Saturday, September 11, 2010

Transport Fuel Rationing: Part 3: Gasoline and Diesel availability per Household

Of course, those total daily gasoline and dfo (diesel) amounts that I estimated in Part II are not all available for American households to use for their own personal transportation. We have to subtract, off the top, various "critical uses" for these fuels, such as uses by the government (federal state, county and city), for commercial transport, and for other commercial and industrial uses.

I have estimated these critical uses for gasoline and dfo separately below:

Gasoline Critical Uses
Gaines et al. estimated that commercial trucks use 14 billion G of gasoline per year (slide 4; http://www.transportation.anl.gov/pdfs/TA/374.pdf).  This translates into about 38 MG/d, or about 10% of the total daily use of gasoline (368 million gallons gas per day).

The AER 2009 reported that commercial sector and industrial sector use of motor gasoline in 2009 was 46 trillion Btu (Table 5.14a) and 249 trillion Btu (Table 5.14b) respectively. There are 124,262 Btu/gallon of gasoline (http://www.eia.doe.gov/neic/infosheets/apples.html) and 365 d in a year, so this converts into 1 MG/d and 5.5 MG/d, or combined total of about 1.8% of the total daily use of gasoline.

The AER 2009 reports that the federal government (including the DoD) use of motor gasoline in 2009 was 49 trillion Btu (Table 1.12), which converts into about 1.1 MG/d, or about 0.3% of the total daily use of gasoline

I could not find good summary statistics on state and city gasoline use. But I did I find information on the number of fleet vehicles operated by the state and local governments. The total number of state, county and local, and police. fleet cars and a trucks in the USA equals about 4.9 million vehicles (http://www.government-fleet.com/Statistics/StatsViewer.aspx?file=http%3a%2f%2fwww.government-fleet.com%2ffc_resources%2fstats%2fAUTOF-9.pdf&channel=)  which is about 1.9% of the total number of 255 million registered vehicles in the USA (http://www.bts.gov/publications/national_transportation_statistics/html/table_01_11.html).  I have assumed that these government vehicles would on average use the same proportion (1.9%) of gasoline per day as other vehicles. This would correspond to about 7 MG gas/day.

Now I can to tally up the gasoline for these critical uses, on a percentage basis:
commercial trucks: 10%
commercial and industrial: 1.8%
government (total federal, state, county and local): 2.2%

Therefore, I estimate a total of about 14% of the gasoline supply, or about 52 MG gas/d is needed for these critical uses, and is not used by, or available to, households.

DFO Critical Uses
The AER 2009 also provides estimates of the sector-by-sector dfo use:

Non-Transportation Uses:
Residential use (table 5.13a):                 286 kB dfo/d = 12 MG dfo/d
Commercial use (table 5.13a):                159 kB dfo/d = 6.7 MG dfo/d
Industrial use (table 5.13b):                    547 kB dfo/d = 23 MG dfo/d
Electric power generation (table 5.13):      31 kB dfo/d = 1.3 MG dfo/d
                                                                       total = 43 MG dfo/d
Transportation Uses:
Transport (table 5.13c):                      2605 kB dfo/d = 109 MG dfo/d

(Parsimony check: The total dfo for non-transport and transport uses equals 152 MG dfo/d, which agrees pretty well with that dfo supply number from table 5.11 of 152 MG dfo/d).
(Notice that the Non-transport sectors amount to 28% of the daily use of dfo. This is much more than the non-transport uses for gasoline which only amounted to a few percent.)

I can further break down the transport sector, based on Gaines’s estimated that commercial trucks use 24 billion G of diesel per year (slide 4; http://www.transportation.anl.gov/pdfs/TA/374.pdf).  This translates into about 66 MG dfo/d, which is 43% of the daily use of dfo, and over 60% of the daily transportation use. Again, this is much more than the trucking uses for gasoline, which I estimated to be 10% of the total daily use of gasoline.

