India"s third largest refiner Bharat Petroleum Corp Ltd (BPCL.NS) said on Monday it has tied up with the country"s nuclear research institute for an electrolyser technology for green hydrogen as it seeks to achieve net zero emissions by 2040. India, the world"s third biggest greenhouse gas emitter, is aiming to reach net zero emissions by 2070 and wants to raise the share of renewables in its energy mix to 50% by 2030 from 38% currently. BPCL"s Chairman A. K. Singh said the refiner plans to scale up indigenous alkaline electrolyser technology for use in refineries via collaboration with the Bhabha Atomic Research Centre. An electrolyser splits water into hydrogen and oxygen using electricity. For green hydrogen, renewable energy is used for electrolysis. At present Indian companies import electrolyser plants. India"s draft National Hydrogen Mission mandates that refiners and fertiliser producers should meet half of their hydrogen needs through green hydrogen by 2030. The federal government has provided financial support for setting up electrolysers in India. read more Companies, including Reliance Industries (RELI.NS), Adani Group, Indian Oil Corp (IOC.NS), NTPC (NTPC.NS) and GAIL (GAIL.NS) have announced plans to play a critical role in India"s green hydrogen roadmap. read more Refineries use large quantities of hydrogen for de-sulfurisation to make petrol, diesel and other chemicals. Singh said BPCL aims to offset emissions from its crude refining and energy it uses by 2040, otherwise called Scope 1 and 2 emissions. The company has not yet decided on timeline to reduce emissions linked to the use of refined products such as gasoline sold at a fuel stations or jet fuel sold to airlines. BPCL plans to expand its renewable energy portfolio and would use green energy for its energy needs and expansion projects, Singh said. Reporting by Nidhi Verma. Editing by Jane Merriman Our Standards: The Thomson Reuters Trust Principles.