LISBON, Dec 19 (Reuters) - Portugal's Galp Energia expects to begin 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 mostly an oil producer and refiner, said on Thursday.

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

It will transform waste materials, such as used cooking oils, into sustainable biodiesel and biojet fuel, also called sustainable air travel fuel (SAF), utilizing green hydrogen produced by an electrolyser powered by wind or solar power.

Galp said in a declaration it got on Wednesday the 3 reactors to process biofuels, which will enable the HVO unit to "produce SAF and biodiesel in 2026 ... placing Galp at the forefront of establishing low-carbon services important 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-