Estimated Emissions from the Prime-Movers of Unconventional Natural Gas Well Development Using Recently Collected In-Use Data in the United States

Natural gas from
shale plays dominates new production and growth.
However, unconventional well development is an energy intensive process.
The prime movers, which include over-the-road service trucks, horizontal
drilling rigs, and hydraulic fracturing pumps, are predominately powered
by diesel engines that impact air quality. Instead of relying on certification
data or outdated emission factors, this model uses new in-use emissions
and activity data combined with historical literature to develop a
national emissions inventory. For the diesel only case, hydraulic
fracturing engines produced the most NOx emissions, while drilling engines produced the most CO emissions,
and truck engines produced the most THC emissions. By implementing
dual-fuel and dedicated natural gas engines, total fuel energy consumed,
CO2, CO, THC, and CH4 emissions would increase,
while NOx emissions, diesel fuel consumption,
and fuel costs would decrease. Dedicated natural gas engines offered
significant reductions in NOx emissions.
Additional scenarios examined extreme cases of full fleet conversions.
While deep market penetrations could reduce fuel costs, both technologies
could significantly increase CH4 emissions. While this
model is based on a small sample size of engine configurations, data
were collected during real in-use activity and is representative of
real world activity.