推广能源作物与生质柴油之政策效果与整合分析

Analysis of Policy Integration to Support Production of Energy Crops and Biodiesel

再生能源为当前各国致力发展之替代能源,旨在建立模型描述能源作物与生质柴油之供给者与需求者行为,观察政策对要素及产量供需之影响,可发现提高种植能源作物之单位面积补贴,会将使其种植面积及产出增加:提高生质柴油单位产量补贴,将增加能源作物需求及生质柴油供给,由于上述分析未考虑市场间之影响,可视为政策之短期效果。接着利用市场供需均衡原则,分别推导两个市场之均衡价格,进而了解政策对均衡价格之影响及政策变量间之相关性,发现提高能源作物或生质柴油补贴,将分别使其均衡价格下降;然而生质柴油补贴对能源作物之均衡价格则为正向影响。由于政策会影响价格,但在短期政策分析时并未考虑价格变动效果,长期若加入价格变动效果则会发现政策对要素及产量供需之影响均为不确定,亦即政策短期有效,但长期效果不定．在市场均衡下,能源作物与生质柴油补贴为正向关系,而生质柴油补贴与燃料税亦为正向关系．最后设定一社会福利极大化模型,在政府政策目标与预算限制下,观察政策变量问之相关性,发现能源作物补贴与其它燃料税率为正向关系,表示当政府提高燃料税的同时亦要增加能源作物的补贴．在社会福利模型中,其它燃料的税率弹性为政策决定的关键因素,当消费者对其他燃料需求的税率弹性大于-1时,政府应该对能源作物与生质柴油进行补贴。

Both decision maker and environmentalist have recognized the important role that biofuel and energy crops could play in the era of pursuing sustainable development. Accordingly, a minimal share of renewables, including biofuel, is targeted in energy portfolio of many countries. To achieve the targets, policy instruments such as subsidy of various types, renewable portfolio standards and tax exemption are provided. As these instruments are administered by different authorities, their effective integration has turned out to be uncoordinated and unguided. The policy integration is made even more complicated and difficult due to the interaction between newly introduced instruments and existing relevant instruments for other policy goals. Taking biodiesel for example, we apply the principal-agent approach to model the behavior of such agents as energy-crop producer, biodiesel producer and fuel consumer. The optimal policy integration is then examined under two circumstances representing different goals of the principal. The results indicate that optimal rule of integration is pretty much goal-dependent. Consistent adjustment of existing instruments may be required if new ones are to be introduced to achieve given objectives.