Acid rain, caused primarily by emissions of nitrogen and sulfur oxides (NOx
and SOx), is already having an environmental and economic impact
in the countries of Northeast Asia. The problem is regional in scope, as
emissions cross national boundaries and can have impacts in other nations.
Projected growth in energy consumption in the region, particularly in the
now-developing economies, creates the potential for vastly increased emissions
in coming decades. This paper reviews a selection of options for reducing
NOx and SOx emissions in five categories: post-combustion
pollution control, burner modification, fuel pre-treatment, fuel-switching,
and energy efficiency improvement. The relative cost per unit of emissions
reduction of measures from each category are compared. A number of different
options for regional cooperation to address SOx and NOx
emissions reduction are suggested, as are particular opportunities for collaboration
between the United States and Japan to assist countries of the region in
reducing emissions.
Executive Summary
Of the many environmental concerns currently facing the nations of Northeast
Asia, the problem of "acid rain" or "acid precipitation"
presents perhaps the most potent combination of immediate and ongoing impact
and regional scope. Acid rain in Asia has already been implicated in the
declining health of some of the region's forests, in the premature weathering
of metals and other man-made materials, and in the degradation of irreplaceable
cultural monuments. Acid precipitation is primarily the result of the reaction
of oxides of sulfur and nitrogen (SOx and NOx) the
"acid gases"-with water or water vapor, yielding sulfuric and
nitric acids. Acid gases can act as local air pollutants, or, depending
on weather conditions and how they are emitted, can be transported for hundreds
of kilometer or more. Acid gases are produced primarily when fuels are combusted,
although smelting of the ores of some metals is also a significant source
of sulfur oxides.
The recent and projected growth in economic output and fuels use in Northeast
Asia creates both a challenge and an opportunity. The challenge is that
unless changes are made in the way that fuels are used, acid rain and other
environmental problems threaten to seriously erode (literally and figuratively)
the gains of development. The projected increase in fuels use does, however,
provide an opportunity for the countries of the region, in cooperation,
to promote a development path for the developing nations of Northeast Asia
that takes advantage of a suite of available measures, measures that not
only reduce acid gas emissions, but can concurrently provide other environmental
and economic benefits.
The types of measures available to reduce the quantities of acid gases emitted
from the energy sector include:
"Post-combustion" or "end-of-pipe"
measures designed to remove SOx or NOx by reaction
of the acid gas with a chemical and/or a catalyst. These technologies, including
the "flue gas desulphurization" devices or "scrubbers"
now common on coal-fired plants in industrialized countries, are best suited
to utility and large industrial applications, although the catalytic converter
is an example of an end-of-pipe technology used in the transport sector.
Burner modification measures change the way that a fuel is
burned so as to avoid acid gas emissions. For sulfur oxide emissions control,
this generally means either injecting a chemical (usually lime or limestone)
into the area where the fuel is burned. NOx is more typically
controlled by manipulating the physical configuration of the burner, including
the zones where fuel and air are added in the boiler or furnace. Burner
modifications can be used on a variety of equipment, including industrial,
commercial/institutional, and some residential-scale applications. Burner
modifications are most cost-effective on new equipment, but are often also
cost effective for existing units.
Fuel pre-treatment measures that can be used to reduce acid
gas emissions include washing of coal (already widely practiced in China),
changing refinery processes to produce heavy fuel oil and diesel oil with
lower sulfur contents, or simply changing supply patterns to use lower-sulfur
imported or domestic fuels in the first place.
Fuel-switching measures that replace the use of higher-sulfur
coal or oil with low-sulfur natural gas or biomass fuels, or with electricity
generated via hydroelectric, wind, solar photovoltaic, nuclear, or other
fossil-free means.
Energy-efficiency measures that deliver the same energy
service-a liter of water heated, a passenger kilometer of travel, or
a tonne of cement produced, for example-with less fuel input than standard-efficiency
equipment.
Of these categories of measures, fuel-switching and energy-efficiency measures
hold the most promise for reducing acid gases at costs that are either relatively
low or negative (meaning that the measures pay for themselves with fuel,
capital, and operating savings alone) on a net basis. End-of-pipe and burner
modification measures are will continue to be important to retrofit the
existing equipment in the region and to the extent that growth in coal-fired
power will continue to occur. Burner modifications (such as "low-NOx"
burners) in new combustion equipment typically add little to the cost of
producing the equipment, and should be uniformly applied (as is increasingly
the practice in industrialized countries). Coal cleaning will continue to
be important to reduce the sulfur and ash content of lower-quality coals,
to improve the combustion properties of coal, and to reduce coal transport
costs. The reduction of sulfur contents of refined products is not a present
widely applicable in China, which now uses mainly low-sulfur crude oil in
its refineries, but probably will be in the future as China is forced to
purchase more and more higher-sulfur crude oil from the Middle East.
How can regional cooperation help to implement some of these measures? Possibilities
include:
Provide Information and General Training to Government Officials
to increase their understanding of the issues and support for key programs.
Provide Specific Information and Training to Local Actors so
that domestic or imported technologies can be used most effectively.
Encourage the Implementation and Enforcement of Energy and Environmental
Standards to further encourage environmentally-sustainable development.
Establish Programs of Grants and Concessional Loans to catalyze
the introduction of appropriate technologies.
Modify Existing Incentives for Energy Efficiency and Pollution
Prevention to remove social and economic roadblocks to improved practices.
Promote Joint Ventures and Licensing Agreements to start the
manufacturing of appropriate acid gas-reduction technologies in the developing
countries of the region.
Some potential starting points for United States-Japan and regional collaboration
in reducing acid gas emissions in Northeast Asia might include:
Create a clearinghouse for summary and detailed information on
acid gas reduction measures where planners, officials, plant managers,
entrepreneurs, and others can access to up-to-date information on the types
of technologies and measures are available for acid gas reduction, and how
they can be obtained.
Create a trade liaison to promote the transfer of appropriate technologies.
Promote and sponsor study tours and in-country training activities
for personnel from the developing countries of the region.
Promote and assist in applications that demonstrate promising technologies,
including providing equipment, expertise, and financial assistance.
Help to fund and organize regulatory infrastructure in China and
North Korea, including providing know-how and equipment for testing
laboratories, monitoring facilities, and research installations.
