Corporate sustainability needs renewable energy from waste

Departments - Critical Thinking

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April 8, 2015
Harvey Gershman

If your waste could be used on-site to heat or power your own plant, like lumber mills for example, wouldn’t it seem logical to count that as diversion?

The table to the right presents some large companies with zero-waste-to-landfill (ZWL) facilities. Although some acknowledge the inclusion of renewable energy from waste in their ZWL efforts, several do not, as it seems not all certifiers count WTE as diversion.

The importance of using the leftover fuel and energy value after reduce/reuse/recycle activities is very critical to achieve ZWL. There is, however, a limit to the capacity that is currently in place in the U.S. for this. Approximately 10 percent of U.S. waste currently goes to WTE. Most of this capacity is mass-burn, while only a small percentage is used as a supplemental fuel in existing coal-fired utility boilers or into cement kilns—a common application for municipal solid waste (MSW)-derived fuels in European Union countries that boast ZWL.

In the U.S., we still have significant power-generating capacity and cement production based on coal. In 2012, there were 572 operational power plants consuming 825 million tons of coal and 107 cement kilns consuming some 360 trillion British thermal units (Btu) of various fuels to make cement. In cement-making, any residue in the fuel becomes part of the clinker product. Therefore, the quality of the fuel is important to keep the cement chemistry within standards. And, many cement manufacturers have figured out how to do this with many different kinds of waste-derived fuels.

CalRecycle validated the use of a refuse-derived fuel as an alternative/supplemental fuel for cement kilns in 2014, following requests from industry during facility siting efforts and state review of materials definitions. We could make a giant step toward achieving true ZWL if we could displace 10 percent of the nonrenewable fuel used in these coal-fired power plants and cement manufacturing plants with approximately 136 million tons per year of MSW refuse-derived fuel (RDF) or engineered fuel (assuming 6,000 Btu per pound heat value.)
 

Sources of fuel could include residues from dirty material recovery facilities (MRFs) and mixed waste processing facilities; residuals from “one-bin” systems; and, the “black bin” in systems that are source-separating or processing three streams: recyclables, organics and other. This fuel could also be used in dedicated boilers with small heating/cooling loads in university settings or tied to existing or new industries needing steam supply 24/7, preferably always set up in cogeneration modes.

RDF use in power plants reduces the emission levels of sulfur dioxide and would decrease greenhouse gas (GHG) production in landfills.

ZWL that includes renewable energy from waste are good for manufacturing and corporations. Next month we will explore how to increase its acceptability and use by local governments and regional solid waste authorities.

 


Harvey Gershman is president of Gershman, Brickner & Bratton Inc., solid waste management consultants, hgershman@gbbinc.com. Research assistance provided by Brad Kelley, GBB senior project engineer and Ljupka Arsova, GBB consultant II. Sustainability perspective from Kate Vasquez, GBB senior consultant.