a major food service company’s cafeteria).

While increasing the efficiency of running motors and energy producing generators is smart to further the “bang for the buck” when collecting and converting raw resources into useable energy, there is a two-fold advantage to converting waste to energy. First off, the direct energy content of the disposed waste is generally easy to convert when comparing it to the initial intensive activities of extraction, refining and distributing natural resource-derived energy. But just as important, this type of reuse at the residential or community level helps to reduce the burden on the waste stream. That is, less effort and energy are used for garbage collection and disposal due to those displaced items being absent, and there is less space taken up in landfills. This in turn reduces the tying up of more land development for expanding junkyards. Think of what you throw away at your home level and investigate how those items may be used as an energy source for heat, transportation or even power.

Art Nash is the Extension energy and radon specialist for the University of Alaska Fairbanks Cooperative Extension Service. Contact him at 907-474-6366 or by email at alnashjr@alaska.edu.

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