The direct discharge of large amounts of CO_2 from coal-fired power plants has a serious negative impact on the environment. The conversion of captured CO_2 and H2 generated from renewable energy sources into CH_4 is encouraged for both environmental protection and energy conversion and storage. In this work

the process of CO_2 capture combined with CO_2 methanation was simulated and analyzed. Meanwhile

the energy consumption

net CO_2 emission and cost of CH4 were evaluated. The results show that

the CO_2 capture efficiency can reach 79%

a high purity CO_2(98%

mole fraction) stream is obtained and then transformed to CH4. Finally

a product gas with 91%～94% CH_4 can be produced. When hydrogen is produced from renewable energy sources

the total energy consumption of this process can be significantly reduced and a net carbon emission reduction can be achieved. This combined process can be driven to economically attractive when the cost of hydrogen production from renewable energy sources is greatly decreased in the future or a large amount of cheap hydrogen is available

which is expected to become one of the important technologies for large-scale utilization of captured CO_2 from coal-fired power plants.