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

Last year Galp entered into a 75%-25% joint endeavor with Japan's Mitsui to invest 400 million euros ($415 million) in the Hydrogenated Grease (HVO) plant, which will have a production capacity of 270,000 metric loads each year.

It will transform waste materials, such as used cooking oils, into eco-friendly biodiesel and biojet fuel, also understood as sustainable aviation fuel (SAF), using green hydrogen produced by an electrolyser powered by wind or solar energy.

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

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