Sustainable biofuels have the potential to provide Hawaii with enough fuel, food, and fiber to make a significant impact on reducing our dependence on foreign sources of fossil fuel and imported food. Biofuels plantations can revitalize Hawaii’s agricultural sector, creating the anchor for a cluster of agricultural business and providing hundreds of jobs close to where our rural populations live.
Locally produced biofuels can help the state meet its carbon goals, when sustainable land use and farming practices are employed. To achieve this promise, we will need to take a whole systems approach to biofuels, deploying advanced agricultural practices and capitalizing on the linkages between biofuels and agricultural to utilize the entire plant and all the byproducts, creating a 21st Century ecosystem based on industrial symbiosis.
There are many myths surrounding biofuels that have created controversies based on false dichotomies between food vs. fuel, imports vs. local production, and carbon negative vs. carbon positive lifecycles. To be sure, if biofuels plantations (or any agricultural commodities, including the food you eat) are developed on the wrong lands, using the wrong crop, with monoculture farming methods, millennia-old processing technology, and unfair labor practices, this will create the host of problems that the critics are concerned about. None of the companies in Hawaii that are serious about biofuels, either as producers or consumers, are planning to engage in these practices.
Locally produced biofuels could meet the State’s Renewable Fuels Standard targets of 10% ethanol by 2015, supply 70% transportation needs by 2025, and enable our utilities to exceed the Renewable Portfolio Standard by providing biomass to power. How much biofuel we need depends on whether we adopt energy efficient transportation policies and vehicles. If we do nothing, our gasoline demand will increase from 475 million gallons per year today to well over 525 million gallons by 2025.
If we get serious about transportation efficiency, we could reduce demand below 300 million gallons per year by 2025. Since ethanol has a lower energy content than gasoline, which is partially offset by higher combustion efficiency, we would need 265 million gallons of ethanol production to meet the Hawaii Clean Energy Initiative’s 70% energy independence goal. For diesel, we use ~70 million gallons for land transportation and another 65 million gallons for marine transportation, or 130 millions in total. Therefore, we would need 95 million gallons to meet the HCEI 70% goal. How far can we go on the available land and water in Hawaii without compromising our other agricultural goals?
It all begins with the biomass productivity per acre. Biomass productivity is based on the yield of the crop, which is measured initially in wet tons harvested from the field, but then usually converted into dry tons, which is amount of biomass that can be used for energy, once the water has been removed. For example, in the traditional sugar cane that is grown on Maui today yields ~50 wet tons per acre, which translates into ~6 tons of sugar, and ~ 9 dry tons of fiber per acre. Typical fuel wood plantations, such as conventional eucalyptus achieve ~9 dry tons of fiber per acre. We can do a lot better applying our biotechnology and agricultural know-how to better crop selection, even without resorting to GMO techniques.
Today, Brazil grows the best canes selected for energy use, which double the potential energy yield of traditional cane, yielding ~ 8 tons of sugar and ~26 dry tons of fiber. UH researchers have done field trials of high yielding tropical grasses such as banagrass that yields ~22 dry tons of fiber per acre. Australian yields of eucalyptus can reach ~14 dry tons per acre. For biodiesel, oil yield crops such as jatropha can yield 1 metric ton of oil per acre and oil palms can yield 2-4 metric tons of oil per acre (one metric ton of oil equals ~ 300 gallons of biodiesel). These are being achieved today. There are other crops that are being researched globally, such as sorghum, leauceana, and miscanthus that can provide even better fiber yields with lower water and fertilizer inputs.
And then, there is algae. Algae has the biological potential to yield ten times as much as terrestrial plants, nearly ~ 33 tons of oil per acre! Algae technology holds tremendous promise, but is five to ten years from commercialization. The good news is that two leading companies, Hawaii Bioenergy and Hawaii BioPetroleum, have both announced algae research projects that will be demonstrated in Hawaii, starting next year.
How much fuel we get from the biomass depends on what conversion technology we use. Traditional sugar based ethanol to energy systems using fermentation and cogeneration produce approximately 1,000 gallons of ethanol and 5 MWh of power per acre. Traditional oil palm yields ~ 600 gallons of biodiesel per acre. Second generation cellulosic technologies are targeting 70 to 100 gallons per dry ton of biomass, whether via biological enzymatic fermentation or gasification to syngas, which then can be synthesized into fuels.
