Hawaii’s leaders have been put on alert that the islands’ small energy marketplace may be in flux with the announcement that a sale of the largest oil refinery is in the works. This means monitoring and contingency planning about the state’s energy infrastructure is in order.

Hawaii still uses imported oil to meet nearly 90 percent of its energy needs, though in recent years policy has changed to drive down that proportion. The Hawaii Clean Energy Initiative, a partnership between the state and the U.S. Department of Energy that was launched in 2008, seeks to generate 40 percent of Hawaii’s energy with its own renewable resources, lowering the use of oil further through energy conservation practices.

It’s not any surprise that this could eventually strain the system of local oil supplies, specifically the fuel production and sales by the state’s two refineries, Chevron Corp. and Tesoro Corp.

Tesoro announced on Tuesday its plans to sell its Hawaii operations, comprising the larger of the two refineries, a chain of 32 gas stations, 20 of them with attached convenience stores.

Tesoro did not disclose in its announcement its reasons for divesting, beyond the inconclusive statement, "Our business in Hawaii does not align with our strategic focus."

However, company executive Lynn Westfall said in March 2010 that the Hawaii operations the previous year was a loss, due in part to the market’s small size and low growth prospects.

The sale of Tesoro’s Hawaii assets is not due to happen until mid-year, but state officials are already on alert that this could be a disruptive event. Under state laws that aim to keep trade as open as possible, the state Office of the Attorney General could bring court actions to prevent a sale that may lessen competition or "tend to create a monopoly in any line of commerce."

It’s clear that this office must monitor the situation carefully. The transaction could all go smoothly: This is not the first time this refinery has changed hands, most recently in 1998 from Pacific Resources International. Hawaii could resume business with two refineries competing for fuel sales.

Chevron executives are noncommittal about its own interest in purchasing the assets. But that would produce a monopoly, a single company producing the fuel the state needs, clearly not in consumers’ best interest.

But if the state is serious about its clean-energy timetable — and it should be — the market will reach a point at which demand for oil is too low to support competing refineries. Competition will then need to come from alternative energy sources giving consumers a choice.

Hawaii is not prepared for that. Thanks to the Pentagon, which is concerned about energy security worldwide, the military has been increasing purchases of biofuels and is testing ways to use more of them in surface ships and aircraft.

But the civilian sector needs alternatives to petroleum fuels, too. The advent of electric vehicles is promising, but the electrical grid can’t yet yield the energy that a wholesale conversion to EV cars would require. Liquid fuels will be needed. Biofuel production — using locally produced feedstock — must be ramped up. Storage and delivery systems for these fuels must be developed to prepare Hawaii for a rebalanced energy portfolio.

Various government and private experts who have tracked Hawaii’s energy plans agree that tectonic shifts have long been expected. For example, the U.S. DOE funded a demonstration project on the Tesoro site to explore the possibility of converting one of the refineries to biofuel. That concept deserves further exploration.

Hawaii’s need to become more self-sufficient in energy is as critical as ever; the state must stay the course.

If anything, the Tesoro shakeup underscores just how vulnerable the public is to an industry over which it has no control.

But it’s also evident that the transition won’t be easy. The impending sale serves as a wakeup call: Industry and government need to pursue fallback options to help Hawaii through what may be rough patches in the years ahead.