When Incineration is a Waste-of-Energy

[Lloyd Hicks] — Fri, 15 Oct 2010 01:06:15 +0000

While we certainly can do without them, many short-lived products such as cereal boxes, soda bottles or magazines have become a necessary part of our day. Unless we dramatically change the way we live, these materials will continue to be part of the economy.

When given an option, it is clear from an environmental standpoint that we should reuse the wood fibers and plastic resins from these products instead of seeking out virgin materials. Despite this fact, when it came to an EPA comparison on options to handle municipal solid waste (MSW)[1], the life cycle benefit of recycling these materials was overlooked. Diverting more materials towards recycling can reduce the energy required for raw material extraction and manufacturing.

While recycling may have been outside the scope of the study, it is unfortunate the opportunity was missed. This may lead our towns, counties and states to believe increasing the diversion rate is not a valid option.

A New York Times article citing the EPA study also disregarded the benefits of increasing the capture rate of these materials. Instead, it focused on whether or not to recover energy from incineration or landfill gas. A couple of other studies have taken a more comprehensive view of the energy requirements of this system, and the findings support recycling before energy recovery.

The majority of the research shows recycling has fewer environmental burdens than disposal via incineration or landfilling. The findings account for energy recovery at an incinerator or through landfill gas collection (credits), as well as the energy requirements for collection, processing and transport of the recovered materials (emissions). Where do the savings come from? They appear upstream on the production side when recycled materials are used rather than energy- and material-intensive virgin feedstock. [2,3,4]

Another review of MSW studies points out methodological issues in the LCAs and finds some inconsistencies when testing the ‘waste hierarchy’ – recycling > incineration > landfilling (better to worse). However, all but one of the studies that weighted the various environmental impact categories found the waste hierarchy holds true. [5]

With the diversion rate at 33.2% in the U.S. in 2008, it is apparent that we must increase the capture rate of recyclables as well as expand what we collect at the municipal level, e.g., composting organics. But do we have the capacity to do better?

If other countries can serve as an indication, Austria, Germany, the Netherlands and Belgium have achieved diversion rates between 60 and 70 percent. These countries have high diversion rates for Europe, though they incinerate most of the residual at 27%, 35%, 39% and 36%, respectively, with the rest going to landfill. [6]

In the U.S., some communities have high diversion rates as a result of action at the legislative level. For communities with pay-as-you-throw (PAYT) programs – a system that treats garbage collection as a utility – the diversion rate for recycling is 5-6 percentage points higher, on average, than a non-PAYT community. With an additional 4-5 percentage points increase in yard waste diversion and 6 percentage points in source reduction, communities average about 16-17% less disposal under PAYT. [7]

The New York Times followed-up the article with a discussion on whether the U.S. should bury or burn its trash, with important comments on the threats to public health from Ananda Lee Tan of Global Alliance for Incinerator Alternatives and on the financial costs from Neil Seldman of Institute for Local Self-Reliance.

We have the tools at hand to increase our diversion rates and we must continue to show a preference towards recycling and composting over energy recovery from incineration and landfilling our municipal waste.

[1] Ozge Kaplan, P, DeCarolis, J, Thorneloe, S. Is It Better To Burn or Bury Waste for Clean Electricity Generation? Environmental Science and Technology. 2009; 43:1711–1717.
[2] Björklund, A, Finnveden, G. Recycling revisited – life cycle comparisons of global warming impact and total energy use of waste management strategies. Resources, Conservation and Recycling. 2005; 44: 309–317. Available from: http://dx.doi.org/10.1016/j.resconrec.2004.12.002
[3] European Environment Agency. Paper and cardboard – recovery or disposal? Review of life cycle assessment and cost-benefit analysis on the recovery and disposal of paper and cardboard. 2006; EEA Technical Report No. 5. Available from: http://www.eea.europa.eu/publications/technical_report_2006_5
[4] Morris, J. Comparative LCAs for Curbside Recycling Versus Either Landfilling or Incineration with Energy Recovery. International Journal of Life Cycle Assessment. 2005; 10(4):273–284. Available from: http://dx.doi.org/10.1065/lca2004.09.180.10
[5] Cleary, J. Life cycle assessments of municipal solid waste management systems: A comparative analysis of selected peer-reviewed literature. Environment International. 2009; 35(8):1256-1266. Available from: http://dx.doi.org/10.1016/j.envint.2009.07.009
[6] European Commission, Eurostat STAT/10/43, March 19, 2010.
[7] Skumatz, Lisa A., Ph.D. and David J. Freeman, “Pay as you Throw (PAYT) in the US: 2006 Update and Analyses”, prepared for US EPA and SERA, by Skumatz Economic Research Associates, Superior CO, December 2006.

