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

Last year 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 heaps annually.

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

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

Galp is also 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-