Geoscience Reference
In-Depth Information
1.7.8 h
ome
e
nergy
u
se
The average carbon dioxide coefficient of natural gas is 0.0544 kg CO
2
per cubic foot (USEPA
2013a), and the fraction oxidized to CO
2
is 100% (IPCC, 2006). The average carbon dioxide coef-
ficient of distillate fuel oil is 429.61 kg CO
2
per 42-gallon barrel (USEPA, 2013a), and the fraction
oxidized to CO
2
is 100% (IPCC, 2006). The average carbon dioxide coefficient of liquefied petro-
leum gases is 219.3 kg CO
2
per 42-gallon barrel (USEPA, 2013a), and the fraction oxidized is 100%
(IPCC, 2006). The average carbon dioxide coefficient
of kerosene is 426.31 kg CO
2
per 42-gallon
barrel (USEPA, 2013a), and the fraction oxidized to CO
2
is 100% (IPCC, 2006). Total single-family
home electricity, natural gas, distillate fuel oil, and liquefied petroleum gas consumption figures
were converted from their various units to metric tons of CO
2
and added together to obtain total
CO
2
emissions per home.
1.7.8.1 Calculation
Due to rounding, performing the calculations given in the equations below may not return the
exact results shown.
1.
Delivered electricity:
(11,319 kWh per home) × (1301.31 lb CO
2
per megawatt-hour deliv-
ered) × (1 mWh/1000 kWh) × (1 metric ton/2204.6 lb) = 6.8 metric tons CO
2
per home.
2.
Natural gas
: (66,000 ft
3
per home) × (00544 kg CO
2
per cubic foot) × (1/1,000 kg/metric
ton) = 3.59 metric tons CO
2
per home.
3.
Liquid petroleum gas
: (464 gal per home) × (1/42 barrels/gal) × (219.3 kg CO
2
per barrel)
× (1/1000 kg/metric ton) = 2.42 metric tons CO
2
per home.
4.
Fuel oil
: (551 gal per home) × (1/42 barrels/gallon) × (429.61 kg CO
2
per barrel) × (1/1000
kg/metric ton) = 5.64 metric tons CO
2
per home.
5.
Kerosene
:
(108 gal per home) × (1/42 barrels/gallon) × (426.32 kg CO
2
per barrel) × (1/1000
kg/metric ton) = 1.10 tons CO
2
per home.
To t a l CO
2
emissions for energy use per single-family home, then, is equal to 6.68 metric tons CO
2
for electricity + 3.59 metric tons CO
2
for natural gas + 2.42 metric tons CO
2
for liquid petroleum
gas + 5.64 metric tons CO
2
for fuel oil + 1.10 metric tons CO
2
for kerosene = 19.43 metric tons CO
2
per home per year.
1.7.9 n
umber
oF
t
ree
s
eedlings
g
roWn
For
10 y
ears
A medium-growth coniferous tree, planted in an urban setting and allowed to grow for 10 years
sequesters 23.2 lb of carbon. This estimate is based on the following assumptions:
• Medium-growth coniferous trees are raised in a nursery for one year until they become
1 inch in diameter at 4.5 feet above the ground (the size of tree purchased in a 15-gallon
container).
• The nursery-grown trees are then planted in a suburban/urban setting; the trees are not
densely planted.
• The calculation takes into account “survival factors” developed by the U.S. Department
of Energy. For example, after 5 years (1 year in the nursery and 4 in the urban setting),
the probability of survival is 68%; after 10 years, the probability declines to 59%. For
each year, the sequestration rate (in pounds per tree) is multiplied by the survival factor
to yield a probability-weighted sequestration rate. These values are summed over the
10-year period, beginning from the time of planting, to derive the estimate of 23.2 lb of
carbon per tree.
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