Multi-model Based Assessment On Generation Potential With Associated CO₂ Emission Reduction And Water Saving Potential Of Large-scale PV In China

As the fastest developed renewable energy power generation technology,large-scale PV plays a crucial role in low carbon transition of China’s energy structure.Since China faces the challenge of continuously increasing power demand,CO₂ emission and stressed water supply.A scientific knowledge of the large-scale PV generation potential and associated CO₂ emission reduction and water saving potential in China would provide decision-makers with practical suggestions for achieving better system.Current research on solar energy potential still exist issues to be solved,such as insufficiet factors considered and relatively low resolution.In addition,very few studies address the CO₂ emission redution and water saving benefits of PV generation from a life cycle perspective.This study first builds a Geographic Information System-based model to calculate the large-scale PV power generation potential with a high resolution,with the consideration of the geographical and technical constraints factors.Then this study innovatively draws the province-specific generation potential map,and observes the changes of the potential under different land selection criteria and technical conditions.This study conducts a life cycle assessment on large-scale PV,and quantified the CO₂ emission reduction intensity and water consumption intensity from a life cycle perspective,and draws the map on China’s CO₂ emission reduction and water saving potential associated with large-scale PV generation potential at the provincial resolution,then further conducts a carbon-water nexus calculation.In the last part,this study conducts scenario analysis and discussions based on China’s carbon intensity reduction commitment and regional water stress index.The results show a potential installed capacity of 1.41×10⁵ GW,corresponding to an annual power generation of 1.38874×10¹⁴ k Wh or 20.3 times national electricity consumption in China 2018.On a provincial level,while generation potential in Northwest and Inner Mongolia together account for 86%of the total,China’s eight economically developed coastal provinces only account for 1%.The results of sensitivity analysis shows that about 49%of suitable lands for large-scale PV installations has a slope less than 3degrees and annual global horizontal irradiance over 1600 k Wh/m²,accounting for 55%of national generation potential.In addition,for every 1%increase in the effciency of PV system within the range of 14–24%,the overall potential would increase 6.76×10¹² to 1.04×10¹³ k Wh,which represents 0.99–1.52 times of China’s national electricity consumption in 2018.The results of life cycle assessment shows a water consumption intensity of 0.75L/k Wh,which is significantly lower than that of coal-based power generation.Under a maximum large-scale PV scenario,the results show there is 2.72×10⁹ t,2.93×10⁹t and3.06×10⁹t of CO₂ emission reduction potential in China during year 2015-2017,making up for 29.43%,31.84%and 32.94%of China’s yearly national CO₂ emission.The results of sensitivity analysis show that a reduction in China’s carbon intensity（adjusted for gross domestic product）of 63–68%compared to 2005 would result,which is suffcient to meet China’s CO₂ emission reduction commitment.And the water saving potential in China during year 2015-2017 is 2.29×10¹⁰ m³,2.44×10¹⁰ m³ and 2.58×10¹⁰ m³,accounting for3.75%,4.04%and 4.27%of China’s national yearly water supply or 17.14%,18.67%or20.20%of water supply on industry sector,respectively.The results of carbon-water nexus calculation show that Fujian and Guangdong have both high CO₂ emission reduction and water saving potential,while other coastal developed provinces with insufficient generation potential have the lowest CO₂ emission reduction and water saving potential.Provinces in South Central and South West China has high water saving potential and low CO₂ emission reduction potential,on the other hand,the situation for provinces in North China,especially in North West China is the opposite.While the value of water saving potential is relatively low in Northwest China,the results of regional water stress index show this potential has the most significant benefits on available local water resource in these regions.Based on the main research results,this study emphasizes the importance of both locating large-scale PV projects reasonably and strengthening the construction of ultra-high voltage grid on the transmission side,further increase the cell efficicency and promote the intensive land occupation of large-scale PV projects.It is also suggested to take regional water resource as an important factor for the layout of the supply chain,and encourage the application of recycle technology for the retirement of PV plants.