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 constructing at its Sines refinery in 2026, the company, which is mostly 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 Vegetable Oil (HVO) plant, which will have a production capability of 270,000 metric lots per year.

It will change waste materials, such as utilized cooking oils, into renewable biodiesel and biojet fuel, likewise referred to as sustainable aviation fuel (SAF), utilizing green hydrogen produced by an electrolyser powered by wind or solar energy.

Galp stated in a declaration it received on Wednesday the three reactors to process biofuels, which will allow the HVO system to "produce SAF and biodiesel in 2026 ... putting Galp at the leading edge of developing low-carbon solutions important for the energy shift".

Galp is also investing 250 million euros in a 100 megawatt (MW) system to produce green hydrogen to power the refinery in Sines. ($1 = 0.9637 euros) (Reporting by Sergio Goncalves