Study On Virtual Water Flows And Impact Factors Of Carbon Emissions In Electric Power System

Since the reform and opening up, China’s economic and social develop rapidly, making a series of remarkable brilliant achievements. Especially power sector, as national infrastructure industry, has grown at least 20 times in the past thirty years. However, due to inefficient use of energy, technical conditions backward, weak awareness of sustainable development and other factors, China’s electric power system in the rapid development consumes a lot of resources and causes great damage to the environment, in which water consumption and carbon dioxide emissions are the main parts.China’s water resource per capita is only a quarter of the world average, facing severe water shortage condition. In addition, the greenhouse effect increased year by year, while China’s carbon dioxide emissions rank first in the world, thus China is facing enormous pressure from the world to decrease the carbon dioxide emissions. Power system as the main consumer of water and the major emitter of carbon dioxide, plays the most important role in solving the water shortage as well as the problem of carbon dioxide emissions.Firstly, this paper proposes a quantification method of virtual water flows within power systems. The proposed method fully considers the power transmission among different grids in China. Based on the proposed method, virtual water network diagram of China’s electric power system is drawn, quantitatively analyzing the virtual water flows and consumption within China’s electric power system.After that, we mine the in-depth information on the virtual water network of China’s electric power system during 2007-2012 based on the ecological network method, including virtual water trace analysis, grid importance analysis, and overall evaluation of the virtual water network. The results show that:1) during 2007-2012, northern grid and central grid always had the biggest output-orient importance and the biggest input-orient importance, respectively.2) During 2007-2012, the virtual water flows within China’s electric power system has a positive impact on China’s water shortage problem, and this impact is gradually accelerating enhanced; virtual water connection between central grid and eastern grid has been found to be the main source of this positive impact.In addition, carbon dioxide emissions accounting model considering power transmission is constructed with power transmission matrix as the core. Based on the proposed model, driving factors affecting carbon dioxide emissions of China’s electric power system are analyzed through factor decomposition method. The results show:1) electricity consumption is the main factor leading to the positive part of carbon dioxide emission increment of China’s electric power system during 2007-2012, accounting for 96.2% of the positive part.2) thermal power proportion and generation technology are the main factors leading to the negative part of carbon dioxide emission increment of China’s electric power system during 2007-2012.3) the carbon dioxide emission increment of China’s electric power system during 2007-2012 is mainly located in the eastern grid and central grid, accounting for 64%.