Since March 2021, the Department of Industrial Electrical Power Conversion of the University of Malta, has carried out various studies on how to further increase the share of renewable energy sources integrated into the Maltese Electrical Network without affecting it negatively. This work was carried out during the two-year funded research project ESTELLE. The project has been funded by the Energy and Water Agency under the first call of the National Strategy for Research and Innovation in Energy and Water (2021-2030). A number of studies were carried out in collaboration with Enemalta plc and Olympus.
Advances in renewable energy generation technologies and their increased deployment are gradually changing the Electrical Network from centralized unidirectional systems into distributed bidirectional systems. The transition is causing a number of challenges including reverse electrical power flows and larger voltage fluctuations.
One way to mitigate these unwanted issues is through the deployment of utility scale and behind-the-meter battery energy storage systems (BESS). In addition to BESS, electricity may be used to generate other energy carriers, including synthetic gas and liquid fuels.
Power-to-X (PtX) is an umbrella term for various processes that turn electricity into heat, hydrogen or synthetic fuels. Power-to-gas and power-to-liquids technologies appear to be promising solutions to decarbonise the energy sector, in line with the development of low-carbon electricity generation capacities. The main objective of ESTELLE was to put forward new methods, models, and research tools to reduce barriers for the deployment of BESS and P2X technologies in Malta.
In ESTELLE, detailed network simulations have been carried out at different levels:
- Utility scale: Sizing strategy and simulations of the integration of large scale central storage applied to the Maltese electricity network.
- Community scale: Sizing strategy and simulations of the integration of community scale storage applied to the Maltese electricity network.
- Behind-the-meter scale: Domestic-scale BESS were distributed along points of the Maltese distribution network feeding the consumers/prosumers.
Storage will also alleviate the issues foreseen for the near future, when the number of electric vehicles (EVs) on the Maltese Islands will increase. The modelling has also shown that distributed storage systems, if properly controlled and maintained, will perform better than centralised storage. However, all three types of BESS scales should be promoted as they could provide benefits for all the relevant stakeholders.
Another study carried out in ESTELLE derived a method to determine rapidly the approximate storage system size required to balance out the reverse power flows due to PVs and periods of high loads including EVs. This methodology can be used by planners as the first step in estimating the size and cost of a battery based system.
During the project a demonstration of a smart residential-scale BESS was set-up inside the laboratories of the Department of Industrial Electrical Power Conversion of the Faculty of Engineering. This set-up was used to study the performance of such systems with typical domestic loads.
The principal investigator of the project is Dr Alexander Micallef while the rest of the UM team consists of co-investigator, Prof. Ing. Cyril Spiteri Staines and RSO: Lazar Dulović.