Additionally, I took the 2008 figures for dfo sales for railroad and vessel bunkering use (Table 5.15; 6.6% of the total dfo for 2008) and applied this on a percentage basis to the 2009 total dfo use:

Railroad and Vessel bunkering uses: 0.066 x 152 MG dfo/d = 10 MG dfo/d

Government Use:
The AER 2009 estimated that the federal government (including the DoD) use of dfo in 2009 was 169 trillion Btu (Table 1.12), which converts into about 3.4 MG dfo/d, or about 2.2% of the total daily use of dfo. Again, this is a larger fraction than the federal government’s daily use of gasoline, which I estimated to be about 0.3%.

Absent any statistics on state and local government dfo use, I made the same estimate as I did for gasoline: the total number of state, county and local, and police, fleet cars and trucks corresponds to 1.9% of the vehicles in the USA and would on average use the same proportion (1.9%) of dfo per day as other vehicles, or about 1.6 MG dfo/day. This may be an underestimate if the state and local government’s use of dfo trends in the same direction as the federal government’s.

This gives the estimated total government daily use of dfo to be about 7 MG dfo/d or about 4.5% of the total daily use.

Tallying up these Critical Uses gives the following:
Non-transport:                       43 MG dfo/d
Truck, Rail, Vessel transport: 76 MG dfo/d
Government:                           7 MG dfo/d
                                 Total: 126 MG dfo/d

Notice that the total percentage of critical use dfo uses 83% (i.e, 100%*(126 MG dfo/d)/(152 MG dfo/d)) is much higher than the percentage (14%) needed for gasoline critical uses.

Daily Household Use of Gasoline and Diesel
In the USA, there are about 105 million households (http://quickfacts.census.gov/qfd/states/00000.html), and, there are about 2 cars per household (http://www.autospies.com/news/study-finds-americans-own-2-28-vehicles-per-household-26437/).

From this I can estimate that the present use of gasoline and diesel per household per day, after substracting out the critical uses:
368 MG gas/d – 52 MG gas/d = 316 MG gas/d

The use of gasoline per household per day therefore equals:
(316 million gallons gas per day)/ (105 million households) = 3.0 gallons of gas per day per household (G gas/d•hh).

Assuming an average vehicle efficiency of about 20 miles per gallon (see e.g., Table 2.8 of the AER 2009; cars and trucks average about 22 and 18 mpg, respectively) , that would give the average household an average daily driving range of about 60 miles (3 G x 20 mi/G).


This range is just slightly less than a one-way average commuter distance of 16 miles per vehicle reported in a 2005 poll (http://abcnews.go.com/Technology/Traffic/story?id=485098&page=1).  That is, a two-vehicle household each commuting a round trip of 32 miles, would travel 64 miles per day. However, this might balance out because commuting would probably only be for five days a week.

This range also is slightly less than the EPA's estimate that number of miles driven per year is assumed to be 12,000 miles for all passenger vehicles (http://www.epa.gov/oms/climate/420f05004.htm), which gives an average of 32 miles per day per vehicle, or about 64 miles per day for the average 2-vehicle house hold.

Doing the same calculation for diesel,  after substracting out the critical uses, gives:
152 MG dfo/d - 126 MG dfo/d = 26 MG dfo/d,  or,
(26 MG dfo/d)/(105 million households) = 0.25 gallons of dfo per day per household (G/d•hh).

That's a lot less diesel available per houshold than gasoline.

Some Preliminary Observations
In Part 4 we will get to my hypothetical disruption event, but I want you to look at this graph comparing the present uses of dfo and gasoline:

There are a couple of points worth noting here:
  1. There is a lot less diesel (152 MG dfo/f) than gasoline (368 MG gas/d); this just follows from the fact that in the USA less diesel than gasoline is refined per barrel of oil.
  2. Despite there being less diesel than gasoline, truck transportation uses more diesel than gasoline, plus, there are substantial uses for railroad and bunker vessel transportation.
  3. There are substantially more non-transportation uses for diesel than gasoline.
  4. Consequently, as I noted above, the critical uses of diesel are a much larger proportion of the total (83%) than for gasoline (14%).
Do you start to sense the problems in store for non-critical uses of diesel by households if there was an import disruption?
Hint: look at who you would be completing against for those remaining gallons of diesel.

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