Embodied Energy: We Can't Measure the Impact of Solid Waste Unless We Study the Energy We Throw Away
Morawski, Clarissa, Alternatives Journal
WASTE discussions have traditionally focused on the back-end management of garbage: the significant economic and environmental implications of finding safe disposal sites, for example. But the obvious often escapes us--that garbage is made up of basic materials (metal, wood, plastic, glass, etc.) that require energy to obtain, process and manufacture.
When we throw something away, we also throw away the embodied energy used to make it. Huge amounts of energy are used to extract the primary resources required for virgin materials from which new products are made. More again goes into manufacturing. Rarely is this lost energy considered.
New products made from recycled materials require much less energy because primary resource extraction is avoided. If a new product is reused, then even more energy is saved because manufacturing is avoided. And if we avoid using something altogether, the greatest amount of energy is saved. Here are a few examples.
Using recycled aluminum cans to make new cans means avoiding limestone, salt and bauxite mining; it also eliminates the need for caustic soda, chlorine, alumina, crude oil, petroleum coke, and anode production. Using recycled cans rather than virgin aluminum as feedstock for the production of sheet metal requires 95 percent less energy.
Manufacturing corrugated packaging with old corrugate requires no round-wood harvesting, wood residual production, sodium and sulfate mining, soda ash production, or cornstarch manufacture.
Using recycled glass to make new bottles avoids limestone, glass sand, soda ash and feldspar mining.
Reusing glass bottles eliminates the need for post-consumer cullet recovery and processing, and the additional manufacturing of glass containers.
Re-refining used oil into new lubricating oil avoids crude oil exploration, drilling, water injection, heavy crude and bitumen extraction, and transportation via pipeline or shipping to the refinery.
Avoiding all these up-stream functions means significantly reducing energy use and associated greenhouse gas emissions.
Thanks to extensive lifecycle-analysis studies recently undertaken by both the US Environmental Protection Agency and Environment Canada, we can identify actual energy savings from reduction, reuse and recycling efforts. The data reveal important insights into the impact of waste diversion programs on energy conservation. …