C. Philip Baumel, Charles R. Hurburgh, and Tenpao Lee
Previous fuel consumption studies for rail, truck, and barge freight transport are based on industry averages over all commodities. The conflicting results from these studies are of limited usefulness in predicting total fuel consumption and fuel costs for individual grain shipments.
This study measured fuel consumption in transporting grain from Iowa origins to Japan and Amsterdam by alternative routes and modes of transport and applied these data to construct equations for fuel consumption from Iowa origins to alternative final destinations.
Barge fuel consumption data were taken from daily towboat logs for 11 tows on the Upper Mississippi River, and 16 southbound and 19 northbound tows on the Lower Mississippi River. Ocean vessel fuel consumption was estimated from data for 254 ocean vessels obtained from The Journal of Commerce and Commercial and The Bulk Carrier Register, 1982. The unit-train data were taken from six metered trips to West Coast ports and four metered trips to New Orleans (NOLA). The truck data were taken from three metered trips to Muscatine, Iowa. In addition, the company owning the metered truck provided records on 1983 fuel consumption for seven trucks with the same specifications as the metered truck but pulling flat trailers rather than hopper-bottom trailers.
Regression analyses related total fuel consumption to various vehicle and operating characteristics. The results of the fuel tests and regression equations were used to predict fuel consumption from Iowa origins to Yokohama, Japan, and Amsterdam, Netherlands, via alternative routes and modes. The results are as follows:
- The metered tractor-trailer truck averaged 186.6 gross ton-miles per gallon and 90.5 net ton-miles per gallon when loaded 50 percent of total miles. The truck averaged 249.6 gross ton-miles per gallon when loaded and 108.8 gross ton-miles per gallon when empty. The 90.5 net ton-miles per gallon is 41.4 percent higher than the 64 net ton-mile estimate from a 1977 study of 25-ton trucks with 50 percent loaded miles.
- The 1983 fuel consumption of the seven trucks taken from company records was 82.4 net ton-miles per gallon at 67.5 percent loaded miles and 68.6 net ton-miles per gallon at 50 percent loaded miles. Net ton-miles per gallon increased sharply with higher backhauls. The trucking company executives believe that the difference between the metered and the company record net ton-miles per gallon was largely due to driver performance.
- Unit grain trains from Iowa to West Coast ports averaged 437.0 net ton-miles per gallon whereas unit grain train s from Iowa to New Orleans averaged 640.1 net ton-miles per gallon--a 46 percent advantage for the NOLA move. All trains returned empty.
- Average barge fuel consumption on the Mississippi River from Iowa to NOLA export grain elevators was 544.5 net ton-miles per gallon, with a 35 percent backhaul rate.
- On the Upper Mississippi River, southbound tows achieved 953 net ton-miles per gallon with all barges loaded while the northbound tows achieved only 243 net ton-miles per gallon with a 37.7 percent backhaul.
- On the Lower Mississippi River, southbound tows achieved 1,290 net ton-miles per gallon with all barges loaded while northbound tows averaged only 185 net ton-miles per gallon with a 31.5 percent backhaul.
- Barge net ton-miles per gallon are highly related to the percentage of backhaul. As backhaul increases from zero to 35 percent, net ton-miles per gallon increase 37 and 22 percent on the Upper and Lower Mississippi rivers, respectively.
- Ocean vessel net ton-miles per gallon varies widely by size of ship and backhaul percentage. With no backhaul, the average net ton-miles per gallon were as follows:
Size of ship
Net ton-miles per gallon|
- The most fuel efficient route and modal combination to transport grain from Iowa to Japan depends on the size of ocean vessel, the percentage of backhaul, and the origin of the grain. Alternative routes and modal combinations in shipping grain to Japan are ranked in descending order of fuel efficiencies as follows when similar-sized ocean vessels and typical ocean vessel routes are used.
Figure 1. Estimated Gallons of Fuel to transport one ton of grain from Boone, Iowa to Yokohama, Japan by alternative routes and modes.
