Gridco signed the PPAs with Orissa Hydro-Power Corporation and Orissa Thermal Power Corporation Limited.
Besides, Gridco, the state`s lone bulk power supplier agency, also executed PPAs with seven developers of Biomass Power Plants which would generate 93 MW under the renewable energy category.
"The two projects of OHPC and OTPCL being exclusively in the state sector, will enhance the energy security of Orissa," Energy Minister Atanu S Nayak, who was present during the signing of the PPAs, said.
OHPC is setting up three hydro-power units -- Sindol-I, II and III at Deogaon in Sambalpur district (96 MW), Kapasira in Sonepur district (96 MW) and Godhaneswar in Sonepur district (130 MW).
Together, the three units would have installed capacity of 322 MW of hydro-power while the proposed design energy capacity could touch 1085 MW.
The project would help to restore the hydro-thermal mix of power sector in the state, Energy Secretary Pradip Kumar Jena said.
Since hydro-power was low cost power, it would help keep the retail tariff at a reasonable level in future, he said.
OTPCL, a joint venture of OHPC and Orissa Mining Corporation (OMC) would generate 2000 MW of thermal power.
"The two companies have committed their allocated coal blocks to this thermal power generation project in joint venture," the minister said.
OTPCL would use super critical technology and adopt the best environment friendly technology in the project, Nayak said.
The project would also have scope for further expansion from its present installed capacity of 2,000 MW.
The Gridco last week also signed PPA with NTPC for transmission of about 2800 MW in the eastern region.