Environmental Engineering Reference
In-Depth Information
Table 4 Key additional fossil fuel combustion emissions associated with shale gas
extraction.
Process
Emissions (tCO
2
) Assumptions
Horizontal drilling
a
15-75
Horizontal drilling of 300-1500 m;
18.6 litres diesel used per metre
drilled.
Hydraulic fracturing
b
295
Based on average fuel usage for
hydraulic fracturing on eight
horizontally drilled wells in the
Marcellus Shale. The total fuel use
given is 109 777 litres of diesel
fuel.
Hydraulic fracturing
chemical production
c
-
Unknown.
Transportation of water
d
26.2-40.8
Based on HGV emission factor of
983.11 gCO
2
km
1
and 60 km
round trip.
Wastewater
transportation
d
11.8-17.9
Based on HGV emission factor of
983.11 gCO
2
km
1
and 60 km
round trip.
Wastewater
treatment
e
0.33-9.4 Based on 15-80% recovery of 9-29
million litres of water that is
required per fracturing process
and emission factor 0.406 tCO
2
ML
1
treated.
Total per well 348-438 Based on single fracturing process.
a
Fuel consumption from: ALL Consulting (2008). Emission factor from DUKES (2010).
36
b
Cited from ALL Consulting, Horizontally Drilled/High-volume Hydraulically Fractured Wells Air
Emissions Data, August 2009, Table 11, p. 10 by New York State (2009).
30
Emission factor from
DUKES (2010).
36
c
A further potential source of additional emissions may be from the production of chemical used
in the fracturing process. However, the level of these emissions is dicult to ascertain as:
conventional wells may also include various chemicals in drilling mud, so claiming shale
creates additional emissions via this route is problematic; and life cycle analysis data for these
chemicals is highly specialised and is not typically publically available.
d
Emission factor from NAEI (2010).
46
Truck numbers from Table 3.
e
Emission factor from Water UK - Towards sustainability (2006).
31
to reflect the low numbers of trac movements and minimal use by heavy
vehicles. The roads are likely to pass through small villages and towns which
are not accustomed to industrial developments. The high number of large
lorries visiting the shale gas sites during the construction phase will sub-
sequently result in deterioration of the road structure as well as generating
dust and noise associated with the trac movements. This is likely to be an
area of serious concern to the local residents along the route the trac will
take and will result in local objections at the planning approval stage. Once
the sites obtain the necessary approval, the operators of the sites could en-
counter trac movement issues as local residents and the farming com-
munity compete for road space with the construction trac which could
lead to conflict between the parties. This is an issue that the shale gas
