ENERGY HUNT; First market test for making gasoline from natural gas

New Zealand's most innovative plan for its offshore natural gas is a $750 million plant, planned for 1985, that would convert the gas into methanol, then into gasoline.

This patented process, developed by Mobil Oil in its US labs, could provide one-third of the country's gasoline while using 16 percent of the natural gas output.

If the project is approved, Mobil will jointly own the refinery with the government, which will own both the natural gas and gasoline. Mobil will also receive a fee from the government for the use of its technology and capital. The company can also charge a "toll" for all the gas it processes. The oil giant will receive about a 10 percent real return on its investment. Once its loans are paid off, Mobil will pay a special windfall-profits tax to the Wellington Treasury.

The plant is controversial in New Zealand, and a final decision has yet to be reached on whether it will go ahead. The Social Credit party opposes it, mainly because of the involvement of a multinational corporation. The Labour Party questions relying on a commercially untried technology. Prime Minister Rober Muldoon of the National Party says there is no question the plant will be built.

Energy Minister Birch says the government is still negotiating with Mobil to nail down the exact cost of the project. In the past year it has escalated from Makeig, Mobil's director of planning, supply, and joint interests, says that unless the project receives "fast track" designation -- fewer bureaucratic delays -- it may never be built. Such a designation can pare at least a year off their construction timetable. Independent sources indicate Mobil is pressing for fast-track approval before the fall election.

Another important consideration is the possibility of a labor shortage among welders, pipelayers, and others workers. Mobil says it will try to avoid any labor bottlenecks by constructing parts of the refinery in various areas of the country.