(2) sugar recovery followed by combustion of the fiber. An alternative to the module would be in-field sampling using the Hawaii sugarcane industry field trial (FT-7) procedure. A comparison would be made of whole-cane versus burned-cane harvesting. Sweet sorghum: An area of 10 to 50 acres per module would be needed following the procedure outlined above. The output would be sugar recovery as molasses for fermentation with combustion of the fiber. b. Economic feasibility analyses: The feasibility of energy grasses for specific sites (e.g., abandoned sugarcane lands on which irrigation is still economically feasible) and specific end uses need to be studied. This should also include energy cane production or good soil field tests. c. Varietal research: There is need for short-term evaluation of existing cultivars grown in energy-grass management systems. A suitable long-term hybridization study should to be initiated within and between species and genera with the objective of maximizing biomass productivity. It is believed that the genetic potential of intergeneric hybrids in terms of energy production probably has not been exploited. d. Energy-grass species trials: Trials are needed to establish the comparative performance of the tropical grasses. Variables that likely would need to be included are species, irrigation, and nutrients. A state-of-the-art assessment of herbaceous crop options for liquid fuel or lignocellulose products is also desirable. C. ALGAE 1. Issues While algae appear to offer great potential as sources of fuels, there is as yet no significant commercial fuel production experience. Algae have been used for wastewater purification, where algae can be harvested and anaerobically digested to produce methane, which in turn may be used as a source of energy and thereby improve the economy of the overall process. Present commercial production is primarily for food and other high value products on a relatively small scale. Fuels, however, are presently relatively low value products. To be competitive with present conventional fuels, the cost of large-scale growth, harvesting, and conversion of algae to fuels must be drastically reduced through process improvement and co-production of higher value products. a. Requirements were listed for biofuels production under fuel catetories: (1) Methane 2. (3) Hydrocarbons (4) Hydrogen The consensus was that alcohol-from-algae is not promising compared to other means of producing alcohols in Hawaii, so it was excluded from further consideration. b. Requirements and specifications for biofuels production: (1) Both micro- and macroalgae are promising candidates for energy production. (2) Algae should be grown in an integrated system in which (3) The most promising near-term product is methane. Hydrogen, lipids, and other potential production are more long-term possibilities. (4) The system should be sized to correspond to desired energy output. (5) Details of system: The system will not be covered. Depth of the microalgal culture system will be 4 to 10 inches. Oxygen supersaturation can be dealt with in two ways: (a) add wastewater containing BOD in a system driven by paddlewheels; or (b) use airlifts to move water. Flow rates in microalgal systems will be 6 to 12 inches/second Methane will be produced from microalgae using facultative ponds. Semicontinuous culture appears critical to high microalgal production. Size (area) of individual microalgal flumes will be 1 to 5 acres. Construction and operating costs must be minimized. (6) A combined micro-macroalgae culture system may be most efficient, with macroalgae used to polish effluent from microalgal system. Priorities There are hundreds of species and strains of algae, most of which have not been characterized as to composition, optimum growing conditions, and other properties of importance to the design of commercial production facilities. In the USDOE/SERI microalgae program, species are being collected and characterized for high lipid production in the saline and brackish waters available in the southwestern United States. The Gas Research Institute is supporting research in methane production, primarily from macroalgae. Relatively little attention is being given to marine or freshwater species for Hawaii and the Pacific Basin. For methane production from microalgae, "anything that grows" (to Pladymonus and Chaetoseros Local species of 3. Grassilaria, Ulva, and Sargassum are desirable species of Microalgae known to be good lipid producers are Botryococcus, For biological production of hydrogen the microalgae Chlamydomonus Action Program Research needs: a. Complete integrated algal growth and harvesting systems, c. Carbon dioxide losses are high in present culture facilities. d. Species screening and characterization research are very e. Mechanisms and conditions for inducing lipid production by f. Harvesting research is needed, including techniques, equipment, g. Methane production from microalgae using facultative ponds is h. Biological hydrogen production research needs are primarily i. Use of seawater and sewage mixtures should be explored. -20 H directly applicable to the Pacific Basin, although many Hawaii specific problems will remain to be solved through research that must be performed here. Future research programs must be designed to take these considerations into account. Also the great potential of OTEC related algae production should be fully researched, using the facilities of the Natural Energy Laboratory of Hawaii (NELH) on the Big Island. 2. Solid wastes considered were categorized into three distinct types: municipal, agricultural, and animal wastes. Municipal wastes were characterized as heterogeneous, with materials in the mixture ranging from newspaper and paper products to glass, metallic materials, and other inert products. Municipal sludge after various treatments is also included. Agricultural waste is considered homogeneous by the solid waste standards because most of it is cellulosic fiber either left in the field to plow over or collected at the processing plant for future disposal. The materials considered agricultural wastes are sugarcane leafy trash and pineapple chop. Most other wastes of this type are small in quantity or have other specific uses. The final type considered was animal waste. Because Hawaii's feedlots are limited in size and quantity, animal waste was considered negligible for further consideration. Priorities a. The key objectives for solid waste biomass energy are based on the following needs: b. The primary and most common method for waste disposal, since ocean dumping has been ruled out, is land disposal or landfills, the most common method of solid waste disposal. However, there are a number of problems with landfills in Hawaii: land availability and the subsequent cost have been restricting factors in recent years. Water table contamination from leaching chemicals also poses a serious problem. c. Waste disposal via incineration is an immediate remedy to the 3. d. Liquid fuel production is another method that would reduce solid waste. While the technology is proven, however, its economic cost and market are undefined. e. Electrical power generation via incineration is then the most promising process. The feedstock can be municipal solid waste as well as agricultural wastes (i.e sugarcane, pineapple, maize, and other products). The volume of feedstock is reduced 90 percent, with the 10 percent residue environmentally acceptable for landfills. (It cannot be assumed that residues from incineration are environmentally acceptable. It also cannot be assumed that stack emissions are safe.) The technology has proven commercially and economically feasible to various sizes of production plants. Assuming separation will be part of the process, then glass, metals, and paper can be recycled. Action Program Electrical power generation via incineration with commercial and economical technology should be pursued, since landfills will soon be unavailable to handle the large volume of solid waste collected. As biofuel generation technology improves, as the economics become cost-effective, and as alternative electricity production becomes available, then sugarcane bagasse and other agriculture waste could be used as feedstocks for biofuel generation. The following tasks are recommended: a. Investigate methods via alternate energy to remove water from sewage sludge to an acceptable moisture content for incineration. Present mechanical methods (i.e. mechanical press and centrifuge) are able to dewater sludge to a 65 percent solids content, thus oil must be added to incinerate the sludge. b. Follow the conversion technology task group's recommendations to accelerate the conversion process to a cost-effective state. c. Identify the by-products, residues, and methods from the biomass to liquid or solid fuel conversion process to augment the final disposal. Transportation fuels should be the first priority for the use of |