In order to make the best choice for $CO_2$ abatement using renewable energy technologies, it is important to be able to adapt these technologies on the basis of their sustainability, which may include a variety of environmental indicators. This study examined the comparative sustainability of renewable technologies in terms of their life cycle $CO_2$ emissions and embodied energy, using life cycle analysis. The models developed were based on case studies of bioenergy pilot plant in P city of Kyungki province. Final results were total emission of $CO_2$ in Pocheonsi is 670,041 $tCO_2$, around 500,877 $tCO_2$ for electricity and for heat generation, and 169,164 $tCO_2$ for transportation. When used $1,984;m^3$/day of waste (pig manure etc.) and operated CHP with wood chips of 144,664 ton/year, the $CO_2$ emission in P city was left as is an emission of 449,274 $tCO_2$ and an abatement of $CO_2$ in this region was increased by 32.9%.