Techno-economic potential evaluation of small-scale grid-connected renewable power systems in China

With the issues of energy shortage and environmental pollution becoming more and more serious, renewable power generation system plays an important role in energy conservation and emission reduction. The widespread application of renewable power systems meets the requirements of current developments in China. The development of renewable power systems is still faced with a certain degree of economic and policy obstacles such as high costs and ossified subsidy, etc. China's vast territory also determines that different regions have different objective development conditions, these uncertainties are not conducive to the development of renewable power systems. In this paper, 20 cities in five typical climate zones in China were selected. In consideration of climate and electricity tariff, the technical, economic and environmental performances of three types of the community-level grid-connected renewable power prototypes are compared by a full-year simulation, including basic photovoltaic power system, wind turbine system and biogas power system. Then, a comprehensive evaluation index is developed to evaluate the energy systems potential, which integrates all the technical, economic and environmental performance indicators. The advantages and disadvantages of renewable power system development in different regions were analyzed, to provide reference for China's green development and policy-making.It is found that biogas power system has comprehensive advantages in costs and electricity production for most cities,as the comprehensive evaluation index of BG in most cities is higher than that of PV and WT. In contrast, photovoltaic power system is not an economic option for the majority of cities, except several cities where are rich in solar energy resources, such as Lhasa and Sanya.The comprehensive evaluation index of the photovoltaic system in Lhasa is 0.45, which is only lower than the wind power system in Shanghai among the 60 systems. In the southeast coastal cities with high average annual wind speed, such as Shanghai and Shenzhen, the wind power system has great potential for development. The comprehensive evaluation index of Shanghai wind power system is 0.489, which is the highest. The sensitivity analysis included in this study shows that the local grid purchase tariffs have greater impacts on systems lifetime costs than feed-in tariffs.The reduction of local grid purchase tariffs and the increase of feed-in tariffs are beneficial to the development of renewable power system.