LISBON, Dec 19 (Reuters) - Portugal's Galp Energia expects to begin 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 primarily an oil manufacturer and refiner, said on Thursday.

Last year Galp entered into a 75%-25% joint endeavor with 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 products, such as utilized cooking oils, into eco-friendly biodiesel and biojet fuel, also referred to as sustainable air travel 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 3 reactors to process biofuels, which will enable the HVO unit 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 likewise investing 250 million euros in a 100 megawatt (MW) electrolyser unit to produce green hydrogen to power the refinery in Sines. ($1 = 0.9637 euros) (Reporting by Sergio Goncalves