Enrich, baby, enrich

[Lloyd Hicks] — Thu, 04 Mar 2010 04:00:11 +0000

If we focus only on what comes out of a smokestack we’re missing a key part of the supply chain for electric power. Whether the upstream activities involve oil drilling or uranium enrichment, individuals that set our energy policies should consider them.

With the recent announcement by the Obama administration to provide loan guarantees for new nuclear power plants, I thought I’d apply some life cycle thinking to energy production and test the claims on greenhouse gas emissions from nuclear power. Researchers use a life cycle approach called a full energy chain analysis (or FENCH) to quantify the impacts of the entire energy chain.

A group of Swiss researchers used the FENCH approach to model the main types of electricity production in the US (supplied by coal, natural gas and nuclear), and compared them to renewable energy production (from photovoltaic, hydropower, biomass, wind, and geothermal). Including the entire nuclear energy chain (from uranium ore extraction to radioactive waste repositories) revealed that uranium enrichment and its electricity supply is an important contributor to energy expenditures. They estimated that nuclear power in the US emits 13 g CO2-eq/kWh compared to about 1200 g CO2-eq/kWh for coal [1]. The Öko-Institute estimated 33 g CO2-eq/kWh for nuclear power in Germany [2] and an earlier study in a bulletin from the International Atomic Energy Agency found a range of 2.5-5.7 CO2-eq/kWh [3].

Clearly, nuclear power dramatically reduces CO2-equivalent emissions when compared to coal-fired power plants, but what about energy from renewable sources? Let’s consider wind power. In another study by Dones, they found that the majority of the emissions from wind power arise from the production of the materials that go into the turbine, tower and foundation – upstream activities that must be accounted for in the full energy chain. Under average European conditions, onshore wind (with a 20% capacity factor) and offshore wind (with a 30% capacity factor) emits 14 g CO2-eq/kWh. Under optimal wind conditions, an estimated 10 g CO2-eq/kWh are released. The same paper found a range of 6-12 g CO2-eq/kWh for nuclear power in Europe. [4]

Under favorable wind conditions, the studies show that wind and nuclear power emit about the same amount of greenhouse gases per kilowatt hour over the entire energy chain. Our policymakers should begin to factor in these findings before labeling nuclear power as a ‘carbon free’ energy source, and using it to advance climate change legislation. What about the price tag for this policy?

An article in Mother Jones describes some of the costs we can expect with the new plan to underwrite nuclear power. Long-term storage solutions for nuclear waste have so far escaped us, and some states are getting anxious about temporary storage.

In future posts, I’ll look into costs and the FENCH studies in more detail, and share some more findings on renewable energy.

Image: Available at: http://www.flickr.com/photos/vattenfall (Creative Commons license)

[1] Dones R., Bauer C., Heck T. (2007) LCA of current coal, gas and nuclear electricity systems and electricity mix in the USA. Proceedings of the 14th SETAC Europe LCA Case Studies Symposium, December 3-4, 2007, Gothenburg, Sweden.
[2] Fritsche UR, Lim S-S. (2006) Comparison of Greenhouse-Gas Emissions and Abatement Costs of Nuclear and Alternative Energy Options from a Life-Cycle Perspective (updated version). Öko-Institute. Available at: http://www.oeko.de/service/gemis/files/doku/nuclear_co2paper_update2006.pdf.
[3] Spadaro, J.V., Langlois, L., and Hamilton, B. (2000) “Greenhouse Gas Emissions of Different Electricity Generating Chains”, IAEA Bulletin, 42 (2).
[4] Dones R., Heck T., Hirschberg S. (2004) “Greenhouse Gas Emissions from Energy Systems, Comparison and Overview.” In: Encyclopedia of Energy (Ed. Cleveland C.), Vol. 3, pp. 77-95. Academic Press/Elsevier, San Diego, USA.

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When Incineration is a Waste-of-Energy

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