Update on TALENT / December 2022
Since June 2022, the work within the TALENT project has progressed notably in all of its Work Packages. Here is a summary of what has been achieved since the last update.
TALENT project should have been finalized by the end of September 2022. However, an extension has been approved by the European Commission, allowing to continue the work until July 2023. This was needed since the Covid-19 pandemic generated delays that affected key developments of the project:
- The manufacturing of the iBatts, which are the basic units to build the batteries needed for the prototypes of the multi-homes (800V), district (1,500V) and utility (3,000V) use cases.
- The supply of power samples needed to build the utility converter (3,000V).
Fortunately, both issues could be satisfactorily solved and now the focus is on the validation and assessment of the impact.
WP2 and WP3, which deal with the development of the electronic architecture for the multi-homes and district use cases are finalized.
The process for the battery manufacturing starts with the verification of each cell. Electrical parameters, such as voltage and internal resistance, are tested to ensure the proper operation of the final iBatt module. Once all the cells are properly positioned, the laser welding process takes place. The next step is the insertion of the cells block into the battery box, where power and communication wires are connected. During this stage the BMS is also connected. Once everything is revised the battery is closed and connected to the DC/DC which is in a separate box. The final procedure is the FAT (Factory Acceptance Test) where load, unload, communications and balancing control are checked in order to ensure a proper behavior of the final product. When the FAT test is finished, the battery pack is packaged and delivered to the final destination.
WP4: High Voltage Battery Storage Systems
Work Package 4 concerns the prototyping of a medium voltage DC/AC power electronics building block (CEA) on which 8 li-ion batteries can be connected in series via 8 DC/DC converters (60kW each) (CEGASA). The DC/DC converters are made of GaN transistors operating at 200kHz allowing a high compactness of the intermediate AC stage. The iBatts have passed the isolation tests, and a special frame is being designed. 8 iBatts should be delivered to CEA in the very beginning of March 2023.
Once ANPC power stacks (3x500kW) equipped with SiC MOSFET 3.3kV and Si IGBT 3.3kV modules are received, they are equipped with water plates, gate drivers and DC capacitors. The three-phase LCL output filter is dimensioned for a switching frequency of 7kHz and has also been delivered. It will soon allow the implementation of an opposition method of two power stacks to assess losses. The first double pulse tests reveal switching energies allowing efficiency > 99% over the entire power range for a 7kHz switching frequency. These results will be confirmed by loss measurements by the opposition method in real conditions of operation. Simulations using the PLECS software are being lead to analyze the interaction between the 8 iBatts connected in series and the medium voltage DC/AC converter.
CEGASA Ibatt and CEA MV power stack
WP5, dealing with the development of the Management Software for Decentralized and Hybridized Energy Systems, is already finalized.
WP6: Validation in Relevant Environments
In Work Package 6, which deals with the validation in relevant environments, the validation works for the multi-homes and district cases have been finalized, while the validation for the utility case is under preparation. This one is extremely challenging, involving the manipulation of equipment under 3,000 V, so special safety measures must be accomplished. CEGASA and CEA are working hard to ensure a successful validation, while guaranteeing all needed safety measures.
- Validation of the multi-home use case: This validation has been done at the Lemur power lab facilities at the University of Oviedo. Different power conversion schemes and architectures were implemented 1) the iBatt concept serialized up to 800 Vdc, 2) the 3-level interlinking multi-port converter for the building-level connection to the AC grid, 3) the internal connection of PV generation and AC loads to the dc-link of the interlinking converter, considering the split-bus connection strategy already proposed in former deliverables in the TALENT project.
- Validation of the district use case: All the validation tests were performed and D6.3 was submitted some months ago. The main purpose of the three port power converter is to serve as an interface to the different sources: PV panels, battery and the electrical AC grid. The main electrical characteristics for the proposed three port power converter were depicted in D1.1, and they have been characterized in a real electrical test environment at nominal power. One of the main duties on this project was the test rig at 1500Vdc and full power. It has been a huge challenge in terms of size, equipment, and budget. Thanks to the modular concept given to the three port converter, a validation plan was proposed for just using the one single DC/AC module and one single DC/DC module instead of testing the whole system (one full DC/AC converter and up to 4 DC/DC modules to reach 4+2 MW in the PV port). Namely, a 2 MW DC/AC solution and a 0.5 MW DC/DC module have been tested. This solution has allowed to reduce the test bench requirements significantly, and just 3 power blocks are needed as shown in the next figure:
- About the tests performed: for the DC/AC converter all the electrical characteristics defined in D1.1 were met.
