An ethanol plant located in the area around Grand Forks, North Dakota, could find an ample supply of inexpensive feedstocks according to a recent study.
Enough potato and grain-mill waste comes from three plants around Grand Forks to produce an estimated 12.5 million gallons of ethanol per year. The largest volume of wastes in the region comes from sugar beet pulp and molasses, but these are currently sold as animal feed and command significantly higher prices than would be economical for conversion to ethanol. There is also a sufficient amount of wheat and corn grown in the region that would be available to augment the lower value and more seasonal waste feedstocks.
The study recommended a hypothetical mixture of feedstocks necessary to supply a 15-million gallon per year plant. As conceived, about 340,000 tons of potato wastes at no-cost could be combined with 120,000 tons of grain-mill waste at $50 per ton from the North Dakota State mill and augmented with 28,000 tons of corn valued at $71.40 per ton--the equivalent of $2 per bushel--to produce 15 million gallons of ethanol per year.
By locating the plant near the Simplot potato facility, waste transportation costs could be minimized. The area around the potato processing facility is a developed industrial area with sufficient utility and transportation infrastructure necessary for an ethanol plant. An ethanol plant would require about 5 acres of land. The study suggested that additional infrastructure improvements would not be needed to support the ethanol plant.
A 15-million gallon plant is estimated to cost $27 million and would generate an estimated $15 million in gross revenue per year and employ 20 people. Markets for the ethanol produced in the plant are generally in nearby regions, especially Minnesota to the East and Montana and Wyoming to the West, which are net ethanol importers. Rail access is readily available to ship ethanol to markets in the Northwest.
A second corollary study of a larger area surrounding Grand Forks examined feedstock options and technological, economic, environmental and infrastructure considerations related to the feasibility of a cellulose-based biomass-to-ethanol plant in the region.
Reliance on biomass resources within the region can be a considerable constraint on the feedstock requirements of a 20-million gallon per year regional ethanol plant. The study estimated that feedstock requirements could range from 182,000 to 459,000 bone dry tons.
Agricultural Resources--crop straw, corn stover, and potato and sugar beet waste--in the region are substantial, but are either already committed for higher value purposes or may have collection, transportation and handling concerns. The use of straw would require considerable storage to meet the year-round needs of an ethanol plant. The cost of straw may be determined by other regional uses, especially strawboard plants capable of paying $30 to $35 per ton for baled straw. A variety of waste products from agriculture processing plants may hold the best promise for use in ethanol plants.
Forest Resources within the region are variable and may not be available because of transportation costs and access. Aspen resources in Northwestern North Dakota would only supply enough material for a 5-million gallon per year plant, not one 3 to 4 times that size. And this resource may be too costly--estimates are that the trees would cost between $45 to $60 per bone dry ton. The only areas with sufficient forest resources to meet the needs of a large ethanol plant are in North Central and Northeast Minnesota. It is estimated that a 20-million gallon plant would require 234,000 tons of wood per year.
Waste Wood Resources in the region may be inexpensive or free, excluding transportation costs which could be considerable. While Minneapolis/St. Paul generates sufficient wood waste for a 20-million gallon plant, a plant in Cass Lake, Minnesota, would need to collect wood waste from a radius of 100 miles or more. All the wood waste in North Dakota would be enough for a 17.2-million gallon plant at a central location, according to the study, but no urban area in the state could fulfill that need by itself.
Energy Crop Resources are ideal for biomass-to-ethanol conversion but can be more costly to produce than other resources. While hybrid poplar trees have been promoted as an ideal feedstock, the clay soils in the Red River Valley are unsuitable for growth and rainfall is insufficient in Western regions in the study area. Only areas in Minnesota would be ideal for growing hybrid poplars for use as an ethanol feedstock. Estimated cost and harvest potential of poplar production are 3 tons per acre for 12 years at $82 to $85 per dry ton. Poplar startup costs are estimated at $285 to $338 per acre. Switchgrass has been promoted as a potential energy crop as well. Oak Ridge National Laboratory estimated switchgrass grown in the study area would yield about 4.4 tons per acre per year in North Dakota and 5.4 tons per acre per year in Minnesota. Production costs were estimated at $27.36 to $49.27 per ton. Use of grasses for ethanol production is hampered by uncertainty of enough feedstock within close proximity of the plant to meet production needs.
Technological issues considered in the study examined the variety of biomass-to-ethanol plants being developed including those using sugar cane waste, wood waste, rice straw and municipal solid waste.
A state-of-the-art biomass-to-ethanol plant is estimated to cost $5 per gallon of capacity, or $100 million for a 20-million gallon per year plant. The cost to produce ethanol at the plant is estimated to range from $1.30 to $1.50 per gallon. In the near term, the National Renewable Energy Laboratory expects biomass-to-ethanol plants using free or inexpensive feedstocks such as forest and wood waste to be cost competitive with grain-based feedstock plants. Utilization of more expensive feedstocks, however, will not likely be cost competitive for some time.
Environmental issues examined in the study included the need for air emissions permits for minor amounts of vapors, particulates and solid products. Avoidance of flood plains and environmentally sensitive areas is desirable.
The examination of infrastructure issues associated with a plant concluded that water and power needs are essential. A 20-million gallon per year plant is estimated to need 500 million gallons of water per year. Access to a wastewater treatment plant is essential. Increasingly, a number of ethanol projects are being paired with powerplants or other types of facilities to maximize related coproducts such as electricity, steam or feed grain byproducts.
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