Economic Feasibility of Mesquite Biomass for Electricity Production: Projections of the Long-Term Sustainability of Two Harvest Options
Economic Feasibility of Mesquite Biomass for Electricity Production: Projections of the Long-Term Sustainability of Two Harvest Options
复制标题
豆科灌木生物质发电的经济可行性：两种收获方案的长期可持续性预测
作者：
Jaesung Cho;S. Park;R. Ansley;Seung;M. Mirik;Taewoo Kim
在美国西南部，豆科植物和类似的木本植物物种占据了超过2800万公顷的土地，它们经常通过减少牲畜饲料产量、增加裸地和干扰牲畜饲养来对农村经济部门产生负面影响。目前暂时抑制这些木本植物生长的控制方法包括除草剂喷洒、机械处理和规定的火灾。目前控制措施的一个替代方案是利用豆科植物生物质发电。本研究采用faustmann型模型，考察了豆科植物生物量作为潜在生物能源发电原料的经济可行性，该模型包含5种豆科植物生物量积累情景，考虑了采收后的直立生物量积累率和树木密度重建的变化，采收方式为地上全采（AG）或全采（WP）。然后将估计的再生函数纳入改进版的Faustmann模型中，以确定豆科植物的最佳收获长度，使使用豆科植物生物量的发电厂的净现值最大化。结果表明，豆科植物生物量具有作为发电资源的经济潜力。尽管AG的收获成本高于WP的收获成本，但AG收获后再生的长期生物能源收获系统比WP收获后从新幼苗发芽重建的成本要高得多。此外，利用豆科植物生产生物能源将增加来自这些土地的其他更传统的收入来源，包括放牧牲畜和野生动物狩猎租赁（有模式地收获豆科植物），并将减少通常用于木本植物控制的除草剂或机械成本。与传统煤炭相比，将豆科植物生物质用于发电的经济回报较低，但可能征收的碳排放税将使豆科植物生物质与传统煤炭竞争。
Mesquite and similar woody plant species occupy over 28 million hectares in the southwestern USA and often negatively affect the rural economic sector by reducing livestock forage production, increasing bare ground, and interfering with livestock handling. Current control methods that temporarily suppress the growth of these woody plants include herbicide sprays, mechanical treatments, and prescribed fire. One alternative to current control practices is to utilize mesquite biomass for electricity generation. This study examined the economic feasibility of mesquite biomass as a potential bioenergy feedstock for electricity production using a Faustmann-type model with five mesquite biomass accumulation scenarios, which take into account variations in rates of standing biomass accumulation and tree density reestablishment after harvest with the aboveground-only (AG) harvest option or the whole-plant (WP) harvest option. The estimated regrowth functions were then incorporated into a modified version of the Faustmann model to determine the optimal harvesting length of mesquite that maximizes the net present value of a power plant using mesquite biomass. Results indicated that mesquite biomass has economic potential to be a source for electricity generation. A long-term bioenergy harvest system with regrowth following AG harvest was much more cost-effective than reestablishment from germination of new seedlings after WP harvest, even though harvest cost is higher in the AG than that in the WP harvest option. In addition, the utilization of mesquite for bioenergy would enhance other more traditional income streams from these lands including livestock grazing and wildlife hunting leases (with patterned harvesting of mesquite) and would reduce herbicide or mechanical costs that ordinarily are necessary for woody plant control. Compared to conventional coal, a lower economic return was found when the mesquite biomass was used for electricity production, but a possible carbon emission tax would make mesquite biomass competitive with conventional coal.