Altona’s Mobil refinery is set to get a giant tank, matching Australia’s largest crude oil tank at Geelong.

Owner ExxonMobil Australia on Friday announced the $50 million project, which is its biggest investment at Altona since 2005.

The new tank will hold 100 million litres – the equivalent of 40 Olympic swimming pools – and will be built within the existing refinery footprint.

Standing 20 metres high, the tank’s diameter will be 78 metres – wider than an international soccer pitch.

Numerous homes sit about a kilometre from the refinery, whose southern boundary is Kororoit Creek flowing into Port Phillip Bay.

The new tank will increase the refinery’s storage capacity by almost half, from 220 million to 320 million litres.

Mobil’s Australia and New Zealand refining manager Riccardo Cavallo said the new storage facility was needed to help meet a growing demand for transportation fuels.

“During the past five years, ExxonMobil has invested more than $400million at the Altona refinery and Yarraville terminal,” he said.

“Recent investments include construction of a three-kilometre pipeline connecting Yarraville terminal to the Somerton jet fuel pipeline, construction of two new fuel storage tanks at Yarraville terminal and work to increase Altona refinery’s production.”

The Altona refinery supplies half of Victoria’s fuel. It processes up to 13 million litres of crude oil a day into petrol, diesel, aviation fuel and LPG.

The building phase is expected to create 100 jobs.

Construction will start this month and is scheduled for completion in the first quarter of 2020. Rival Viva Energy last November opened its 100 million litre tank at Geelong.