Thus, advanced grasses coupled with advanced technology can yield ~2,400-2,600 gallons per acre, more than doubling traditional ethanol production. For tree crops, we could envision 1,400 gallons per acre. On the horizon, there are even more advanced cellulosic conversion methods that could yield 110-140 gallons per dry ton. Existing algae experimental ponds may only produce 1-2,000 gallons per acre today, but the potential is 9-10,000 gallons per acre.
Do we have enough arable land in Hawaii to meet our fuel needs without impacting the diversified agriculture already in place? Certainly do. Using advanced technologies, we would need 50,000 acres in high yielding fiber crops producing ~130 million gallons of ethanol, 100,000 acres in high yield forestry crops producing ~140 million gallons of ethanol, and 10,000 acres of algae ponds producing ~ 95 million gallons of biodiesel (or jet fuel). We are currently using near 48,000 acres in the state to produce traditional sugar cane on Maui and Kaui. Of the 675,000 acres of prime agricultural land, only 200,000 acres are currently being utilized (including the current sugar production). We have even more acres of potential forest lands. Algae ponds do not require prime agricultural and forest lands, and are more economic when placed near CO2 sources such as power plants. If production systems and bio-refineries are co-located on the large tracts of still available land, then concerns regarding transportation logistics on our already congested highways are largely addressed.
How do biofuels plantations help address Hawaii’s food needs? The industrial symbiosis approach recognizes that, in nature, nothing is wasted. Thus, using biology and byproducts, there is natural symbiotic relationship between the biofuels sector and animal husbandry. A more enlightened approach to growing high yielding fiber crops is to periodically rotate these crops with legumes to fix nitrogen, where the seed meal can either be used for animal feed, and the plant oil can be used for biodiesel feedstock. The byproduct of biodiesel production is glycerin, which is used as a cattle feed to help fatten the animals before slaughter, which can avoid the shipment of cattle to the mainland for finishing. When algae become viable, each acre will produce 8 tons of protein per acre along with the oil, which can be used for feed for a wide variety of animals, including fish, poultry, swine and cattle.
Bio-refineries are energy centers that produce excess power and steam for export and sale. Thus, bio-refinery sites are the natural centers for food processing operations enabling greater utilization of agricultural fruit and vegetable production, and more security for farmers since excess crop production can be efficiently utilized. In both bio-refining and animal husbandry, waste streams can undergo anaerobic digestion which produces power and high value organic fertilizer.
What’s the carbon balance? In general, the majority of carbon emissions from biofuels come from release of soil carbon when original forests are cut down for plantations. Biological conservation areas should never be used for biofuels. For Hawaii’s agricultural lands, if the current use if forest, and it is replaced with biofuels tree crops, the net carbon balance is likely to be neutral from a soil carbon perspective, (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, carbon fixation tends to increase.
We will need to work together to achieve this vision. We need to recognize that just as natural systems evolve, biofuels will evolve as well. When we begin with importing biofuels, what matters most is not whether we are importing, but that we import fuels that are grown sustainably in order to prime the market for biofuels. We need a public-private initiative to launch the research and development on advanced crops now, so we can select the right crop for our lands.
The first biofuels plantations may not be perfect, but they will evolve as our knowledge of how to optimize productivity and sustainability improves with experience. State government has been very helpful in providing subsidies for investment and use of biofuels. We should be akamai, and not have our scarce tax dollars supporting oil companies and foreign plantations. The state biofuel tax credit subsidies shift from location-neutral to supporting only locally grown biofuels, once in state production commences in earnest.
Most importantly, we need to be committed to the long run to collaborating across boundaries to revitalize both our energy and agricultural sectors.
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* This article was written for the UH-based Hawaii Energy Policy Forum as part of an effort to encourage discussion of energy issues. Datta, CEO of Hawaii-based energy consulting and renewable development firm New Energy Partners, was managing director of Rocky Mountain Institute’s Consulting Practice. He co-authored Winning the Oil Endgame and Small is Profitable.
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