LISBON, Dec 19 (Reuters) - Portugal's Galp Energia expects to start producing biodiesel and biojet fuel from waste in an industrial-scale system it is developing at its Sines refinery in 2026, the business, which is mainly an oil manufacturer 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 per year.

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

Galp said in a declaration it received on Wednesday the three reactors to process biofuels, which will enable the HVO unit to "produce SAF and biodiesel in 2026 ... positioning Galp at the leading edge of developing low-carbon services important 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-