【作者】 曹历娟；

【导师】 朱晶；

【作者基本信息】 南京农业大学 ， 农业经济管理， 2009， 博士

【摘要】 为了抑制不断攀升的石油价格及有效解决温室气体排放所带来的环境问题,燃料乙醇作为一种清洁的能源已经引起了世界范围的广泛关注。一方面,燃料乙醇的出现实质上提供了一种新能源的供给,有利于缓解一国的能源压力；另一方面,燃料乙醇的原料主要是玉米、小麦,不可避免地出现“与人争粮”,“与粮争地”的矛盾,对保障粮食安全不利。我国自本世纪初开始发展燃料乙醇,至今已经初具规模,并一跃成为世界上第三大燃料乙醇生产国。客观地讲,燃料乙醇的发展对缓解能源安全压力有一定的贡献,特别是在满足汽车用汽油的需求方面。但是,在世界粮食危机的背景下,发展燃料乙醇对我国粮食安全的负面影响越来越为人们所重视,国家甚至出台措施叫停燃料乙醇的发展。那么,在我国是否仍具有发展燃料乙醇的空间呢?本研究以我国粮食安全和能源安全的紧迫性对比为切入点,分别从供需缺口、世界市场供给情况以及我国进口与世界产量时点波动趋势角度对我国的粮食安全和能源安全进行了系统的研究,结果表明：现阶段我国能源安全,特别是石油安全,受国际石油危机影响较大,石油安全的保障有较大难度；而粮食虽然存在较大的供需缺口,但我国依然可以利用国际市场平抑粮食供需缺口,我国的粮食安全在现阶段受到的威胁有限。从紧迫性的对比来看,在我国发展燃料乙醇仍具有可行性。燃料乙醇的发展以及进一步发展对我国的粮食安全和能源安全造成的影响是政府和学术界关注的另一个焦点。为了对该问题做全面且深入的探讨,本研究将通过一般均衡模型对此进行模拟分析。具体来看,研究将分别模拟我国燃料乙醇发展的不同阶段对粮食安全、能源安全以及总福利的影响。根据现实的情况,研究中设置了两种情境：燃料乙醇的产量达到2006年我国产量135万吨(即现实情况)以及燃料乙醇继续发展,产量达到国家在《可再生能源中长期发展规划》中设置的1000万吨的中长期目标。为了便于在GTAP模型中的模拟和操作,本研究将燃料乙醇发展对粮食安全、能源安全等的影响分别为两个方面：一个是玉米需求增加带来的效果,另一个是石油供给增加带来的效果。本研究认为,发展燃料乙醇带来的效果基本上可以等同于这两个效果之和。通过一般均衡的模拟,本研究得到以下的结论：1、在本研究设置的情境下,现阶段燃料乙醇的生产对我国其他粮食产品安全的保障影响不大；但当燃料乙醇发展到1000万吨时,虽然稻谷、小麦的播种面积从比值上看变化不大,并不足以威胁口粮的安全,但从绝对值看,共计4000千公顷的小麦、稻谷用地会转化成玉米用地。随着燃料乙醇产量的增加,“与粮争地”会更加严重；对玉米而言,当燃料乙醇产量为135万吨的时候,玉米的供需缺口会有小幅增加,玉米的净进口量也会有所增加,我国玉米安全会有一定的恶化,但不会造成玉米不安全状况；燃料乙醇发展到1000万吨的时候,经计算玉米的粮食安全仍能得到保障,但无论从居民价格还是进口依存度方面,我国的玉米安全都受到了很大的威胁。当燃料乙醇的数量再继续增加的时候,玉米贸易逆差就有可能出现,甚至出现玉米不安全的状况。2、发展燃料乙醇对我国畜牧业以及食品加工业无论在生产、消费还是价格方面影响都不是很大,并没有出现大家所担心的与畜牧业与食品加工业争原料的问题。3、发展燃料乙醇对我国的主要能源部门,例如煤炭、天然气等能源部门以及高能耗产业的生产、消费以及产品价格等方面造成的影响较小。当燃料乙醇产量达到1000万吨的时候,其发展对石油、.汽油的产量、消费量以及价格、净出口金额造成的影响相对较大,虽然不能从根本上解决我国的能源问题,但一定程度上缓解了我国对汽车用汽油需求的压力。4、基于发展燃料乙醇对粮食安全有负面影响,却有利于保障能源安全,其发展对整体福利影响的方向很难确定。根据GTAP模型模拟的结果,发展燃料乙醇会减少居民家庭收入,但是却能增加GDP金额。从部门考虑,农业生产者可以从中获得更大的福利,但农产品消费者会受损；制造业生产者会受损；而服务业生产者福利应该会上升；从要素所有者收益的角度,土地要素的所有者会从燃料乙醇的发展中获利,且幅度较大,劳动力资本的所有者也都会从中获利,只有自然资源的价格会有所下降。其中,获利最多的应该是土地资源的所有者。从上述研究结论中可以发现,在本研究设置的两种模拟情境下,我国的粮食安全和能源安全虽然都受到了一定的影响,但我国粮食安全和能源安全的性质并没有发生根本的逆转。随着我国燃料乙醇产量的增加,粮食安全受到的威胁将会继续增加,而能源压力会不断缓解,一旦燃料乙醇的产量增加到某个数量时,粮食安全状况就会达到变化的临界点,能源安全也会如此。这两个临界点便是国家在保障粮食安全或者能源安全的目标下燃料乙醇的发展边界。研究拟从国家的政策目标出发,探讨国家在保障粮食安全的前提下,所能发展的生物能源的上限。通过使用GTAP模型倒推,本研究得出如果以粮食安全为目标,要想保证玉米的自给自足,可以选择3000万吨作为燃料乙醇产量的上限。在该方案下,玉米价格变动最大,其他的粮食产品的变动仍不会太大,而畜牧业、食品加工业因为生产成本的上涨导致价格上涨,但变动幅度不大,其消费和世界价格会有小幅度的下降,保障食物安全的难度不大。同时,当燃料乙醇发展到3000万吨时,虽然燃料乙醇的发展还不足以弥补我国石油的供需缺口,但它对缓解我国石油进口压力有明显的作用；如果国家以保障能源安全为导向,国家需要进口折合成20000万吨以上的玉米,这种情况在世界普遍发展燃料乙醇的现阶段基本不具有可行性。据此,本研究认为完全靠发展燃料乙醇保障我国的石油安全不切实际。根据以上的研究成果,本研究得出以下政策建议：1、现阶段,面对日益严峻的能源危机,在我国发展燃料乙醇具有一定的可行性。但是粮食安全对于我国而言有极其特殊的意义,据此,研究粮食安全导向下我国燃料乙醇的发展边界有非常重要的现实意义。通过GTAP模型的模拟,本研究得出要达到保障粮食安全的目的,我国燃料乙醇的产量要控制在3000万吨以内。这个数字跟我国实际的燃料乙醇产量有很大的差距,我国在燃料乙醇的发展上仍大有可为。笔者建议,在既想生产更多乙醇燃料,又想保证粮食安全的情况下,应该建立粮食安全预警体系,随时对粮食安全进行监控,从而达到两者的最佳协调。2、保障能源安全,特别是石油的安全,仅靠发展玉米乙醇是远远不够的。石油安全的保障需要通过其他的途径。诸如使用秸秆、薯类等非粮食产品生产生物质能源之类的措施,在我国有一定的可行性和可操作性。更多还原