- Unit trains direct to West Coast ports.
- Unit trains direct to NOLA and the unit-train-barge combination with 100 percent barge backhaul.
- Unit-train-barge combinations with less than 100 percent backhaul. The barge movements in this analysis had an average of 35 percent backhaul.
- Truck-barge combination with 100 percent truck backhaul.
- Truck-barge combination with zero percent truck backhaul.
Figure 1 shows the total gallons of fuel consumed per short ton (2,000 pounds) of grain transported from central Iowa to Japan for the alternative modes and routes using a 50,000 dwt ocean vessel. Fuel consumption data from the metered truck were used in all estimates based on the company records had been used in place of the metered truck data, the impact would have been zero, whereas from Boone, the metered trucks would have added 0,3 gallon of fuel per ton of grain.
- There is a little difference in total fuel consumption among the following three modal combinations in shipping grain from Iowa to Japan.
- Unit grain trains to West Coast ports and 50,000 dwt vessels with 50 percent loaded miles.
- Unit grain trains direct to NOLA and 30,000 dwt ship with 100 percent loaded miles.
- Unit grain trains to barge-loading elevators on the Mississippi river, barges to NOLA with 100 percent backhaul, and 30,000 dwt ship with 100 percent loaded miles.
- A 50,000 dwt vessel consumes almost one more gallon of fuel to haul one short ton of grain from Tacoma to Japan than does a 70,000 dwt vessel. A 50,000 dwt ship uses about 1.7 more gallons of fuel per short ton than a 100,000 dwt vessel. It is not possible, however, to move 70,000 to 100,000 dwt vessels through the Panama Canal.
- Under most scenarios, the most fuel efficient route for shipping Iowa grain to Japan is through West Coast ports for all Iowa origins. For a variety of reasons, however, this has historically not been the most cost efficient route.
- Larger ocean vessels also reduce the fuel consumption in shipping grain from NOLA to Amsterdam. On the NOLA-Amsterdam route, 70,000 and 100,000 dwt vessels use 1.2 and 2.3 fewer gallons of fuel per ton than 50,000 dwt vessels. The ports of Amsterdam, Rotterdam, and Antwerp can take fully loaded 100,000 dwt ships. The 40-foot draft at NOLA ports, however, will not permit a 100,000 dwt ship to be fully loaded there .
Figure 2. Estimated Gallons of Fuel to transport one ton of grain from Boone, Iowa to Yokohama, Japan by alternative routes and modes*.
- Figure 2 shows the fuel cost, at mid-1984 fuel prices, to transport one ton of grain to Japan for most modal combinations.
- For 30,000 dwt ocean vessels, the West Coast option had the lowest fuel cost for all Iowa origins.
- For 50,000 dwt ocean vessels, the West Coast option had the lowest fuel cost per ton of grain for all Iowa origins in the analysis except Burlington. From Burlington, unit trains direct to NOLA had a slight fuel cost advantage over the West Coast option.
- The lowest fuel cost options from Burlington to Japan with 70,000 dwt ocean vessels are unit train direct to NOLA and unit-train-barge with a 100 percent backhaul. From Cedar Rapids to Japan, NOLA had the lowest fuel cost with unit trains direct to NOLA and with the unit-train-barge combination with a 100 percent barge backhaul.
- Figure 2 shows the estimated fuel cost to transport one short ton of grain from central Iowa to Japan for the alternative routes and modes by using a 50,000 dwt ocean vessel.
- The West Coast fuel cost advantage decreases if the cost of diesel fuel used by railroads and barges increases relative to the less refined fuels used ocean vessels, and conversely, the Wet Coast fuel cost advantage will increase if the cost of railroad diesel fuel declines relative to the cost of less refined ocean vessel fuel.
The analysis deals only with limited samples of truck, barge, and rail grain shipments, each using somewhat different methods of measuring fuel consumption. These results should not be used for other commodities, vehicles, vessels, or routes.