Laboratory scale hybrid hydrogen micro-grid systems

December 7th, 2022

R&D Focus Areas:
Technology integration process improvement, Whole supply chain, Energy systems integration

Lead Organisation:
Queensland University of Technology (QUT)

Partners:
Swinburne University of Technology, Deakin University, Future Energy Exports CRC, Australian Renewable Energy Agency (ARENA)

Status:
Active

Start date:
September 2019

Completion date:
Estimated December 2026

Key contacts:
Lead Investigator: Associate Professor Dezso Sera – Dezso.Sera@qut.edu.au
Laboratory Manager: Navin Bhardwaj

Funding:
Cash: AUD$329,000 (combination of QUT, Australian Government and contract funds)
In-kind contribution: AUD$393,000, Cash (for upgrade): AUD$100,000

Project total cost:
AUD$812,000 (combined cash and in-kind)

Project summary description:
This project is a laboratory scale hybrid hydrogen micro-grid system with associated technologies and practices. The system consists of: PV panel emulator, lithium-ion battery, maximum power point tracker (MPPT), multiple electrolysers (alkaline and PEM) and fuel cell (PEM).

The PV emulator supplies power to a 360W MPPT battery charge controller that ensures a 12V, 60Ah Lithium-Ion battery is charged in an optimal manner without being over- or under-charged. The charge controller also services an inverter supplied AC powered 300W PEM or alkaline electrolyser. Two additional grid connected electrolysers of similar power rating can be connected with produced hydrogen distributed to a gas panel housed within an actively ventilated fume hood.

The gas panel houses hydrogen storage (at 4bar) with various instrumentation supplying hydrogen to a 150W PEM fuel cell that can be optionally configured to either charge a 12V battery or emulate regenerated power export to the grid through a DC load emulator. This hybrid power and hydrogen microgrid mirrors the H2Xport pilot plant located at Redlands and can be used as the test bed prior to translating learnings to the larger pilot plant at ~50kW scale.

The microgrid enables testing of the concept Adaptive Renewable Energy Plant at a laboratory scale. The microgrid was developed as a lab-scale model for studying the production and consumption of green hydrogen. Current research is focussed on:

  • Improving the overall solar-to-hydrogen efficiency,
  • Reducing the cost of generated green hydrogen, and
  • Improving the microgrid stability and reliability.

Energy flow through the microgrid is managed through several feedback control loops that are programmed to prioritise energy storage, export or consumption based on an algorithm that seeks to minimise the cost of hydrogen while delivering a minimum committed volume on a daily basis.

This project progressed slowly in 2019-2021 due to requirements related to laboratory space access, reconfiguration/refurbishment of laboratory services and installation of appropriate safety procedures. Procurement of equipment and related resources occurred in 2020-21.

Since that time, the complete system (in minimal viable configuration) has been commissioned and utilised for ongoing HDR student projects including:

  • Construction or modification of AC and/or DC functionality for system components,
  • Impact of power converters on the degradation of the electrolysers,
  • Evaluation of equipment performance with relation to nominal specifications,
  • Renewable energy management and process engineering related to dynamic behaviour impact on battery and electrolyser performance and lifetimes,
  • Integration of novel materials for water electrolysis such as membranes and electrodes and new electrolyser stack designs,
  • Integration of water treatment solutions and impact studies of water purity on water electrolysis performance,
  • Development of control algorithms, and
  • Digital models for continued analysis of system performance. The digital twin developed in this laboratory will link with the Redlands hydrogen pilot plant and with a similar laboratory at SUT.

Lessons/Insights from research

Electrolyser stack degradation: PEM Electrolyser stress testing has been conducted by periodically switching on and off electrolysers for up to 500 hours and subsequently testing the stacks for degradation. Catalyst characterization has also been undertaken to assess the mechanism for degradation. In future, these studies can be further extended to larger stacks to determine the cause and potential mitigations for stack degradation.

Fuel cell degradation: Long periods of disuse can cause real and permanent degradation. This was noted when the 150W fuel cell was commissioned and tested almost two years after it was procured for the project. While some of the performance loss was recoverable with continuous testing and humidification of the PEM membrane, a 20% loss was, nevertheless, noted to be permanent and irrecoverable.

Deploying emulators: Solar PV and battery emulators were tested successfully in conjunction with electrolysers and fuel cell. This success has helped validate the strategy of using emulators for the microgrid in a lab setting. It allows for electrolysers and fuel cells to be tested across a range of power requirements without having to upgrade the system substantially. This innovative approach has also set up the microgrid for testing different operation and control algorithms for electrolysers.

Testing Kw rated electrolysers: Higher rated electrolysers (up to 2.4kW) has been successfully attempted in this microgrid setting. However, the DC section of the microgrid is limited in terms of its power rating and will, therefore, require an upgrade for longer term testing.