【Abstract】 To reduce the ascending energy price and solve the environmental problems arising by the emission of greenhouse gas, corn ethanol, as a clean energy is concerned by all of the countries over the world. On one side, corn ethanol, which exists as the substitute of traditional energy, can ease the pressure from energy security. On the other side, it will threaten food security, as its materials are mainly corn and wheat, which are also used as food and feed.Since 2000, China has commenced to develop the corn ethanol, and now it becomes the world’s third manufacturer. Truly, the development of corn ethanol is favorable to China’s energy security, especially to meet the demand of petrol for cars. However, under the background of World’s food crisis, its disadvantage to China’s food security is more concerned. The government even chose to suspend its development in 2006. Therefore, the question is whether there is any possibility to develop corn ethanol in China.The thesis will analyze it from the angle of the comparison of the urgency between China’s food security and energy security. By studying their lap between supply and demand, the world supply and the fluctuation tendency of China’s import and world’s production individually, it indicates that China has the ability to guarantee its food security, even under the background of world’s food crisis. However, it is hard to ensure its energy security, as the world oil crisis really hinders its security. Therefore, energy security turns out to be more urgent in China now. So it is implied that there is still some space for the developing of corn ethanol.Then, what is the result of China’s developing of corn ethanol? If the development is resumed, what will the further result to food security and energy security? The dissertation will illuminate it through the simulation by CGE model.To study the impact of the different stages of the developing of corn ethanol on food and feed security, energy security and welfare, we set two scenarios:One is the production of corn ethanol up to 1350 thousand tons, which is close to the reality in China now. The other is the production reaching 10000 thousand Tons, which is equal to the production of USA in 2006. According to the relationship between input and output, the impact of the developing of corn ethanol can be divided into two parts:One is brought by increasing the corn demand, and the other is from the increase of the oil supply. It is supposed that the impact of the developing of corn ethanol is equal to the sum of two parts.Through simulation, the conclusions are listed below:First, under the both scenarios, the developing of corn ethanol has little effect on the food security of other cereals, except corn, judging from the change of their prices, productions, sown areas, consumptions, trade values and world prices. Concerning corn, under the first scenario, the food security of corn will be worsening, as the price will be increased, and net import will also be enhanced. When the production is up to 10000 thousand tons, the food security can still be ensured. But the threat will be more severe. It can be referred that the food security of corn will be in danger if the production of corn ethanol continues to increase.Secondly, the development of corn ethanol will not effect the feed security, taking the production, consumption and price of meet and processed food for considerationThirdly, the development of corn ethanol has little impact on coal, gas and energy-intensive industry under the two scenarios. Concerning oil and petrol, the effects are bigger. But it still can’t solve the energy crisis, but only release the demand of petrol for car.Moreover, considered China’s total welfare, the development of corn ethanol will increase the household income, but reduce GDP value. Referred to the different sectors in our country, the producers in agriculture will benefit, while the consumers in agriculture will lose. The producers in industry will lose and at the meantime, the producers in service will benefit. As per different factors, the owners of land will benefit most. The owners of labor, no matter skilled or unskilled will also benefit from its development.The content of the 10th chapter will search a proper policy of corn ethanol’s development, subject to the goal of food security and energy security. It is proved, the maximum of corn ethanol’s production is up to 30000 thousand tons, if you want to ensure the food security. It is impossible to rely on corn ethanol to solve our oil crisis.According to the study, the suggestions are:Firstly, it is proved that China can enhance its production of corn ethanol considering the urgency of food security and energy crisis. But food security is so important in China that we have to find a proper policy for the development of corn ethanol, which is subject to food security. It is calculated the maximum of corn ethanol is 30000 thousand tons. Therefore, there is still some space for corn ethanol. Besides its development, we should build up a warning system to announce the situation of food security often.Secondly, to guarantee our energy security, it is not feasible to rely only on corn ethanol. Diesel oil is also a good choice for China.更多还原