Hawaiian Electric Co. engineers knew they were venturing into the unknown when company executives tasked them with finding out whether one of the utility’s 40-year-old petroleum-fired steam generating units could run on crude palm oil.

For years the tropical vegetable oil has been used primarily as an ingredient in a variety of consumer goods like snack foods, soaps and cosmetics. It’s what makes the center of an Oreo cookie creamy and a Cheez-It cracker crispy.

As a fuel source, palm oil didn’t receive any serious consideration until a few years ago when Malaysia began refining it into a biofuel, which the country’s oil companies blend with petroleum-based diesel for use in automobiles.

But generating electricity using crude palm oil? "As far as we knew, no one had ever fired a steam turbine using 100 percent crude vegetable oil," said Ron Cox, HECO’s vice president for generation and fuels.

HECO launched the project last year at the Kahe Power Plant as part of an experiment to see how various alternative fuels will work in its group of oil-fired boilers. HECO has pledged to have alternative energy make up 40 percent of its electricity production by 2030.

Although the 1.6 million gallons of palm oil used in the test was imported from Malaysia, HECO officials say their goal is to use locally produced biofuels in the future. Palm oil was selected for the initial test because it was readily available in sufficient quantities at a price competitive with petroleum-based fuels, HECO said.

Palm oil was priced at a slight premium to crude oil when HECO started planning the Kahe biofuel test about 2 1/2 years ago, said David McDermott, an operations and maintenance engineer at the Kahe plant. Since then, however, the spread has widened with Malaysian palm oil now trading for nearly $180 a barrel compared with about $90 a barrel for crude oil futures on the New York Mercantile Exchange.

Not only has the price made palm oil less attractive, but critics of HECO’s biofuel strategy say the whole effort is misguided. Local groups promoting energy independence and environmental sustainability argue that by including biofuels in its plan, HECO will end up diverting resources and energy away from wind, solar and ocean technologies that they say are better suited for power generation. The best use of biofuels is in the transportation sector because aircraft and automobiles can fill their tanks with biofuel but they can’t be powered directly with wind, solar and ocean energy, they say.

Nonetheless, HECO officials contend the company’s plan will play a key role in helping jump-start a local biofuel industry because investors won’t pour money into biofuel production until they have the assurance that there is a large potential customer for the product, such as a utility. Also, HECO says by retrofitting its existing generation equipment to run on biofuels, the utility can continue to make use of its $6 billion in capital investment without significant additional spending.

The basic goal of the Kahe test was to see how much palm oil could be substituted for the low-sulfur fuel oil normally burned at the plant and still have the plant function normally. HECO started with a mix of about 20 percent palm oil in one of the plant’s six generating units and gradually increased the ratio with no ill effects until the unit was burning 100 percent palm oil last month.

HECO officials said they weren’t sure what to expect. While there was plenty of information available on the performance of palm oil as a food additive, there was virtually no data available to HECO engineers on the oil’s energy content, combustion temperature and other specifications.

Plant superintendent Teddy Canterbury said he was fairly confident going into the test that the unit could operate on 100 percent palm oil. "What surprised me is that we were able to run the unit at 100 percent of its capacity," he said.

The 90-megawatt generator where the test was conducted is one of six generating units at the Kahe plant, which is HECO’s largest with 650 megawatts of capacity. HECO received approval from the Public Utilities Commission to spend $4.7 million on new equipment for the test at the "Kahe 3" generator, which it said will help it form a base line as it experiments with other biofuels.

The equipment included new pumps, motors, valves, filters and a mixing station to blend the palm oil with the low-sulfur fuel oil. Engineers essentially built a parallel system that would allow palm oil to be fed into the boiler at Kahe 3 without any cross-contamination. The design also needed to be done in such a way that if the palm oil fuel line needed to be shut down, the plant operators could switch back to 100 percent low-sulfur fuel oil without disrupting electrical generation, said McDermott, the Kahe engineer.

One of the first things they noticed when they began adding palm oil to the fuel mix was the color of the flames shooting out of the burner tips in the boiler, which changed from a reddish to a blue-green hue, McDermott said. The shift was a sign that the palm oil produced a cleaner-burning flame than the low-sulfur fuel oil. That observation was confirmed by later tests that showed that visible emissions, as well as emissions of nitrogen oxides and sulfur dioxides, were lower with the palm oil, he said.

Another difference between the two fuels was that it took about 10 percent more palm oil to achieve the same level of power generation. To heat the boiler to the range of 2,400 degrees to 2,600 degrees needed to produce 90 megawatts of power, plant operators had to pump in 107 gallons of palm oil per minute compared with 96 gallons per minute of low-sulfur fuel oil, McDermott said.

All the testing was done under the supervision of the Electric Power Research Institute, a nonprofit industry group that works to develop best practices for electrical utilities.

Henry Curtis, director of the environmental group Life of the Land, said HECO’s biofuel program is flawed on several levels.

"The No. 1 use of biofuels should be in our air fleet, followed by ground transportation, with electricity production last. It shouldn’t be the other way around," Curtis said. "We need to put our resources where they can be used best."

He also cited the environmental damage caused by palm oil plantations in some parts of the world. The destruction of rain forests in Indonesia to make way for plantations has put further pressure on endangered species like the orangutan and Sumatran tiger.

HECO noted that the palm oil it buys comes from Malaysian-based Sime Darby, which produces the product under the sustainability standards laid out by the Natural Resources Defense Council.

Curtis said although Malaysia is "somewhat better" than Indonesia in its palm oil production methods, there are ways that companies can game the system when it comes to securing sustainability certifications.

Jeff Mikulina, executive director of the Blue Planet Foundation, said he would like to see HECO focus its efforts on other initiatives, like building a smart grid that would allow the utility to take greater amounts of electricity generated by rooftop photovoltaic systems.

Mikulina said he was concerned that if HECO locked itself into using biofuels for electricity production, it would be closing off the alternative fuel for more productive uses, such as transportation.