After 3R’s, recover energy from waste or landfill?
Context: Low and middle income countries generate less waste per person and recycle comparably with high income countries. But, the burgeoning amount of waste after recycling ends up in open dumpsites, jeopardizing public health, degrading quality of life and polluting the environment. In such situations, it is not easy to answer the question “energy from waste or landfill?”. In this context, we hope this article contributes to informed decision making. ~ be Waste Wise
Perinaz Bhada-Tata (Solid Waste and Climate Change Consultant).
This article originally appeared in Handshake, International Finance Corporation’s quarterly journal on public-private partnerships, January 2014.
It is published here as part of the 2014 Global Dialogue on Waste under the Public Health & Quality of Life theme.
There is no ideal way to dispose of waste. All options are expensive and have myriad impacts, so waste managers need to select from among several challenging choices. Better decisions are made when the public is part of the decision making process and supports an ongoing waste management program.
The most hotly debated topic in many waste management discussions is whether to burn or bury our waste. This discussion centers around the world’s two most popular waste disposal options: energy from waste (EFW), which is also known as waste to energy, and landfilling. But rarely is there an “either/or” scenario; landfill and energy from waste must co-exist as they fulfill different roles in an integrated waste management program. Here we discuss the merits of each model from the perspective of technology, cost, local considerations, and global environmental impact.
Yesterday’s highly polluting trash incinerators and dumpsites burden both energy from waste and sanitary landfilling efforts. Air pollution control technology employed in today’s energy from waste facilities is so highly advanced that dangerous pollutants, such as dioxins (?) and heavy metals, have been virtually eliminated—in some cases by as much as 99 percent. Germany’s Ministry of the Environment reports, for example, that residential fireplaces emit 20 times more dioxins than energy from waste plants. Many plants also enable real-time monitoring of key operational parameters, such as carbon monoxide levels and temperature of stack emissions, providing important assurances to nearby residents and regulatory authorities. Such plants benefit from regular and sustained technological advances. Landfilling, although not as dependent on technology as energy from waste, also benefits from regular process improvements. Procedures to recirculate leachate (?), improve leachate treatment, and update collection of landfill gas are constantly reevaluated.
Total costs for energy from waste are about $70 to $200 per tonne, while sanitary landfilling is less than half that at $40 to $100 per tonne (What A Waste: A Global Review of Solid Waste Management). However, these costs are often difficult to compare directly as ancillary benefits and local subsidies affect total costs.
The method of procurement is slightly different for energy from waste facilities and landfills. An energy from waste plant is similar to purchasing a costly building that is operated over its lifespan. A landfill, on the other hand, is similar to an ongoing civil works project. The finished product is a green space such as a golf course or park. Financing an energy from waste plant requires upfront capital, usually issued through bonds or the operator’s own financing. Comparing costs of landfilling and energy from waste is challenging since they are considerably different. The total cost is impacted by considerations that are often set by political dictate, like feed-in tariffs for generated electricity, a price on carbon, and location and cost of land. Other important cost inputs include prices of recyclables, ash disposal costs, environmental legislation (stack emissions and leachate treatment standards), and tipping fees.
Few other issues have the potential to generate street protests from residents than announcing a planned landfill or other waste disposal facility in their neighborhood. The fury is often exacerbated by their perception of urban garbage being dumped in a rural setting. Additional truck traffic and real and perceived impacts make siting any kind of waste disposal facility very difficult. Energy from waste facilities are often located in more industrial settings, closer to city centers. Their siting is certainly not free of opposition, but they tend to generate less angst.
The waste hierarchy ranks waste management options in order of preference: reduce, reuse, recycle, recover, and finally, dispose. Using waste as a fuel has benefits such as displacing fossil fuel and reducing the volume of waste by up to 90 percent. If sized correctly, energy from waste complements recycling (Compatibility between recycling and waste-to-energy). Research from the European Union and U.S. shows that jurisdictions with the highest recycling rates often have energy from waste facilities. When these facilities are too large, they can discourage long-term waste reduction and recycling efforts with “pay or put” contracts that require local governments to always provide a minimum amount of waste.
For best operational efficiency, energy from waste plants require upfront waste processing and recycling. Materials like PVC plastic and florescent light bulbs should be removed at source to reduce emissions. These efforts can be linked to citywide recycling and hazardous waste programs.
Moreover, energy from waste operators are keen to have these wastes removed to protect equipment and ensure safe operation. Landfills, on the other hand, tend to be more forgiving of spurious waste products, or wastes with high moisture content. Unlike energy from waste, landfills are constrained by total volume. Recycling and diverting waste can extend the life of landfills (although, similar to energy from waste, local governments that rely on waste tipping fees for overall revenue might have an incentive to accept more waste).
Landfills may be more appropriate in communities where waste tends to be high in moisture, collected erratically, and sustained regulatory oversight may be missing. For a sustainable waste management system, energy from waste also needs to be integrated with a nearby energy customer.
According to the Intergovernmental Panel on Climate Change, energy from waste is renewable, or at least climate-neutral. Although energy from waste plants emit greenhouse gases, the major portion (50 to 67 percent) of carbon is biogenic, so the combustion does not increase the total amount of carbon in the atmosphere (Solid waste management and climate change). This is because the carbon is part of the earth’s carbon cycle already. In addition, combusting one tonne of waste in an energy from waste plant prevents one ton of carbon dioxide being emitted, according to the United States Environmental Protection Agency. By comparison, landfills generate methane, which is 21 times more potent as a greenhouse-gas than carbon dioxide. Landfill gases need to be collected and combusted (also often generating energy).
In an ideal world of less waste, fewer energy from waste plants and landfills would be needed. But as waste volumes around the world are expected to double in the next 30 years, more landfills and energy from waste plants are inevitable. For peak performance, these facilities require professional management and unrelenting attention to waste separation and community involvement. Better decisions are made when the public is part of the decision making process and supports an ongoing waste management program.
Building and siting landfills
Landfills are similar in scope and complexity to large, ongoing civil works projects. For 10 to 20 years, a landfill requires heavy machinery to compact waste, excavate, and move soil cover material. Waste managers need to ensure that there are always funds available for fuel, civil works, and liners for new cells, along with site supervision and communications with local residents. Landfills also need to be fully integrated into local land use plans. Before work starts, the final land use should be known. Will the closed site be a golf course, public green space, or used for agriculture? Local residents are more amenable to a landfill site if they know what the site’s final use will be and what the time frame is. Siting a landfill is a complicated process with many aspects to consider. Those considering this option will find more detailed, step-by-step information from Waste Treatment and Disposal.
Buying better energy from waste technology
Energy from waste plants are capital intensive, and much of the system cost is upfront. Similar to buying a car or computer, it is important to get the technology as correct and flexible for improved downstream operations as possible. The large initial contracts associated with the technology can attract unwanted political influence. When acquiring the technology or services, the local government should ensure that the selection process is as transparent as possible, with all costs over the life of the facility considered.