Study On Estimation Method Of Ecological Value Of Bio-nature Gas Project Based On Straw Natural Decomposition Baseline

Straw bio-nature gas project is the main way of new energy utilization in the comprehensive utilization of crop straw in China.It is of great significance to deal with agricultural waste,reduce air pollution,improve ecological environment and realize rural revitalization.This study focused on bio-nature gas project,constructed the measurement method of greenhouse gas emission reduction and estimation method of ecological value of bio-nature gas project,and calculated the greenhouse gas emission baseline of natural decomposition of corn straw through experimental research.Combined with field investigation,the greenhouse gas emission reduction measurement method and ecological value estimation method of straw bio-nature gas project were used to evaluate the emission reduction potential and ecological value of bio-nature gas project in Linzhang County,Handan City,Hebei Province.（1）According to the experimental study,the greenhouse gas emission baseline of natural decomposition of corn straw was obtained.In view of the gradual reduction of straw burning,the greenhouse gas emission baseline of natural decomposition of corn straw was studied by simulating the scenario of corn straw dumping in the field and ditch.The natural decomposition of corn straw on the land will release CO₂,CH₄,N₂O and other greenhouse gases,the main source of emission is CO₂.In the terrestrial scenario,the baseline greenhouse gas emission of natural decomposition of corn straw（dry weight）is CO₂ emission of 830.1809 g·kg^-1,CH₄ emission of 0.2317 g·kg^-1,and N₂O emission of 0.1356g·kg^-1.In the underwater scenario,the main emission sources are CO₂ and CH₄.In the underwater scenario,the baseline greenhouse gas emission of natural decomposition of corn straw（dry weight）is CO₂ emission of 121.6878 g·kg^-1,CH₄ emission of 14.5961 g·kg^-1,and N₂O emission of 0.1359 g·kg^-1.（2）According to the three steps of"alternative substitution→greenhouse gas emission reduction→ecological value",the measurement method of greenhouse gas emission reduction and the estimation method of ecological value of bio-natural gas project are constructed.Firstly,the baseline is determined,and calculate the baseline emission.Secondly,calculate the greenhouse emission in the production process of bio-nature gas project.Thirdly,calculate the leakage emission of the project.Finally,the greenhouse gas emission reduction of straw bio-nature gas project is calculated according to formula=--.Through the net greenhouse gas emission reduction of straw biogas project,the ecological value(1of straw biogas project was quantified by carbon trade price₂.（3）The greenhouse gas emission reduction potential and ecological value of Linzhang bio-natural gas project were evaluated quantitatively.In 2019,the baseline emission of the straw bio-natural gas project in Linzhang County is 125,325.58 t CO₂,the project emission is 12064.60 t CO₂,the leakage emission is 10.24 t CO₂,the net emission reduction is 113,250.74 t CO₂,which is equivalent to the CO₂emission of 41944.72 t standard coal.For every 1 t of straw consumed in Linzhang County,871.16 kg of CO₂ emissions will be reduced,and for every 1 m³ of biogas produced and utilized,8.41 kg of CO₂emissions will be reduced.In 2019,the ecological value of the straw bio-nature gas project in Linzhang County is 3,488,100 yuan.For every 1 t of straw consumed,the ecological value can be 26.83 yuan,and for every 1 m³ of biogas produced,the ecological value can be 0.26 yuan.