The trick is older than it looks. The Fischer-Tropsch process, developed in Germany in the 1920s, gasifies coal and reassembles the gas into liquid hydrocarbons, in effect manufacturing crude oil from a mineral. Sasol scaled it up to a degree no one else ever has. The Secunda complex runs two giant production lines, Sasol II completed in 1980 and Sasol III a few years later, together churning out roughly 160,000 barrels of synthetic fuel a day. Coal goes in by the trainload; petrol, diesel, and a stream of chemicals come out. It is the largest commercial coal-to-liquids operation in the world, an entire petroleum industry compressed onto one Highveld site.

Secunda exists because of isolation. When the oil shocks of the 1970s and the growing embargo against apartheid South Africa threatened to cut off imported crude, the government bet on its one abundant resource: coal. Building the plant was a way to make the country fuel-independent and embargo-proof. A planned town rose alongside it to house the workforce, named Secunda, Latin for second, after the second Sasol plant at its heart. What began as a strategy for survival under sanctions became, decades later, a fixture of the national economy, and a target. During the struggle years the African National Congress attacked the strategically vital plant, events later dramatized in the 2006 film Catch a Fire.

The same chemistry that frees a country from imported oil exacts an enormous price in carbon. Turning solid coal into liquid fuel is profoundly carbon-intensive, and Secunda releases about 56.5 million tonnes of carbon dioxide every year, more than entire industrialized nations such as Portugal. It is, by a wide margin, the largest single point source of greenhouse gas anywhere on Earth. That distinction now hangs over the plant's future. Sasol has partnered with Air Liquide, which took over the site's vast oxygen production, and committed to procuring large amounts of renewable power to begin cutting emissions, a slow turn for a place whose entire reason for being is built on coal.

From the air, Secunda announces itself long before you reach it. Cooling towers and gas flares cluster across the veld, and above them all rises the Sasol III steam plant chimney, a reinforced-concrete stack about 301 meters tall. It is the tallest free-standing structure in sub-Saharan Africa, a spire of pure industry visible for many kilometers across the flat Highveld. There is nothing pretty about it, and that is the point. Secunda is one of those rare landscapes where the abstractions of energy and climate become physically, overwhelmingly real, a place that powers a country and burdens a planet in the same breath.