Biofuel for Hawaii

Sustainable biofuels could provide Hawaii with enough fuel, food and fiber to significantly reduce it’s dependence on foreign sources of fossil fuel and imported food.

Biofuel plantations could revitalize Hawaii’s agricultural sector, anchoring a cluster of farm businesses and providing hundreds of jobs where the rural populations live. Locally produced biofuels can help Hawaii meet it’s carbon reduction goals with sustainable land use and farming.

Myths surrounding biofuels have created false conflicts of food vs. fuel, imports vs. local production and carbon negative vs. carbon positive lifecycles.

A host of problems can be created by any agricultural enterprise (including for the food we eat) developed on the wrong lands, using the wrong crop, with monoculture farming methods, outdated processing and unfair labor practices. None of the companies in Hawaii that are serious about biofuels plan to engage in these practices.

Locally produced biofuels could meet Hawaii’s Renewable Fuels Standard targets of 10 percent ethanol by 2015, supply 70 percent transportation needs by 2025, and enable utilities to exceed the Renewable Portfolio Standard by providing biomass to power.

How much biofuel the state needs depends on whether it adopts energy-efficient transportation practices, from mass transit to electric vehicles. If it does nothing, gasoline demand will increase from 475 million gallons per year today to well over 525 million gallons per year by 2025. If it gets serious about transportation efficiency, it could reduce demand below 300 million gallons per year by 2025.

Ethanol has a lower energy content than gasoline, partially offset by higher combustion efficiency, so there would need to be 265 million gallons of ethanol production to meet the Hawaii Clean Energy Initiative’s 70 percent energy independence goal. At the moment 130 million gallons per year of diesel is used for land and marine transportation, so there would need to be 95 million gallons of biofuel production to meet the HCEI 70 percent goal.

By applying biotechnology and agricultural know-how to better crop selection, biofuels can do better than traditional Hawaii crops like sugar, even without resorting to GMO techniques.

Today, Brazil grows the best canes for energy, which double the potential energy yield of traditional cane, yielding about 8 tons of sugar and 26 dry tons of fiber per acre. University of Hawaii researchers’ field trials of high-yield tropical grasses such as banana grass produce 22 dry tons of fiber per acre. Australian yields of eucalyptus can reach 14 dry tons per acre.

For biodiesel, oil crops such as jatropha can yield one metric ton of oil per acre and oil palms can yield two to four metric tons of oil per acre (one metric ton of oil = 300 gallons of biodiesel).

These yields are being achieved today. Other crops being researched globally β€” such as sorghum, leauceana and miscanthus β€” can provide even better fiber yields while requiring lower amounts of water and fertilizer.

Even better, algae has the biological potential to yield 10 times the oil of land plants, nearly 33 tons per acre. Algae technology holds tremendous promise, but is five to 10 years from commercialization.

How much fuel we get from biomass also depends on the conversion technology. High yielding grasses, coupled with cellulosic technologies that convert the woody part of the plants into fuels or chemicals, could yield from 2,400 to 2,600 gallons per acre, more than doubling traditional ethanol production. For tree crops, that could be 1,400 gallons per acre.

On the horizon are even more advanced cellulosic conversion methods that could yield 110 to 140 gallons per dry ton of biomass. Existing experimental algae ponds might produce only 1,000 to 2,000 gallons per acre, but the potential is as high as 9,000 to 10,000 gallons per acre.

Is there enough arable land in Hawaii to meet the states fuel needs without affecting existing diversified agriculture? Of the 675,000 acres of prime agricultural land in Hawaii, fewer than 200,000 acres are being used, so the answer would seem to be yes, but the inputs required to maintain the infrastructure would have to be grown locally and so that land would have to be accounted for.

Using advanced technologies, 50,000 acres in high-yield fiber crops to produce about 130 million gallons of ethanol; 100,000 acres in high-yield forestry crops to produce 140 million gallons of ethanol and 10,000 acres of algae ponds to produce 95 million gallons of biodiesel (or jet fuel).

Algae ponds do not require prime or forest land; they are most economic when placed near CO2 sources such as power plants, which would also reduce concern about traffic on our already congested highways.

The industrial symbiosis approach copies nature; nothing is wasted. Using biology and byproducts, there is a natural symbiotic relationship between biofuels and animal husbandry. An enlightened approach to growing high-yield fiber crops is to periodically rotate these crops with legumes to fix nitrogen. The seed meal can be used for animal feed and the plant oil can be used for biodiesel feedstock.

For Hawaii’s agricultural lands, if the current use is forest replaced with biofuel tree crops, the net carbon balance is likely to be neutral for soil carbon. The same is true for pasture conversion to grasses and the overall system will be carbon negative, since we are substituting for fossil fuels. If grasslands are converted to tree crops, more carbon is sequestered in the soil.

Just as natural systems evolve, biofuels will evolve as well.

Image of coffee plantation on Kauai by msprague on flickr under the Creative Commons license