LISBON, Dec 19 (Reuters) - Portugal's Galp Energia expects to begin producing biodiesel and biojet fuel from waste in an industrial-scale unit it is constructing at its Sines refinery in 2026, the business, which is primarily an oil manufacturer and refiner, stated 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 Vegetable Oil (HVO) plant, which will have a production capability of 270,000 metric tons each year.

It will transform waste products, such as utilized cooking oils, into renewable biodiesel and biojet fuel, also called sustainable air travel fuel (SAF), using green hydrogen produced by an electrolyser powered by wind or solar energy.

Galp stated in a statement it on Wednesday the three reactors to process biofuels, which will permit the HVO unit to "produce SAF and biodiesel in 2026 ... putting Galp at the forefront of developing low-carbon options necessary for the energy shift".

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