Effect of Single phase power supply: A single phase AC power input from an emulated Solar PV supply results in perturbations and sinusoidal variations in the DC supply circuit prior to the inverter. Although no obvious negative impacts have been noted on the battery or any other DC components so far, a longer duration study may be needed to fully understand the impact.

Local Repair/maintenance support: Fuel cells and electrolysers used on this project were mainly imported and have very little maintenance support. Obsolescence is the other issue that this type of research has to deal with. Fuel cells can be rendered obsolete fairly soon if no backward compatibility is available for the upgraded control circuits. Electrolysers are less prone to obsolescence but local support for repairs is still an issue. Equipment like PV emulators also have to be sent overseas for any urgent repairs and this slows down the pace of research considerably.

Hydrogen Storage capacity: Limited hydrogen storage capacity in this laboratory was identified as a key barrier to testing higher rated electrolysers and fuel cells. Safety considerations did not permit hydrogen storage to be scaled up. The decision to relocate the laboratory to another location was, therefore, taken to move the microgrid to another location that is better equipped to manage larger capacity gas storage.

Fuel cell testing with different electrical loads: Multiple DC loads have been coupled and tested with the 150W fuel cell for extended durations to demonstrate the capability of the hydrogen hybrid energy microgrid as a test bench for different fuel cell applications. The loads have included a relatively simple and steady DC load, a turbine motor and a robot prime mover. The limited capacity of the fuel cell at 150W limits the testing of larger electrical loads. An upgrade to a higher capacity fuel cell is planned for the new lab upgrade project.

Future plans

An alternative site has been identified for upgrading and relocating the microgrid. The microgrid is being re-designed for higher energy and hydrogen throughput capacity. Key equipment will be replaced. Safety considerations are paramount in selecting equipment and designing procedures to ensure future research objectives can be met safely.

The upgrade is estimated to cost an extra AUD$100,000 and six months to implement. It will target a power supply capacity increase to 40kW. A 200NL (30bar) compressed hydrogen storage capacity located in safe zone, 1kW fuel cell and 2.4 KW electrolyser, process safety interlocks and deployment of new design AC/DC converters are some of the additional capacity upgrades that are currently planned.

In addition to the above the capacity to implement control algorithms with re-designed AC/DC converters will also be incorporated in the upgraded microgrid.

Related publications and key links:
Boulaire, J. Love, I.D.R. Mackinnon “An adaptive renewable energy Plant (AREP)-To power local premises and vehicles with 100% renewables” Energy Strategy Reviews 38, 100703, 1-12, 2021.

  1. V. Patel, S. A. Gorji, S. S. M. Shahi and J. G. Love, “Implementation of a Lab-Scale Green Hydrogen Production System with Solar PV Emulator and Energy Storage System”,
    Presented at 11th International Conference on Power and Energy Systems (ICPES), pp. 201-208, 2021. doi: 10.1109/ICPES53652.2021.9683797.

Bhardwaj, J. Love, S. Gorji, A. O’Mullane, “Scaling electrochemical energy conversion materials for renewable hydrogen energy production”. Presented at Royal Australian Chemical Institute (RACI) National Congress 2022, Brisbane Convention & Exhibition Centre, pp. 3–8, July 2022.

  1. Gorji, “Reconfigurable Quadratic Converters for Electrolyzers Utilized in DC Microgrids,” in IEEE Access, Vol. 10, pp. 109677-109687, 2022. doi:
    10.1109/ACCESS.2022.3214581.
  2. Gorji and H. Gholizadeh, “A Modified Positive Output Super-Lift Luo DC-DC Converter with Improved Voltage Boost Ability,” 2022 5th International Conference on Renewable Energy and Power Engineering (REPE), 282-286, 2022. doi: 10.1109/REPE55559.2022.9949453.

Hakemi, S. A. Gorji, D. Sera, J. Walker, “DZ-Source Converter: A Duality Inspiration of Z-Source Converter for Current-Source High-Conversion Ratio Applications” IEEE ECCE 2022 (USA-Detroit), October 2022.

Ganjavi, S. Gorji, A. Hakemi, A. Moradi, D. Sera, “Design and Implementation of an SiC-based 48 V-380 V Dual Active Bridge DC-DC Converter for Batteries Employed in Green Hydrogen Microgrids” IEEE SPEC 2022 (Fiji), December 2022.

Moradi, S. Gorji, A. Hakemi, A. Ganjavi, D. Sera, “Study of a DC Micro-Gird Configuration to Produce Hydrogen (DCMG-H2)”, 2022 IEEE 7th Southern Power Electronics Conference (SPEC), Nadi, Fiji, 2022, pp. 1-5, doi: 10.1109/SPEC55080.2022.10058435.

Higher degree studies supported:
Six higher degree students currently supported.
Three research fellows/associates currently supported.
Seven higher degree students and four research fellows previously supported by facilities.

 

Updated: June 2024