Two public sector giants--Indian Oil Corporation (IOC) and National Thermal Power Corporation (NTPC)--have signed a memorandum of understanding to set up petro-fuel power plants in the country. The MoU was signed by IOC chairman M A Pathan and NTPC chairman and managing director CP Jain here yesterday, an official press release said. IOC and NTPC would form a joint venture to set up petro-fuel based power plants, utilizing refinery residue or other petroleum products as fuel, on the basis of feasibility studies to be carried out.