Power company Dynegy said that it would buy coal and gas power plants for $6.25 billion to increase its presence in two less regulated eastern US markets, sending its shares up as much as 22.5 per cent.The deals for select assets of Duke Energy Corp and Energy Capital Partners will nearly double Dynegy's national generating capacity and allow the company to retail electricity in Illinois, Ohio, Pennsylvania and Michigan, increasing its exposure to the PJM and New England markets. The acquisitions are the latest in a series of deals aimed at minimising exposure to the volatile wholesale power market, and analysts expect consolidation to continue. Earlier this year, Wisconsin Energy Corp said it would buy Integrys Energy Group for $5.71 billion about two months after Exelon Corp agreed to buy Pepco Holdings for $6.83 billion to cut exposure to the wholesale power market. "The structure of the PJM (Pennsylvania, New Jersey, Maryland) marketplace is more transparent and probably, in the long term, more beneficial to (power) generators," ISI Group analyst Jon Cohen said. Dynegy emerged from bankruptcy in 2012, less than a year after its unit filed for protection from creditors, burdened by costly power plant leases.The company said it intends to issue about $5 billion in new unsecured bonds and $1.25 billion in equity and equity-linked securities to fund the deals. At the end of June, Dynegy had long-term debt of about $1.97 billion. Chief executive Robert Flexon expects the deals to triple the company's 2015 adjusted EBITDA and add to free cash flow per share in 2015 and beyond.