Comparison Of Material Flow And Energy Flow Between PV Power Generation And Thermal Power Generation

Coal-fired power generation is the primary method for generating electricity.With the growing concern about environment protection,coal-fired power generation is developing towards the direction of becoming more efficient,energy-saving and eco-friendly.As a major representative of the renewable energy power generation,photovoltaic power generation still has a long way to go.How would the promotion of manufacturing process affect energy and material consumption when power plants update their generation process for energy-saving?How would the extension of system boundary by including manufacturing process affect the efficiency of power generation?To answer these question,this thesis performed an energy flow analysis and a material flow analysis to compare the efficiencies of a 200MW photovoltaic power plant and a 30 MW coal-fired power plant from a life cycle perspective.The thesis employed life cycle assessments of the two power plants in Simapro and the data were mainly obtained from EcoInvent(Simparo's database),practical survey and literature review.This thesis found that the coal-fired power plant can generate a total of 8.64 X 106MWh electricity and 3.25 × 107MWh heat in its whole life,in which the largest proportion of energy is consumed in the operation phase.The energy consumption of operation phase is 1.47 × 106MWh,which is 17%of total generation electricity.In contrast,the photovoltaic power plant can generate 5.62 × 10MWh electricity in its whole life cycle and the most energy consuming phase is the production of Polycrystalline silicon wafers,and that phase consumes 7.17 × 104MWh,which is 1.28%of total generation electricity.The energy consumption in the manufacturing phase of the power plant is 8.15%of total energy consumption for coal-fired thermal power plant.The energy consumption in the manufacturing phase is 92.58%of total energy consumption for photovoltaic power plant.Proportion of total energy consumption between photovoltaic power plant and coal-fired power plant is 0.28:1 of each 1kWh electricity generated.In manufacturing phase,energy consumption of photovoltaic power plant is 6.4 times coal-fired power plants'.In operation phase,energy consumption of photovoltaic power plant can be ignored.From the perspective of the life cycle,efficiency of coal-fired power plant is 78.83%,lower than traditional energy efficiency.For photovoltaic power plant,it is 14.02%,lower than traditional energy efficiency too.Energy efficiency of PV/T is 49.1%.On the other hand,power generation ratio of 300MW coal-fired plant is 7%higher than 35MW coal-fired one.The paper also compared energy consumption between different coal,and finally found that all energy consumption of coal mining and transportation is higher than other phase.The result showed that the database in simapro doesn't match Chinese situation.The paper found that GWP and of coal-fired thermal plant is higher than PV plant while other environmental impact is lower than PV plant when generating 1kWh electricity.The environmental cost of coal-fired thermal plant is lower than PV plant.