Public Power Corporation, Greece’s biggest power company, signed an agreement with steel producer Halyvourgiki to form a joint company that will build two power plants with a total capacity of 880 megawatts. Under the terms of the agreement, Halyvourgiki will own 51 percent of the company that will start off with share capital of 10 million euros, PPC said in a bourse filing. The plants, to be built at facilities already being operated by Halyvourgiki, will be powered by natural gas. The deal is subject to approval from competition authorities, added the company. On Wednesday, PPC president Takis Athanassopoulos said the utility is planning to build new power plants and also update its transmission network as part of its 2009-2014 business plan. PPC has earmarked 1.2 billion euros for this year’s investment plans as it takes steps to reduce its dependence on high-cost energy, tapping low-cost fuel sources and increasing the capacity of its plants. PPC, which has a market capitalization of just over 3 billion euros, is planning to invest about 11.5 billion euros under the overall six-year plan. Shares in PPC fell 1.52 percent yesterday to 13 euros. The Athens bourse’s benchmark index slipped 0.86 percent to 1,729.41 points.