HANOI, Jan 26 -- Fifteen chips companies have expressed interest in investing $8 billion in Vietnam, contingent on the country's commitment to renewable energy, a visiting senior U.S. official said on Friday. Jose Fernandez, undersecretary for economic growth, energy and the environment at the State Department, said those firms had obligations to shareholders so the investment would be conditional on development of a renewables regime in Vietnam. "Right now, as we speak, there are 15 semiconductors companies who have told us they are prepared to invest as much as $8 billion in Vietnam in this industry," he told a press briefing in Hanoi, when asked if U.S. companies wanted to invest in Vietnam. He added, however, that the companies stressed they faced constraints on investing in Vietnam, and in particular they needed the country to develop its regulatory regime for renewable energy. "They made commitments to shareholders and customers they will use only renewable energy," he said, adding that they are waiting for permits and development of the regulatory system in Vietnam before they can go ahead with their investment plans.