Wind energy and the hydrogen economy—review of the technology

The hydrogen economy is an inevitable energy system of the future where the available energy sources (preferably the renewable ones) will be used to generate hydrogen and electricity as energy carriers, which are capable of satisfying all the energy needs of human civilization. The transition to a hydrogen economy may have already begun. This paper presents a review of hydrogen energy technologies, namely technologies for hydrogen production, storage, distribution, and utilization. Possibilities for utilization of wind energy to generate hydrogen are discussed in parallel with possibilities to use hydrogen to enhance wind power competitiveness.     

Catalyst degradation diagnostics of proton exchange membrane fuel cells using electrochemical impedance spectroscopy

A previously validated equivalent circuit model, in which two resonant circuits were inserted to represent the processes in the catalyst layers, is applied to fit the electrochemical impedance spectroscopy results of a single proton exchange membrane fuel cell exposed to accelerated stress test targeting catalyst degradation. The simulation results of the applied equivalent circuit model show very good agreement with the experimental data. The applied model is able to extract contributions of each of the model elements to the cell degradation. The obtained results indicate that the cathode catalyst layer resonant loop parameters, together with the cathode charge transfer resistance and cathode double-layer capacitance, change the most during the accelerated stress test. If each of the elements of the cathode resonant loop can be associated with physical processes inside the catalyst layer, the model may be used to give more insight into the degradation effects on functioning of the catalyst layer. From the conducted electrochemical impedance spectroscopy analysis, it seems that the low-frequency intercept in Nyquist plot shows the most significant change with degradation, so it may be used directly as a sufficient indicator of fuel cell performance degradation due to catalyst layer degradation.     

Techno-economic analysis of PEM fuel cells role in photovoltaic-based systems for the remote base stations

Expansion of telecommunication networks even to the most remote areas where connection to the utility grid could never be justified, especially in touristic regions, has led to the increasing need for stand-alone power systems. In Adriatic coastal area employment of hybrid photovoltaic-based systems is straightforward due to high sun potential. Inherent intermittent nature of renewable sources is especially not compatible with telecommunication system who require uninterrupted power supply. This leads to the need of not only energy storage, but also a “back up” solution in the case of primary system failure. Emphasis is put on the system reliability and simplicity while system price is not necessarily top priority. Usual approach of using diesel generators as a “back up” has been challenged by the introduction of PEM fuel cells. Even with hydrogen technologies market development still lagging behind some comparable advantages such as high energy conversion efficiency, silent operation and no emissions make PEM fuel cells a legitimate candidate for replacing traditional oil burning generators. Techno-economic analysis of various stand-alone power systems for the remote base station on an Adriatic island is made. At the moment, levelized cost of electricity point of view still gives slight advantage to the diesel generators. Though, uncertain petroleum market and fast developing hydrogen technology market could reverse this trend in the near future. Long term reliability of PEM fuel cells system still needs to be examined in practice, as this combined with pro-environmental characteristics of fuel cells can make the difference especially in pristine and protected areas.