The process plant module, measuring 10 metres by 36 metres, includes the piping and reactors for the biodiesel plant, in which vegetable oil will be processed into biodiesel.
AGC, primarily involved in the oil and gas engineering industry, will build the module at the Australian Marine Complex in Cockburn Sound, south of Perth.
Natural Fuels Australia said the construction of the process module would run concurrently with site works already underway in Darwin, so the module will simply need to be installed upon arrival in Darwin, ready for commissioning.
The Darwin plant has been designed with an initial production capacity of 120,000 tonnes per annum of biodiesel.
Although the plant will initially use palm olein as its feedstock, Natural Fuels Australia said the plant will be able to use other vegetable oils such as canola or soy.