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 constructing at its Sines refinery in 2026, the business, which is mainly an oil producer and refiner, stated on Thursday.

In 2015 Galp participated in 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 loads per year.

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

Galp said in a declaration it received on Wednesday the 3 reactors to process biofuels, which will permit the HVO system to "produce SAF and biodiesel in 2026 ... placing Galp at the forefront of establishing low-carbon options necessary for the energy shift".

Galp is also 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-