LISBON, Dec 19 (Reuters) - Portugal's Galp Energia expects to start producing biodiesel and biojet fuel from waste in an industrial-scale unit it is developing at its Sines refinery in 2026, the business, which is mainly an oil manufacturer and refiner, said on Thursday.

In 2015 Galp entered into a 75%-25% joint venture with Japan's Mitsui to invest 400 million euros ($415 million) in the Hydrogenated Grease (HVO) plant, which will have a production capability of 270,000 metric tons per year.

It will change waste materials, such as utilized cooking oils, into sustainable biodiesel and biojet fuel, likewise understood as sustainable air travel fuel (SAF), using green hydrogen produced by an electrolyser powered by wind or solar power.

Galp said in a statement it received on Wednesday the three reactors to process biofuels, which will enable the HVO system to "produce SAF and biodiesel in 2026 ... placing Galp at the forefront of establishing low-carbon solutions essential for the energy shift".

Galp is likewise investing 250 million euros in a 100 megawatt (MW) electrolyser unit to produce green hydrogen to power the refinery in Sines. ($1 = 0.9637 euros) (Reporting by Sergio Goncalves;-RRB-