题目：Efficiency Issues of Hydrogen Energy Technologies
Qingfeng Li, dr. techn. professor in Department of Energy Conversion and Storage, Technical University of Denmark, received his PhD at Northeastern University of Shenyang, China in 1990. He initialized the HT-PEM research in Denmark and has coordinated/participated 7 EU and 25 Nordic research projects including a 4M Centre devoted to fundamental research om mechanism, materials, manufacturing and management of HT-PEMFCs. Professor Li has been involved in teaching 5 undergraduate courses and 6 graduate courses and supervised 19 ph.d. and more than 30 master students.
Utilising electricity from renewable sources e.g. windmills or solar panels requires a certain back-up generating capacity. For a stand-alone power system utilising any kinds of renewable energies, the challenge is an effective energy storage technology at different time scales. Hydrogen, with a potential to provide a reliable, secure, and clean approach of energy storage, has been recognized as a practical scenario in the future renewable energy systems. The talk will start with a brief review of renewable energy status and challenges in Nordic countries, particularly the two key linking technologies in the renewable energy power chain i.e. the hydrogen generator (water electrolyser) and converter (fuel cells). More focus is placed on the energy efficiency which is a both thermodynamic and engineering issue. The issue is viewed through the entire hydrogen value chain including production, storage and conversion. High-temperature polymer fuel cells, as an example, will be investigated in term of a system efficiency including integration of fuel processing and heat recycling units. Finally recent progress and perspectives of the technologies will be discussed.