- Power level of 2MW
- Efficiency 98.8%
- Reasonable dynamic response in active power of 70ms (from o to Pnom)
- An outstanding current THD value of less than 1% was obtained
About the DC/DC stage, despite this converter being smaller than the AC/DC converter from an electrical and physical point of view, it has been a challenge for Gamesa Electric, since a power converter for battery chargers like this one, working with the DC/AC stage synchronized, had never been designed up to now.
All the electrical characteristics have been in line with the original specification set in D1.1. However, an important aspect to remark here is efficiency. For the DC/DC converter the maximum efficiency expected was 98.5%, however the maximum value obtained has been over 99.3%, that means almost 0.9% over the maximum defined in D1.1 for DC/DC converter.
- Validation of the utility use case: The medium voltage demonstrator (utility scale) is based on the operation of 8 iBatts connected in series designed at CEGASA associated with the medium voltage DC/AC converter prototyped at CEA. The demonstration safety was analyzed by the safety officer of CEA for approval. The internal structure and isolation of the iBatt has been exposed, and an experimental area for the implementation at CEA has been described including the required protection components. Simulations were also carried out by CEGASA to prove that in the event of accidental opening of the output contactor of one of the iBatts, the voltage did not evolve across the terminals of the switches towards destruction. Finally, a layout of the premises is provided in CEA's solar technologies department to allow experiments in safe conditions. The schedule is complicated due to component shortages and unpredictable hazards of the 8 iBatts. If it turns out that the delays are getting longer, an emergency plan will be launched for the demonstration in which the iBatts will be replaced by a high-voltage battery simulator made available by CEA.
Utility scale experiments
- Validation in La Plana pilot: The validation of the TALENT control architecture including the DHEMS and the VPP has been validated in two scenarios:
- Scenario 1 includes the VPP management software and two Local DHEMS units controlling two hybrid power facilities.
Scenario 1 architecture.
- Scenario 2 includes the VPP management software, a Cloud DHEMS and two Local DHEMS units controlling two hybrid power facilities.
Scenario 2 architecture.
Scenario 1 is focused on not only validating the local control of the facility but also the VPP control of several power venues, while the Scenario 2 is focused in testing the Cloud DHEMS as a technical aggregator for hybrid plants connected to the VPP. Several validation tests have been already carried out successfully and the deliverable D6.5 is in progress. D6.5 will demonstrate the behavior of real hybrid plants controlled by the VPP remotely, showing the accuracy and time response.
WP7: Cost Assessment and Exploitation Strategy
All tasks in this WP are ongoing:
- Task 7.1: Cost benefit analysis of the proposed TALENT solutions: A calculation model has been developed to analyze the input data from previous Work Packages in economic terms. The cost-benefit assessment is based on the CAPEX and OPEX, and the revenues and/or savings estimated. A calculation tool has been designed to carry out these cost-benefit analyses for the TALENT solutions. This business model calculation tool has been developed to perform the simulation of batteries in different scenarios. The results of the rest of the Tasks will be used to feed the tool and to obtain the results of the cost-benefit analyses for TALENT.
- Task 7.2: Evaluation of the impacts of TALENT technologies for the multi-homes and utility use cases on the grid operation is now finalized. The district case will follow next. Interesting results have been achieved during the investigation of the multi-home and utility TALENT solution connection into a standard distribution utility network. In this regard, the capabilities of the TALENT solutions, which are proposed for the multi-homes and the utility area, are investigated through different electrical studies including load flow, short circuit, power losses analyses under various network configurations and conditions. In addition, the dynamic response of the TALENT technology to frequency and voltage changes as well as short-circuit faults are analyzed through time-domain simulations to evaluate effectiveness of the TALENT solution to improve network stability.
- Task 7.3: Assessment of the environmental performance of TALENT solutions as compared against standard ones, with a specific reference to End-of-Life management and focus on Rare Earth Use in electronics. The methodology being used is the well-known Life Cycle Assessment. Task 7.3 deals with a comparative life cycle assessment (LCA) of standard and TALENT configurations, for the manufacturing phase of each electrical component, in the 3 demo cases under analysis. The LCA of standard configurations has been conducted on the 3 demo cases (namely Multi-home, District and Utility scale), including the evaluation of rare-earths use. The TALENT setup for Utility has already been evaluated through LCA and compared with standard setup, with positive results due to a better use and management of raw materials: detailed results and evidences of this comparison are object of a paper in phase of drafting, thanks to a proficient collaboration with the Utility demo partner, i.e. CEA. The data collection about the manufacturing of multi-home and District TALENT setups is on-going with related technical partners and, in the upcoming months, also LCA on these configurations and proper comparison with their standard benchmarks will be performed as well.