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 company, which is primarily an oil and refiner, said on Thursday.

In 2015 Galp entered into a 75%-25% joint endeavor 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 sustainable biodiesel and biojet fuel, likewise known as sustainable aviation fuel (SAF), utilizing green hydrogen produced by an electrolyser powered by wind or solar power.

Galp said in a statement it got on Wednesday the three reactors to process biofuels, which will allow the HVO unit to "produce SAF and biodiesel in 2026 ... positioning Galp at the leading edge of establishing low-carbon services vital 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