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Greenhouse Gas Research Areas
Sources and Sinks
The emissions programs in APB are primarily dedicated to anthropogenic (human-influenced)
sources of methane and high-global-warming refrigerants, though some work
addresses carbon dioxide (CO2) by virtue of the influence of biomass
as a CO2 sink and the impact of photovoltaic energy on emissions
from fossil fuel power plants. Capabilities exist for characterization of
anthropogenic emissions from sources such as landfills, coal mines, natural
gas systems, wastewater, animal waste lagoons, biomass combustion, nitrous
oxide (N2O) and supermarket refrigerant leaks. Some of this emission
characterization work is described below.
Field Sampling Capability
Having successfully used FTIR spectroscopy to measure methane emissions from
surface coal mines and landfills and recognizing the broad range of analytical
capabilities of FTIR, APPCD is developing an in-house capability to apply
FTIR to a variety of measurement situations. APPCD has a bistatic Model 240
Midac 0.5 cm, one infrared spectrometer with a 10-in. (25 cm) telescope (all
mounted on an auto-positioning turret), two 20-in. (51 cm) IR sources, and
a Climatronics Tacmet weather station with wind speed and direction, ambient
temperature, and barometric pressure sensors for obtaining site-specific meteorological
data. The addition of two more IR sources now permits the unit to be operated
in the newly developed plane-integrated mode, as well as the conventional
single-path mode. The plane-integrated technique resolves some of the uncertainty
caused by the single-path technique's inherent sensitivity to vertical plume
dispersion by lessening the dependence on modeling techniques for determining
plume concentrations in the vertical plane. Instrument testing and methodology
development has occurred first at a series of animal waste lagoons and later
at landfill sites. Field sampling has been performed primarily in the natural
gas and coal mining industries and may be evaluated in the petroleum industry.
Methane Emissions from the Natural Gas Industry
Methane emissions from the natural gas industry have been estimated to be
anywhere from 25 to 45 Tg/yr globally. This degree of uncertainty has made
the use of these estimates inadvisable in modeling efforts or fuel switching
strategy evaluations. The lack of sector-specific measurements has also made
the identification of mitigation targets problematic.
APB developed the first estimate of methane emissions from the domestic gas industry that is based on an extensive new database developed specifically for the effort and which is produced and presented within a sound statistical framework. This more precise estimating procedure permits modelers to significantly improve their estimates of methane emission sources in the area of fossil fuel cycles.
Emissions Software
APB has been active in evaluating GHG emissions since 1988. As part
of this program, existing software has been evaluated to determine
applicability for our purposes and, where prudent, software for
internal use has been written and utilized. At this time, the MARKAL
family of software is being used. Existing database information is
being augmented by additional data on current and new technologies in
the transportation and electricity generation areas. Technology
scenarios for plausible future technology mixes are being evaluated.
For selected scenarios, environmental stressors for the technologies will
be evaluated. The emissions information is intended to be input to air
quality studies to determine possible effects of climate change on air
quality in future years. In addition, specialized evaluations may be
performed on a more regionalized basis to aid decision makers in selecting
technology paths that have a higher probability of meeting long-term
societal needs economically with acceptable environmental stressors.