Canadian energy company InterOil Corp. said it expects to build a Papua New Guinea liquefied natural gas venture at less than half the cost of a rival project. InterOil estimates its LNG development will cost between $5 billion and $7 billion US, compared with a $15-billion US spending bill for the Exxon Mobil Corp.-led venture in Papua New Guinea, said Wayne Andrews, InterOil's vice-president of capital markets. The two ventures are among more than a dozen in Australia and the South Pacific nation seeking to meet Asian demand for cleaner-burning fuels.