A Gas Contract Broke, the World's Biggest Alumina Refinery Halved Output, and a Regulator Fixed It in Three Days

On August 11, 2026, Norsk Hydro said its Alunorte refinery in the northern Brazilian state of Pará would temporarily cut alumina production to 50% of capacity. The cause was not a fire, a strike or a fault in the plant. Its gas supplier, CELBA, had notified it of disruptions to natural gas availability, and Alunorte reduced output to match the gas it could actually get.

Two days later the situation had substantially reversed, and the mechanism that reversed it is the interesting part.

Why a refinery is hostage to a gas contract

Alumina is the intermediate product between bauxite ore and aluminium metal: bauxite is refined into alumina, and alumina is smelted into aluminium. Alunorte performs the first step, at a nameplate capacity of 6.3 million tonnes a year, which makes it one of the largest facilities of its kind anywhere.

That refining step needs enormous quantities of heat, and the heat comes from burning natural gas. There is no meaningful buffer — a refinery cannot store weeks of gas the way it can stockpile ore. If the gas arriving through the pipe drops, throughput drops with it, more or less immediately and more or less proportionally. Cutting to 50% was not a commercial decision about demand. It was an arithmetic consequence of the fuel available.

The three responses

Norsk Hydro listed its contingency measures, and they are worth reading as three different time horizons for the same problem:

The second measure is the one that mattered. Barcarena is an LNG receiving and regasification terminal — the facility where liquefied natural gas arrives by ship, is turned back into gas, and is fed into the local network. Alunorte was buying its gas from CELBA rather than importing it. Getting direct terminal access would mean sourcing gas itself instead of depending on an intermediary whose own supply had just failed.

What the regulator changed

Brazil's oil, natural gas and biofuels regulator, ANP, approved Alunorte to become a self-importer of gas. With that approval in hand, Alunorte reached a temporary agreement with CELBA covering terminal access, and alumina production began ramping back toward full capacity.

Note the sequence, because it is not the obvious one. The regulatory approval did not itself deliver a single molecule of gas. What it did was change Alunorte's position: a plant that can lawfully import for itself is negotiating with its supplier from a different place than a plant that cannot. The temporary agreement followed the approval, and the restart followed the agreement. A permission changed a commercial outcome.

The bill

Norsk Hydro attributes the financial impact to two distinct things, and separating them explains why the number is as large as it is. The first is the lost production — tonnes that were never made and cannot be sold. The second is that the company was buying gas at prices above the contract price, so the alumina it did produce during the period cost more per tonne than it should have.

A disruption of this kind therefore hurts twice: less output, and worse economics on the output that survives. Against 6.3 million tonnes of annual capacity, roughly 110,000 tonnes is a small fraction of a year. The associated impact is still up to $100 million, because the price paid for fuel applied to everything running, not only to the part that stopped.

The company describes the CELBA agreement as temporary and says it continues to pursue long-term solutions. The restart is real; the underlying dependency has been worked around rather than removed.