Material Insights · Understanding the Material World

Moving energy: wires, pipes and ships: Moving molecules: pipelines, tankers, LNG and coal trains

Understanding Energy / Module 9: Moving energy: wires, pipes and ships Part 3 of 4

Moving molecules: pipelines, tankers, LNG and coal trains

Fuels have one big advantage over electricity: they can be stored on the way. A tanker at sea or a pipeline full of oil is also an inventory. But each fuel's physical form decides how it moves. Liquids are easy, gases are bulky and must be squeezed or chilled, and solids need trains, conveyors and ships.

3.1 Pipelines move oil cheaply as long as they stay full

Oil is the easiest fuel to move. It is dense, liquid at ordinary temperature and pressure, and holds about 42 MJ per kilogram. Over land, the cheapest way to move it is a buried steel pipe. Pumps push the oil from high pressure to low, and stations along the route, driven by electric motors or gas turbines, restore the pressure. A large trunk line about a metre across carries around a million barrels a day at about 8 km an hour, so oil takes some five days to travel 1,000 km.

The energy cost is tiny. Pumping a barrel 1,000 km through a large line uses roughly 4 to 5 kWh of electricity, about a quarter to a third of one per cent of the energy in the oil, according to one analyst model. Physical losses in normal operation are close to zero. In some countries theft matters more than physics: Nigeria's extractive industries audit reported 36.7 million barrels of crude stolen or lost in 2022, much of it from pipelines in the Niger Delta.

The money cost is mostly capital. A large crude line costs in the order of USD 5 million per km to build, and the toll is set to repay that over decades. A full line moves crude 1,000 km for roughly USD 2 a barrel, about USD 1.2 per MWh of oil energy; a half-empty one costs about twice as much per barrel. That is why pipeline owners want long contracts before they build, and why overruns hurt. Canada's Trans Mountain expansion cost about C$34 billion, and its fixed toll nearly doubled from the 2017 estimate.

The United States has about 228,000 miles of hazardous-liquid pipelines, which carry more than 83% of its crude and refined products. Product pipelines move petrol, diesel and jet fuel from refineries to depots, often sending different fuels one after another in the same line. The tile "Oil and product pipelines" covers the networks in more depth.

3.2 Tankers turned oil into a world market

About three quarters of the world's oil travels by sea for part of its journey: in the first half of 2025 seaborne oil trade was about 80 million barrels a day, some 76% of world supply. Smil traces how tankers grew after the 1950s, especially after the Suez Canal closures of 1956 and 1967 forced cargoes around Africa and made size pay. A very large crude carrier (VLCC) carries about 300,000 tonnes of crude, roughly 2 million barrels, on a single voyage.

These ships, like nearly all bulk carriers and container ships, are driven by large two-stroke diesel engines. Smil's account of globalisation rests on two prime movers, the marine diesel and the gas turbine, and he notes that big ships carry no backup engine, a measure of how reliable the diesels have become. Ships move freight with little energy because water supports the load and big hulls have low resistance per tonne. A VLCC round trip from the Gulf to Japan, about 50 days, burns fuel equal to roughly 0.6 to 1.6% of the energy in its cargo. Trains and river barges use under half a per cent of the cargo's energy per 1,000 km; road tankers use about three times as much as rail.

In normal markets the cost is also low. A VLCC moves crude from the Gulf to China, some 11,000 km, for about USD 2 a barrel, around USD 0.1 per MWh per 1,000 km (calculated). But freight rates swing wildly because the fleet is fixed in the short run. When war largely closed the Strait of Hormuz in 2026, VLCC day rates passed USD 1 million, and the IEA reported Gulf to Asia freight of about USD 36 a barrel in early October, more than five times the pre-war cost and well over ten times the normal-market figure.

Spills, once a major hazard, have become rare. ITOPF counted about 4,000 tonnes spilled from tankers in 2025, a minute fraction of the roughly 4 billion tonnes of oil shipped each year (calculated from the EIA's 80 million barrels a day). The tile "Tankers, barges and fuel trucks" covers the fleet and the land carriers.

3.3 Gas needs either steel pipes or deep cold

Natural gas is harder to move. At normal pressure a cubic metre of methane holds about 35 MJ, around a thousandth of the energy in a cubic metre of crude oil, so gas must be squeezed or chilled to be moved economically. Smil describes the two answers: high-pressure pipelines over land and liquefied natural gas (LNG) over oceans.

Long-distance gas lines run at about 55 to 85 bar. Friction steadily lowers the pressure, so compressor stations every 65 to 160 km, usually driven by gas turbines burning some of the gas, push it on. Compressors burn roughly 2 to 3% of the gas carried per 1,000 km; across the US system, pipeline and distribution use came to about 3.9% of gas consumption in 2024. Pipelines also give short-term storage: operators let pressure build overnight and draw down this line pack during the day. The bigger concern is leakage. Methane is a far more powerful greenhouse gas than CO2 over a few decades, and the IEA estimates that natural gas operations released about 36 Mt of it in 2025.

