Comment
02-APR-2006
The
waste industry can maximize its potential for reducing greenhouse gas emissions
by assuring the quality of waste-derived fuels and optimizing WTE technologies,
says Susanne Rotter
The latest projections from the European Environment Agency show that the existing
emissions policies of EU Member States will yield a total emissions reduction
of only 4.7% by 2010, far short of targets. Under the Kyoto Protocol, the EU
is required to cut its combined emissions of carbon dioxide and five other greenhouse
gases (GHGs) to an average of 8% below 1990 levels by 2008¿2012. One year after
the EU Emissions Trading Scheme (ETS) was established, it is appropriate now
to examine how waste management has contributed to GHG emissions and how the
industry can make an active contribution to energy savings and GHG reduction
in order to reach Kyoto targets.
Within the waste sector, landfills have the highest impact on climate change.
In the EU, methane emissions from waste disposal on land accounted for 1.6%
of the 4 million tonnes of CO2-equivalent GHG
emissions in 2002.
The generation of GHGs from existing landfills is unavoidable, but emissions
can be reduced by technical measures. The cost of implementing such measures
is very low. Approximately 10 years after landfill closure, the specific costs
for gas mitigation per tonne of reduced CO2-equivalent
usually range between ¿2 and ¿15. Bearing in mind that EU Allowances
are currently being traded at about ¿20¿25/tonne CO2,
it is not surprising that nearly 25% of all UNFCCC Clean Development Mechanism
(CDM) projects are landfill gas projects.
Between 1990 and 2002, methane emissions from managed landfills in the EU declined
by 32%. This significant reduction is due to the impact of two strategies: first,
a decline in the amount of biodegradable waste going to landfills; and second,
the increasing amount of recovered landfill gas which is utilized or flared.
The German waste sector exemplifies this progress. From 1990 to 2003, annual
GHG emissions from landfills declined from 31 to 11 million tonnes, with a further
reduction of 8 million tonnes expected by 2012. In total, this equates to a
reduction of more than 90%. Although in 1990 nearly 70% of Germany¿s residual
waste was landfilled, since 1 June 2005 the Waste Storage Ordinance ¿ Germany¿s
implementation of the 1999 EU Landfill Directive ¿ has allowed only incinerated
waste or waste pretreated by mechanical¿biological treatment to be landfilled.
Along with Austria, Denmark and the Netherlands, the German waste industry is
assuming a pioneering role in implementing the Directive. While problems remain
with insufficient treatment capacities and intermediate storage options, the
German Waste Storage Ordinance can be regarded as a success story for mitigating
climate change. And in the next decade, similar trends can be predicted for
other European countries.
In contrast with primary production using virgin materials, energy recovery
and materials recycling also result in emissions mitigation. `Waste-to-energy¿
is the keyword in this context. Nearly all thermal treatment plants produce
energy in the form of electrical power or thermal heat. Compared with other
fossil fuels, household and commercial wastes have a significantly lower CO2-emission
factor due to the biogenic carbon content derived from paper, wood and textiles.
There is scope for improving the efficiency of energy conversion using waste-to-energy
¿ for example, thermal treatment plants in Germany currently only show an average
efficiency in net electrical power production of 13%. If we invest in energy
efficiency for existing plants, we can reduce GHG emissions. Every additional
kilowatt-hour of energy produced from waste can contribute to this reduction.
The substitution of fossil fuels by refuse-derived fuel (RDF) is proving profitable,
particularly in the area of combined heat and power (CHP). Growth in the CHP
sector has made it possible to consider plants powered by more than 500,000
tonnes of RDF per year, which was unimaginable just a few years ago. But there
are also technical challenges still to be solved, and these concern fuel handling,
boiler and kiln maintenance, flue gas cleaning and the quality of by-products.
It is vital to attain an appropriate quality of RDF, otherwise the real operational
availability of this technology will be much smaller than the high energy demands
required by industrial sectors.
Technical obstacles are not the only ones inhibiting the efficient use of electrical
and thermal energy. For example, in Germany, waste-to-energy is not considered
a type of renewable power and there are no economic incentives for its use.
By contrast, the extension of a waste-to-energy plant in Amsterdam and the achieved
electrical efficiency of more than 30% show how guaranteed revenues for produced
power can promote highly energy-efficient technologies.
The strict avoidance of landfilling and having a clear policy framework for
waste-to-energy in all Member States will help Europe open up new potential
in reducing GHG emissions. However, to guarantee our manufacturing industry
a safe and full supply of green energy from the waste industry, we still need
to understand more about how to improve the quality of the new fuel products
and how to optimize combustion technologies.
DR SUSANNE ROTTER is Professor and Head of the
Department of Waste Management at the Technical University of Berlin, Germany.
e-mail: rotter@itu301.ut.tu-berlin.de
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