Fig. 4: Spatial disparity and temporal dynamics of theoretical GHG emission intensity from solar PV power, expressed in kg CO2e per kW.
a Theoretical GHG emission intensity of a functional unit of monocrystalline silicon PV in 2009. b The same as (a) but for 2019. The driving factors (c) and processes (d) associated with production of intermediate and final products for the decline in GHG emission intensity for China from 2009 to 2019. CE represents the impact of improvement of conversion efficiency; Si, Ele., and Heat represent the impact of declines in consumption of silicon, electricity, and heat; GEF represents the impact of the decline in average emission factors for grid power. The figure shows GHG emissions from production of metallurgical grade silicon to the active phase of the solar PV power generation system. The emissions during disposal and recycling processes, and the associated reduction of GHG emissions from using recycled materials during manufacturing, were not considered here because the disposal and recycling of systems were uncommon in these early years of the industry. Such processes are considered in the future projections discussed in the next section.
