Economies of Scale in Ocean Shipping and U.S. Retailers’ Response to Pandemic Supply Chain Problems

Beginning in the 1950s, several companies pioneered in developing modern shipping containers that once arrived at docks can be lifted by cranes and directly attached to trucks or loaded on to trains for overland shipping. As economist Marc Levinson was the first to discuss in detail in his 2004 book, The Box, container shipping, by greatly reducing transportation costs, helped to make the modern global economy possible. (We discuss globalization in Economics, Chapter 9, Section 9.1 and Chapter 21, Section 21.4, and in Macroeconomics, Chapter 7, Section 7.1 and Chapter 11, Section 11.4.) 

Lower transportation costs meant that small manufacturing firms and other small businesses that depended on selling in local markets faced much greater competition, including from firms located thousands of miles away. The number of dockworkers declined dramatically as the loading and unloading of cargo ships became automated. Ports such as New York City, San Francisco, and Liverpool that were not well suited for handling containers because they lacked sufficient space for the automated equipment and the warehouses, lost most of their shipping business to other ports, such as Los Angeles, Seattle, and London. Consumers in all countries benefited because lower transportation costs meant they were able to buy cheaper imported goods and had a much greater variety of goods to choose from.

In the decades since the 1950s, shipping firms have continued to exploit economies of scale in container ships. (We discuss the concept of economies of scale in Econimics and Microeconomics, Chapter 11, Section 11.6.) Today, shipping containers have been standardized at either 20 feet or 40 feet long and the largest ships can haul thousands of containers. Levinson explains why economies of scale are important in this industry:

“A vessel to carry 3,000 containers did not require twice as much steel or twice as large an engine as a vessel to carry 1,500. [Because of automation, a] larger ship did not require a larger crew, so crew wages per container were much lower. Fuel consumption did not increase proportionally with the vessel’s size.”

To take advantage of these economies of scale, the ships needed to sail fully loaded. The largest ships can sail fully loaded only on routes where shipping volumes are highest, such as between Asia and the United States or between the United States and Europe. As a result, as Levinson notes, the largest ships are “uneconomic to run on most of the world’s shipping lanes” because on most routes the costs per container are higher for the largest ships for smaller ships. (Note that even these “smaller ships” are still very large in absolute size, being able to haul 1,000 containers.) 

Large U.S. retail firms, such as Walmart, Home Depot, and Target rely on imported goods from Asian countries, including China, Japan, and Vietnam. Ordinarily, they are importing goods in sufficient quantities that the goods are shipped on the largest vessels, which today have the capacity to haul 20,000 containers. But during the pandemic, a surge in demand for imported goods combined with disruptions caused by Covid outbreaks in some Asian ports and a shortage of truck drivers and some other workers in the United States, resulted in a backlog of ships waiting to disembark their cargoes at U.S. ports. The ports of Los Angeles and Long Beach in southern California were particularly affected. By October 2021, it was taking an average of 80 days for goods to be shipped across the Pacific, compared with an average of 40 days before the pandemic.

Some large U.S. firms responded to the shipping problems by chartering smaller ships that ordinarily would only make shorter voyages. According to an article in the Wall Street Journal, “the charters provide the big retailers with a way to work around bottlenecks at ports such as Los Angeles, by rerouting cargo to less congested docks such as Portland, Ore., Oakland, Calif., or the East Coast.”  Unfortunately, because the smaller ships lacked the economies of scale of the larger ships, the cost the U.S. firms were paying per container were nearly twice as high. (Note that this result is similar to the cost difference between a large and a small automobile factory, which we illustrated in Economics and Microeconomics, Figure 11.6.)

Unfortunately for U.S. consumers, the higher costs U.S. retailers paid for transporting goods across the Pacific Ocean resulted in higher prices on store shelves. Shopping for presents during the 2021 holiday season turned out to be more expensive than in previous years. 

Sources: Marc Levinson, The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger, Second edition, Princeton, NJ: Princeton University Press, 2016; Sarah Nassauer and Costas Paris, “Biggest U.S. Retailers Charter Private Cargo Ships to Sail Around Port Delays,”, October 10, 2021; and Melissa Repko, “How Bad Are Global Shipping Snafus? Home Depot Contracted Its Own Container Ship as a Safeguard,”, June 13, 2021. 

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