Buletinul Institutului Politehnic din Iași Secția Chimie și Inginerie Chimică ISSN: 2537-2947
ISSN-L: 0254-7104
2024, Volume 70(74), Issue 1 (January), pp. 59 - 68
Detection of High CH4 Concentrations at Natural Gas End-Use
Distribution Network in Urban Areas
MUSTAFA HMOUDAH, Faculty of Environmental Science and Engineering,
University of Babeş-Bolyai, Cluj-Napoca, Romania,
mustafa.hmoudah@gmail.com CRISTIAN POP, Faculty of Environmental Science and Engineering, University
of Babeş-Bolyai, Cluj-Napoca, Romania CĂLIN BACIU, Faculty of
Environmental Science and Engineering, University of Babeş-Bolyai,
Cluj-Napoca, Romania
Abstract Since the industrial revolution, CH4 emissions have
increased by 150%. Urban Areas are responsible for approximately 60% of
these emissions, mainly coming from anthropogenic activities. Besides,
urbanization caused changes in land use and reduced CH4 sinks. The sources
of CH4 emissions in Urban Areas still have a high degree of uncertainty.
Recent studies have stated that leaks from natural gas distribution networks
are significant sources of CH4 in the atmosphere, and they also represent a
potential loss of energy resources. However, emissions from end-use natural
gas networks are poorly explored in the literature. The main contributors in
the Romanian CH4 budget are the agriculture and energy sectors. Over the
period 1989–2000, methane emissions rate decreased by 34% due to sectoral
changes in agriculture and fossil fuels. Nevertheless, the Romanian national
inventory doesn’t report CH4 emissions from urban areas. This study
investigates CH4 concentration from the end-use natural gas distribution
networks in Cluj-Napoca, the second-largest city in Romania in terms of
population. These points can be identified as part of the natural gas
distribution networks that serve natural gas to end users for gas
consumption. The detected points were pipeline junctions and natural gas
meters. The estimation of CH4 concentration in the atmosphere was carried
out based on a laser CH4 sensor Tunable Diode Laser Absorption Spectroscopy
(TDLAS) with high measuring accuracy of 0.1 ppmv. This CH4 concentration
detection was performed from December 2022 to January 2023 at 74 natural gas
end-use points. The determination of whether to represent leaks or not was
quite after estimating the background level in the city and comparing the
obtained concentrations with this background. This study has revealed that
76% of the detected end-use natural gas distribution points have gas leaks
and represent continuous contributors to CH4 annual budget. However, this
contribution to the annual budget should be estimated. Moreover, the results
of this study indicate the presence of high leaks from natural gas end-use
points in urban areas. They suggest in-depth investigation and allocation of
all natural gas leaks at the end-use points, in order to take certain
reduction measures regarding CH4 mitigation. Keywords: greenhouse gas,
methane, atmosphere, urban areas, natural gas end-use networks, gas leaks.