LISBON, Dec 19 (Reuters) - Portugal's Galp Energia anticipates 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 mostly an oil producer and refiner, said on Thursday.

In 2015 Galp got in into 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, likewise called sustainable air travel fuel (SAF), using produced by an electrolyser powered by wind or solar energy.

Galp stated in a statement it got on Wednesday the three reactors to process biofuels, which will enable the HVO unit to "produce SAF and biodiesel in 2026 ... placing Galp at the leading edge of developing low-carbon options essential 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