Filenews 26 March 2023 - by By Christakis Hadjilaou*
The critical problems of the increased penetration of Renewable Energy Sources (RES) in the electricity system of Cyprus, which need to be addressed immediately, focus primarily on the frequent and extensive execution of renewable electricity cuts and the marginal operation of increased risk, which entails risks for causing serious problems in the safe and reliable operation of the electrical system. Then, an analysis of the critical problems of the increased RES penetration will be attempted, as well as the proposed solutions.
Extensive RES cuts
Based on up-to-date data and operating data of the Cyprus electricity system, renewable electricity cuts for safe operation purposes are an almost daily occurrence. It is noted in this regard that the annual production of renewable electricity, in percentage of the total annual electricity production, is currently around 18%. It goes without saying that the increase in this percentage for the coming years, without immediate measures, will be accompanied by even more frequent and far-reaching cuts.
For the seriousness of the situation, it is characteristically mentioned that the cuts in the penetration of large photovoltaic systems - for February 2023 - range on average, in percentage of the monthly electricity production of large photovoltaic systems, around 22%. This development is of concern and concern at the same time, as in the coming years the installation and operation of photovoltaic systems will continue at a rapid pace, which will make the problem of cuts even more serious. That is, it is no exaggeration to say that the electricity produced, for every new MW of photovoltaic power that will be installed in the next period, will be cut off to a large enough extent for the purpose of safe operation of the electrical system.
In connection with the above, it is noted that currently the cuts in RES penetration mainly concern large wind and photovoltaic systems, whose production is fully controlled by the Operators, without being disconnected from the electrical system. On the issue of the need for control of RES systems we had dealt more extensively in the context of a previous article.
Marginal operation of the increased risk electrical system
In addition to the serious problem of renewable electricity cuts, it is equally important to highlight the marginal operation of the electricity system, as a result of increased RES penetration, without storage and interconnection systems. In the case of marginal operation, the electrical system remains with a minimum number of conventional generating units in operation, which is considered strictly necessary to ensure the proper functioning of the electrical system. It is emphasized that the marginal operation of the electrical system is a critical situation of increased risk, which in the event of serious failures and / or large deviations in the forecast, can cause serious problems in the safe and reliable operation of the electrical system.
A typical example of marginal operation is the state of the electrical system on Saturday 18/3/2023. In the context of managing this marginal situation, TSOC, which apparently did not have readily available reserves to meet demand - due to a large discrepancy in the forecast of the production of RES systems - was obliged to carry out consumer load cuts for safety purposes of the electrical system. It goes without saying that the problem of marginal operation will be aggravated by the increase in RES penetration, which is expected in the coming years.
Solutions to address critical problems
The solutions proposed to address the critical problems of cuts and marginal operation of the electrical system, concern the immediate installation of new, small and flexible conventional production units at the Dhekelia Power Station, as has been presented in detail in the context of a previous article and the installation of a central renewable electricity storage system.
However, it is noted that the proposed solutions are expected to be implemented and operate within 2-3 years. Therefore, the critical problems of increased RES penetration will continue to exist during this period and will afflict the electricity system of Cyprus to a greater extent. In my technocratic view, the aforementioned critical problems have not been addressed in time by the competent bodies, with the result that the electrical system is already experiencing dangerous borderline situations and frequent and extensive cuts in renewable electricity are being carried out.
Installation of small and flexible conventional production units
The installation and operation of new, small and flexible conventional generation units at the Dhekelia Power Station, in addition to their financial advantages, will give the TSO the necessary flexibility for the effective management of the electricity system of Cyprus. Specifically, these units will be able to be connected and disconnected to cover peak periods of short duration, as well as for effective handling of possible fluctuations in RES production. In this way, they will significantly help prevent frequent connections and disconnections of base units, which causes great stress on these units, resulting in an increased need for frequent maintenance, as well as an increase in the frequency of failures.
Installation of a central storage system
The installation of a central electricity storage system will contribute to the absorption of excess renewable electricity, preventing cuts and the provision of ancillary services to enhance the security of the electricity system. It is emphasized that the operation of the central storage system will be able to supply readily available reserves to restore the proper functioning of the electrical system, in the event of borderline situations. Therefore, the immediate installation of a central electricity storage system for security purposes, could provide solutions to the critical problems that afflict the electrical system, as a result of the increased RES penetration.
Seriously considering that the central storage system should be installed as soon as possible, for the purposes of safety of the electrical system, it is an immediate need to study optimal ways to achieve this goal. Essentially, there are two options for dealing with the issue of installing the central storage system in the Cyprus electricity system, the implementation of which, in my estimation, will last at least 2-3 years.
The first option is within the Electricity Market, with appropriate regulation of the legal framework of the transitional regulation of the Electricity Market, to allow the installation and operation of storage systems upstream of the meter (a relevant revision of the Market Rules is already underway). The second option is outside the Electricity Market and includes the undertaking of the storage system by the TSO for the purpose of safe operation of the electrical system. The application of the second option is conditional on obtaining a derogation, as the ownership, development and management of storage systems by the TSO is not allowed in accordance with Article (62) of Directive (EU) 2019/944. However, it is raised for reflection, as an alternative, in case it is judged to be the fastest and most effective solution for timely addressing the issue of increasing and extensive cuts in RES penetration and the need for immediate strengthening of the security of the electrical system.
Concluding summary of the situation today
Based on what is mentioned in the above text, it is considered that the critical problems of the increased penetration of Renewable Energy Sources (RES) in the electricity system of Cyprus, which need to be addressed immediately, are mainly focused on the frequent and extensive execution of renewable electricity cuts and the marginal operation of increased risk, which entails risks for causing serious problems in the safe and reliable operation of the electrical system.
It is a primary necessity to take immediate and drastic measures that minimize renewable electricity cuts but at the same time promote the safe operation of the electricity system. In this regard, it is emphasized that, if immediate measures are not taken, the management of the electrical system will become increasingly difficult and complex. With the increased penetration of RES, the cuts will increase rapidly and the electrical system will experience even more often marginal situations of increased risk, as in the case of Saturday 18/3/2023 described above.
SUGGESTION
The urgent priorities
Therefore, a proposal is made to take bold decisions to immediately begin the installation of new, small and flexible production units at the Dhekelia Power Station, as well as the installation of a central storage system for the purpose of safe operation of the electrical system.
In the meantime and until the possible implementation of the proposed solutions, which should already be in place, the Cyprus Transmission System Operator (TSO) should find ways and take all appropriate measures for the safe management of RES penetration, in a way that prevents dangerous borderline situations for the electrical system.
* Electrical Engineer, with many years of experience in the operation of the electrical system
