1. Department of Energy and Power Engineering, Tsinghua University, Beijing, P. R. China
2. State Grid (Beijing) Integrated Energy Planning and D & R Institute Co., Ltd, Beijing, P. R. China
3. Shanxi Gemeng US-China Clean Energy R&D Center Co., Ltd, Taiyuan, P. R. China
4. Shanxi Research Institute for Clean Energy, Tsinghua University, Taiyuan, P. R. China