ATHENS (Reuters) – Greek electricity utility Public Power Corp. (PPC) said on Thursday it had agreed to buy the renewable energy portfolio of Volterra, a fully-owned unit of construction group Avax. PPC said the value of the deal corresponds to an enterprise value of 133 million euros ($141.72 million) and is subject to regulatory approvals. “PPC Renewables gets a significant portfolio of renewable energy sources of more than 110 Megawatts, which helps increase its own portfolio and its differentiation through the addition of wind parks,” a PPC official said, declining to be named. Volterra’s …