LNG is made by cooling gas to about minus 162 C, which shrinks it about 600 times. The refrigeration plant is the expensive and energy-hungry part: it consumes roughly 9 to 15% of the gas's energy. At sea, heat leaking into the tanks boils off 0.07 to 0.15% of the cargo a day, mostly burned as ship fuel. At the importing coast, seawater warms the liquid back into gas, using under 1% of the energy.

LNG has turned gas from a set of regional markets into a global one. The International Gas Union reports 437 million tonnes traded in 2025, up 6.3%, from 524.5 million tonnes a year of liquefaction capacity; the United States was the largest exporter at 110.7 million tonnes. Importers have built about 1,100 million tonnes a year of regasification capacity, more than twice the trade, because spare terminals are a form of security. The "LNG chain" and "Gas pipelines and city gas" tiles cover both routes.

Process flowchart The LNG chain
Inputs Natural gas at the export plant100 units of energy Process steps 1 Treatment and liquefaction

cooled to minus 162 C, shrinking about 600 times; burns about 9 to 15% of the energy

2 LNG carrier

boil-off of 0.07 to 0.15% a day, about 1.4 to 3% over a 20-day voyage, mostly used as ship fuel

3 Regasification

seawater warms the liquid back to gas; under 1% used

Outputs Gas sent into the importer's gridabout 81 to 90 units (calculated)

Ranges from life-cycle inventories and equipment data; actual figures depend on plant design and voyage length.

Source: ifeu (Munter and Liebich), Analysis of the greenhouse gas intensities of LNG imports to Germany (2023), https://www.ifeu.de/fileadmin/uploads/Publikationen/WPKS-Study_Analysis_of_the_greenhouse_gas_intensities_of_LNG_imports_to_Germany.pdf

3.4 Coal moves by the trainload and the shipload

Coal is a heavy solid with about half the energy of oil per tonne and none of its convenience. It cannot be pumped; it must be loaded, unloaded and stockpiled with conveyors, wagons and grabs. Moving it is a business of tonnage. In the United States about 69% of coal for power stations travelled at least partly by rail in 2019, and transport made up about 40% of its delivered cost. China's Daqin line, 653 km from the coalfields of Shanxi to the port of Qinhuangdao, carried 390 million tonnes in 2025, much of it in trains of 20,000 tonnes. In India coal is by far the largest freight on the railways, about 822 million of the 1,615 million tonnes loaded in 2024-25, and the timely arrival of trains at power stations is a constant concern.

At sea, coal moves in bulk carriers of about 82,000 tonnes (Panamax) and 182,000 tonnes (Capesize). World coal trade was about 1.48 billion tonnes in 2025, down about 4% from the 2024 record, as China imported less and Indonesia exported less. Ships flatten the cost of distance: Capesize freight on the benchmark Western Australia to China route, used mainly for iron ore, was about USD 10 a tonne in February 2026. Applied to coal, that is roughly USD 0.2 to 0.25 per MWh per 1,000 km (calculated).

In energy terms, coal transport is cheap: rail and ships use about 1% or less of the coal's energy per 1,000 km, trucks about three times as much. In money terms it is not, because coal is a low-value fuel. A recurring choice is therefore whether to move the coal or the electricity. Many large plants were built at the mine mouth, sending power by wire instead of coal by rail. India's Singrauli coal belt holds NTPC's Singrauli, Rihand and Vindhyachal stations and the 3,960 MW Sasan plant, which runs on coal from its own adjoining mines; Germany's lignite plants sit beside their pits. China does the same over far longer distances with its ultra-high-voltage lines from western coal and wind regions.

Coal transport also has local costs. Dust blows from open wagons, ports handling coal face opposition, and the few slurry pipelines that once carried coal in water needed about a tonne of water per tonne of coal. The "Coal transport" tile and the "Thermal coal" commodity tile cover the trade.

See it in the table

H₂O WaterOil Crude oilGas Natural gasTc Thermal coalFe Iron oreSt SteelOP Oil and product pipelinesTk Tankers, barges and fuel trucksGP Gas pipelines and city gasCT Coal transport

Check your understanding

Roughly what share of the energy in natural gas is used up between the export plant and the importer's grid in the LNG chain?

Liquefaction takes about 9 to 15%, boil-off a few per cent and regasification under 1%, leaving about 81 to 90 units of 100.

Why do oil pipeline owners want long contracts before building?

Tolls mainly repay construction. Throughput spreads that fixed cost, so utilisation decides the unit cost.

What made very large tankers economical, according to Smil?

Longer routes raised the cost per barrel of small ships, so owners built ever larger ones.
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