Waste-to-energy (WTE) is the incineration of waste with the recovery of energy in the form of electricity and/or heat. There has been enormous technological development of WTE since the eighties, especially with regard to the Air Pollution Control systems used in modern WTEs. In the environmental impact hierarchy of waste management, WTE has taken its place under recycling and above landfilling. Numerous studies have been done that show WTE’s superiority over disposal in landfills in terms of greenhouse gas (GHG) emissions and environmental impact. Landfills emitted about 126 Teragrams (1 Teragram is 1012 grams or one million metric tons) of CO2 equivalents in 2008 and are the second biggest emitter of methane in the country (first place goes to cow dung).
On a per mass basis, methane (CH4) has a Global Warming Potential of 23 times that of CO2. So it makes total sense to collect all the methane we can. Actually, many landfills in the U.S. flare all the methane they collect, just to convert it to CO2 and reduce the impact on global warming. Better however, is to extract embodied energy from it by combusting it in for instance a turbine.
Globally, around 600 WTE plants are operating, most of them in Europe (431) and 87 in the US. Most of the U.S. plants were built in times of higher energy prices and landfill tipping fees, from 1980 to 1995. After this, WTE plants were only expanded or retrofitted. However, in the rest of the world, especially in Europe but also in Japan and China, WTE plants popped up from the ground like mushrooms. Some EU-countries have reduced the share of landfilling in waste processing to less than 5% because of regulations banning landfilling of compostable or combustible waste. They increased their recycling efforts and also built WTE plants to burn the leftovers and recover valuable energy. So why didn’t this happen in the US?
Reasons for the non-implementation
Knowledge gap
The Waste-to-Energy technology can be tagged as one of the big victims of the lack of adequate information channels from engineers to politicians. The WTE knowledge acquisition rate of decision makers is as slow while the technological development in WTE has been fast. Politicians and many environmentalists tend to still associate waste incineration with dirty smoke stacks and severe health issues.
This may have been true for the state of the technology 25 years ago, but it is not now. Modern WTE plants are equipped with sophisticated air pollution control systems that greatly reduce harmful emissions in the stack gases. For example, dioxins emissions from MSW incineration processes are often mentioned as arguments against WTE, but these have been reduced by 99.86% in the past two decades, now representing only 1% of all dioxins emissions (Deriziotis, 2004). Mercury emissions from WTE have also been reduced significantly: Coal fired power plants in the U.S. emit a total of 40 times more mercury than all WTE plants together. Also, cadmium, lead, sulfur dioxide and particulate matter emissions have all been reduced by 90 – 95%, as compared to 1990 levels.
Regrettably, this information has not yet reached the decision making parties in many US states. Therefore,, WTE in the U.S. has not received the financial incentives that it needs in order to replace landfilling, as has been done in other developed nations..
Land availability and regulations
Landfills in or near municipalities are not often found in the US. They are located far from the source of generation, where land is inexpensive and also to prevent odors from reaching the people. In this way, n people do not complain and the tipping fees can be kept low. In Europe, many countries regulate landfills strongly by apply big taxes on landfilled waste. In Japan, disposal of waste in landfills is prohibited. This is intended to reduce the long term environmental impacts of landfills, in particular emission of greenhouse gas, and to reduce land area ‘wasted’ by landfills. It is often seen that highly populated areas, with high groundwater levels are more likely to ban landfills. Landfilling does not only affect the area of the landfill itself, it also reduces value of surrounding properties.
WTE has been shown to reduce the volume of material to be disposed by 90 % of the input volume. In Europe, the residual bottom ash is usually mixed cement to form concrete structures or ise used as road base or in embankments. Thus, the total volume of waste is reduced to practically zero. However, in the US, only 7 percent of bottom ash is used: the rest is used for landfill maintenance, e.g. as Alternative Daily Cover, or simply landfilled (wasteage.com 2009). Although the leftover material use has not reached its full benefit in the US, the tonnage that needs to be landfilled is reduced to great extent after incineration.
Because of the presumed abundance of land in the U.S., there is no direct need to prohibit disposal of waste in landfills and landfill gate fees in many states are ridiculously low. It is therefore difficult for WTE facilities to penetrate the waste disposal market, mainly because of their very high capital costs.
High costs
The taxes added to landfill tipping fees in Europe have made WTE competitive in the waste processing scene. The landfill tipping fees in Europe rose to around 130 euro/ton. This is approximately four times higher than in much of the U.S. In the US. WTE has a high total cost per ton processed of around $80/ton (ccgovernment, 2009). The current landfill tipping fees in the US ($42/ton, BioCycle 2008) are therefore too low for WTE to be competitive, since the so-called external costs (e.g. greenhouse gas emissions) are not factored in. The right conditions do exist in some regions. For example, New York City is so far away from landfills that it pays about $100 per ton of MSW landfilled. Nearly 2.5 million tons of residential MSW are landfilled annually and only 0.5 million tons are sent to the Essex County WTE to be incinerated.
If the government were to decide to add a tax on landfilling, this will have a positive impact on WTE adoption. President Obama declared in October 2009 that WTE is considered ‘renewable’ (Whitehouse.gov, 2009) and should therefore be provided with financial incentives. Let us see when it happens.
EPA.gov, 2008
http://www.epa.gov/methane/sources.html
Deriziotis, 2004
http://www.seas.columbia.edu/earth/wtert/sofos/Deriziotis_thesis_final.pdf
Wasteage.com, 2009
http://wasteage.com/mag/waste_ash_rise_united/
ccgovernment, 2009
http://ccgovernment.carr.org/ccg/pubworks/sw-future/docs/status-report-wte.pdf
Whitehouse.gov, 2009
http://www.whitehouse.gov/assets/documents/2009fedleader_eo_rel.pdf
No comments:
Post a Comment