Conservation
RECYCLING CONSERVES ENERGY
Using recycled materials also greatly reduces the amount of energy needed in manufacturing. In the same study described above, Franklin Associates calculated the energy used to manufacture new products using the newspapers, and metal, glass and plastic containers collected in an average residential curbside recycling program, relative to the energy used to make those products from virgin materials. The study estimates that the reduction in manufacturing energy from using a ton of these recycled materials instead of virgin materials is 18.3 million Btus. This study also estimates that 1.5 million Btus of energy are required to collect the same ton of recyclable materials at the curb, sort them at a processing facility, and transport them to manufacturers. The net reduction in energy use due to recycling is thus estimated at 16.8 million Btus. [15]
Figure
shows this net energy reduction, compared to the net energy yielded by
incinerating municipal solid waste (MSW) and required to landfill MSW. Recycling
was found to produce a net reduction in energy use 3.6 times larger than the
amount of energy generated by incineration of MSW and 11 times larger than the
energy generated by a landfill that recovers methane for energy (a technology
employed at approximately 130 of 4,500 existing landfills).
Most of the reduction in energy needs realized through a curbside recycling program is in the form of electricity used to manufacture virgin aluminum and newsprint. In the case of aluminum, primary smelting and refining processes for the virgin product are displaced by more efficient secondary processes. For newsprint, mechanical grinders that tear wood fibers from logs are replaced by more energy-efficient deinking plants.
Energy has an economic value, which can be measured. Using the average cost of different forms of fuel for industrial facilities, the value of the energy saved per ton of materials collected in a curbside program (accounting also for energy used in collection) is approximately $187 per ton, or roughly five times greater than the landfill disposal fees that recycling avoids.
Using the average value of different fuels to all consumers (industrial, commercial and residential users), the value of the energy saved by curbside recycling is approximately $265 per ton. Over the long term, greater recycling will reduce the need to build more power plants. In this case, the value of the energy saved could be estimated using the marginal cost of adding electrical generating capacity, which would be even higher. In other words, the calculation of a value of $187 per ton for the net energy savings due to curbside recycling is based on a conservative approach.
In incinerators, 45% of garbage either does not burn at all (like bottles and cans) or burns poorly (like wet food waste). Trash is therefore not a good fuel, and the term "waste-to-energy" is something of a misnomer. Unlike a coal-fired power plant, for example, incinerators cover only about one quarter of their total costs through sales of electricity or steam. And on balance, as discussed above, recycling conserves much more energy than is generated by combustion of trash in incinerators.