The situation in the world oil market changed completely after the two oil crises in 1973 and 1979.

The oil producing countries - united in OPEC - decided to raise the price of crude oil drastically. At one point, the price of a barrel of oil was ten times the prevailing price in the previous decades. This led to a severe economic recession. Energy savings became the priority, to the detriment of growth, and naturally the demand for oil fell. The net result was overcapacity. The oil crisis also led to a serious miscalculation. After the 1973 price explosion, it was generally assumed that prices for crude oil and refined products would remain high or go even higher. The opposite happened. As a result of energy savings and overcapacity, prices began to drop.

In this period during the early 1970s, Esso completely modernized the Antwerp industrial complex. A brand new refinery was added to the existing structure, including large units for atmospheric and vacuum distillation, a sulfur removal plant and several other plants. But the initial plans were modified, even during construction. The Catalytic Cracker or CatCracker, which was to be demolished, was retained because the added value of converted light oil products had increased considerably as a direct consequence of the oil crisis.

In the 1980s, the oil industry - and Esso was no exception - reacted to the new circumstances with measures to dramatically raise productivity, including reorganization, restructuring, scaling-up, modernization and automation. The sales and distribution network was rationalized. The number of depots and service stations was drastically reduced, while sales volumes per outlet were significantly increased.

Within this context, Esso Benelux was created in the mid-1980s as a close joint venture between Esso Belgium, Esso Nederland (Netherlands) and Esso Luxembourg. The Esso refinery in Rotterdam, built at the peak of the economic boom, was rebuilt at a cost of over 2.5 billion guilders (1.2 billion euros). The main focus was on depth conversion, which is the conversion of less economically attractive heavy oil fractions to more valuable, lighter products. The upgraded conversion refinery no longer produced any heavy fuel oil at all, after the new FLEXICOKER (an Exxon patent) had been constructed. This thermal cracker installation converts the heaviest hydrocarbon molecules in the crude oil into lighter ones. Many new plants were constructed at the same time as the FLEXICOKER, resulting in an entirely new industrial complex. In 1994, further investment was made with the construction of the HydroCracker, a desulfuring annex conversion unit.

The Antwerp refinery also concentrated increasingly on products with a high added value. It became the largest European producer of solvents, a product introduced to the market by Exxon Mobil Chemical. Further investment followed, including an alkylation plant, a production unit for higher olefins and a complete combined heat and power plant, like the one in Rotterdam, that generates roughly as much power as the refinery requires for itself.