Residue from forest, agricultural, and agro-industrial activities could be collected and converted. For example, the six million tons of waste produced annually by Niger could theoretically be used to meet that country’s entire energy needs.
因此，“能源作物”可以被开发以生产生物燃料。来自于森林、农业和农产业活动的残渣废料可以被收集起来并进行转化。例如，从理论上讲，非洲国家尼日尔每年产生的600万吨废料可以满足该国全部的能源需求。