LISBON, Dec 19 (Reuters) - Portugal's Galp Energia anticipates to start producing biodiesel and biojet fuel from waste in an industrial-scale system it is building at its Sines refinery in 2026, the company, which is mostly 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 lots annually.

It will change waste materials, such as utilized 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 energy.

Galp said in a declaration it received on Wednesday the 3 to process biofuels, which will enable the HVO system to "produce SAF and biodiesel in 2026 ... placing Galp at the leading edge of establishing low-carbon services essential for the energy transition".

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