Large Scale Distributed Fuel Cell Systems for Peak Shaving (LSD)
The vision of the project is to develop fuel cell (FC) technology, which is suitable for fitting into larger scale peak shaving systems in relation to wind mills and SMART grid applications. The technology should be integrated with localized power/heat production in order to utilize the heat from the FC (and electrolysis – although electrolysis is not a part of this project). Increased electrical efficiency will be obtained by the utilization of the oxygen from the electrolyzer, which is normally wasted, as well as by general improvement of the cells. Besides, the overall energy efficiency will also be improved by utilization of the produced heat in the district heating system. The latter is facilitated by high working temperature of the high temperature PEM fuel cell (i.e. 140-160 ̊C). There are a number of ongoing projects in Denmark (and internationally) for the development of efficient electrolyzers suitable for large scale hydrogen production. However, efficient utilization of the produced hydrogen and oxygen is lacking. This is addressed in the proposed project.
When fuel cells and electrolyzers are in place the question arises whether large scale storage of hydrogen and oxygen can be carried out in a safer manner than in the state of art high pressure tanks. This is addressed in parallel to the fuel cell development by an early investigation of a new storage concept recently conceived by SP Group and FiBaC – now with a patent pending. The idea is that the risk of explosion might be reduced significantly if hydrogen is stored in combination with supercritical CO2.
The CO2 will be added only once and be recycled in the system. In order for this to be possible when hydrogen is consumed an efficient separation technology is mandatory. Fortunately, experimental studies at SDU have shown that such a separation can be carried out with a minimum pressure drop by using of special materials with tailored pores developed at SDU.
In summary, the project thus comprises the following key points:
- Development and testing of large area pressurized fuel cells for large scale systems
- Improvement of the fuel cell technology for performance and lifetime
- Investigation of the effect of enrichment of the cathode air by pure oxygen.
- Collection of the experimental data for optimization of gas storage in supercritical CO2
- Optimization and further verification of the highly efficient gas separation materials developed at SDU.
- Construction of gas separation membranes for test system
- Development of monitoring and control system for CO2 recirculation.
Future added values of the CO2 coupled storage and the separation technique could be a new way of introducing hydrogen to the natural gas grid, namely in combination with CO2. In this way the combustion properties can be adjusted to be more like natural gas and the energy required to synthesize methane is saved. Finally, efficient gas separation techniques will find numerous other applications.