中国中长期碳减排战略目标初探(Ⅵ)——碳捕集与封存排放目标讨论

乐观地估计,如果2050年允许中国排放二氧化碳80×108t,其中50×108t可排入大气层,剩余30×108t需要地质封存,碳捕集与封存(CCS)任务十分艰巨。预计可物理或化学利用的二氧化碳总量微乎其微,不会超过1×108t。从增产原油角度看,EOR将起到重大作用,但所占比率太小,从减排的宏观层面还应优先考虑"封存"。中国圈闭卤水层分布很广,潜在容量很大,选址相对容易,需加大适合二氧化碳地质封存的卤水层的地质选址研究。中国土壤有机碳储量仅50~100Gt碳,平均单位面积储碳量仅48.8t碳/ha,如果及时采取有效措施增加中国土壤的有机碳,今后40年应该可争取增储37Gt二氧化碳,相当于这期间累积二氧化碳排放量的1/10,可缓解碳排放的压力。岩溶对回收大气、附近地区土壤和水中的二氧化碳有明显作用,中国是名副其实的岩溶大国,宣传岩溶碳汇的作用,保护岩溶地区的地质、地貌和森林植被应该得到足够的重视。中国工业(制造业)部门排碳量太大,现在已超过欧盟。外贸输出了大量高耗能产品,净出口产品的二氧化碳排放量已占到国内二氧化碳排放量的13%～15%,这种高排碳量的外贸出口结构极不合理,调整产业结构、加大服务业的比重和增加外贸产品的科技含量有利于减少中国的二氧化碳排放量。中国目前关于CCS的文件和法规略显深度不够,执行力度不足,仍然是条块分割,划分为多个部门,各自为战,不利于CCS目标的实现。CCS工程所需资金额巨大,涉及社会、法律、教育、安全、金融等多方面工作,迫切需要政府集中力量,统筹安排,编制今后40年的CCS路线图和不同预案,纳入各时期的五年国民经济发展规划。

A Preliminary Study on China＇s Long and Medium-Term Strategic Goals for Reducing Carbon Emissions （Ⅵ）-- Discussions on Emission Targets for Carbon Capture and Sequestration

Optimistically,if China is allowed to emit 80×10^8t of carbon dioxide in 2050,50×10^8t could be emitted into the atmosphere with the remaining 30xl0at having to be sequestrated geologically.Therefore, the CCS task faced by China is very tough. Only a small amount of carbon dioxide ,which would not exceed 1×10^8t,is expected to be utilized,either physically or chemically.From the perspective of raising crude oil production,EOR will play an important role.However,as EOR＇s share is too small,priority should still be given to ＂sequestration＂ from the macro aspect of emission reduction. Brine formation traps are widely spread across China with great potential capacity, thus selecting sites for carbon dioxide se- questration would not be difficult.China should strengthen the study into selecting brine formations for the geological sequestration of carbon dioxide.China＇s soil organic carbon reserves are estimated at only 50-100Gt of carbon,averaging only 48.8t of carbon/ha.If measures are taken to effectively increase the content of organic carbon in soil,37Gt of carbon dioxide is expected to be sequestrated over the next 40 years ,which is equivalent to one tenth of the cumulative carbon dioxide emissions during that peri- od.Karst plays an important role in recovering carbon dioxide in the air,soil and water in its vicinity. China has many karst areas and should attach enough importance to publicizing the role of karst as a carbon sink and protecting the geology ,ground features and forest cover of karst areas.The Chinese in- dustrial （manufacturing） sector＇s carbon emissions are very high--they now have exceeded those of the European Union.China＇s foreign trade exports a large number of energy-intensive products.The amount of carbon dioxide emitted by the net exported products now accounts for 13%-15% of China＇s total car- bon dioxide emissions.This high-carbon emission structure of foreign trade is extremely irrational.Adjusting industrial structure, increasing the share of the service industry and raising the technical content of ex- ported products are instrumental to the reduction of carbon dioxide emissions in China.The depth of CCS documents and regulations in China still needs to be improved and the implementation of these rules should be strengthened.China＇s CCS regulatory authorities are highly fragmented and this has nega- tive effect on the achievement of CCS objectives.As CCS projects require large amounts of funds and involve a wide range of areas including social ,legal ,educational,safety and financial factors ,government support is badly needed. Such support includes unified planning, e. g. making roadmaps and contingency plans for CCS development for the next 40 years and incorporating them into national five-year eco- nomic development plans.