Filenews 28 January 2023 - by By Christakis Hadjilaou*
The electrical system of Cyprus is small and isolated and in no way should it be compared with the interconnected systems of other countries, as these are dissimilar situations, which may lead to erroneous conclusions.
It is characteristically noted that the installed capacity of the conventional units of the system amounts to only 1478 MW, which is scattered in the Power Stations (HS) of Vasilikos, Dhekelia and Moni. ES Vasilikos has 868 MW of installed conventional production (three steam turbines -3X130MW-, two combined cycle units -2X220MW- and one open cycle gas turbine -1X37.5MW-), ES Dhekelia 460 MW (six steam turbines -6X60 MW- and two MEK arrays -2X50 MW-) and ES Moni 150 MW (four gas turbines -4X37.5 MW-).
In this regard, it is emphasized that the way of safe operation of the electrical system in relation to the installed conventional capacity (i.e. in relation to the continuous operation of units of one or two HS) is crucial for the secure supply of electricity to the consumer.
Then, a brief analysis and evaluation of the operating methods of the conventional electricity production system will be attempted, in order to study the optimal mode of operation to ensure the secure supply of electricity to the Cypriot consumer.
2. Power supply of the electrical system from the stations of Vasilikos and Dhekelia
Taking into account the current state of affairs, it is pointed out that, in the context of safe operation, the electrical system should be supplied with electricity from a number of base units in ES Vasilikos and ES Dhekelia. The gas turbines (costly quick-start units) of the Monastery are used as reserves to cover peaks in electricity demand and possible failure of production units.
In this regard, it is noted that the continuous operation of a number of production units, at least in two HS, contributes to the increase of the security of supply of electricity to the consumer, since in case of loss of one plant, due to serious damage, sabotage, natural or other disasters, the probability of causing total extinguishing of the electrical system is greatly reduced.
In connection with the above, it is stated that the recent past, with the explosion in Mari and the destruction of the ES Vasilikos in 2011, proves that the presence of ES Dhekelia has prevented the total extinguishing of the system, which would have chaotic implications for the economy of the Republic of Cyprus.
3. Supply of electrical system from the area of ES Vasilikos
The plans of the competent bodies for the arrival and utilization of natural gas for power generation purposes, which according to press reports concerned the area of Vasilikos, had probably taxied the almost exclusive supply of the electrical system from the area of HS Vasilikos. In order to implement these plans, the entire conventional production capacity of the Cyprus electricity system should be concentrated in the area of HS Vasilikos.
It is noted in this regard that all prospective conventional producers for connection to the electrical system have been licensed by CERA in the area of ES Vasilikos.
However, the plans of the competent bodies for the optimal utilization of natural gas, which is conditional on the concentration of conventional production capacity in the area of Vasilikos, cannot currently be implemented, due to the inability of the competent bodies to connect additional conventional production to the electrical system.
The additional conventional production in the area of Vasilikos should have replaced the six steam turbines of TH Dhekelia, which in early 2022 should have been taken out of service, in order to comply with the emission limits for pollutants. Therefore, in order to ensure adequacy in production in the coming years, at least until the connection of additional conventional units, there is no other option than to continue the operation of the aging, costly and polluting steam turbines of TH Dhekelia, for which the Republic of Cyprus has requested from the European Commission an extension of operation until 2028.
As a result of this development, the electrical system cannot currently - for reasons of adequacy in production - operate with the exclusive feeder of ES Vasilikos. According to information that has recently seen the light of publicity, it is pointed out in this regard that for the safe transition to the operation of the electrical system with almost exclusive supply from the area of ES Vasilikos, in addition to the problems of adequacy in production, there are also technical problems, the solution of which requires an upgrade of the transmission system.
In connection with the above, it is noted that in order to decide on the operation of the electrical system with almost exclusive supply from the area of Vasilikos HS, it is necessary to carry out a series of studies (eg environmental study, cost-benefit study, techno-economic study). These studies should clearly demonstrate the relevance of this exercise, as well as the conditions required for its implementation.
4. Assessment of operating modes
The operation of the electrical system with exclusive supply from the area of ES Vasilikos, i.e. the entire conventional production capacity to be concentrated in the area of an HS, offers a significant economic advantage in the case of the arrival of natural gas, since there will be no need for costly transportation and management at another geographical point.
On the other hand, however, the safe transmission of electricity, from one geographical point only, to the entire electrical system is likely to require a significant upgrade of the transmission system. In connection with these positions, it should not be overlooked that the previous design of the electrical lines and transmission substations, at least up to a certain point in time, probably took into account that the Dhekelia ES would remain further in operation and the electrical system would be operated with at least two stations.
This position is also reinforced by the fact that the most powerful line of the transmission system (Dhekelia - Athalassa) was designed to originate from the transmission substation of TH Dhekelia. In this regard, it is noted that the design and operation of transmission system facilities is a complex, laborious and long-term process, which is formed according to the current data in the framework of the Ten-Year Transmission System Development Plan, prepared by the TSO and approved by CERA.
In conclusion, however, it is emphasized that the operation of the electrical system with exclusive power supply from the area of TH Vasilikos increases the likelihood of causing total quenching of the electrical system and endangers the security of supply.
Conclusions, comments and suggestions
Taking into account the inability of the competent bodies to connect additional conventional generation to the electrical system, there is no other option - to ensure satisfactory adequacy in production - than the forced continuation of the operation of the aging, costly and polluting steam turbines of TH Dhekelia.
Therefore, any plans for the operation of the electrical system with exclusive supply and utilization of the arrival of natural gas only in the area of HS Vasilikos cannot currently be implemented.
In this regard, it is emphasized that, in our technocratic opinion, the continuous operation of a number of production units in at least two power stations (as is necessarily the case today with the operation of the Vasilikos and Dhekelia HS), contributes to the increase of the security of electricity supply.
Therefore, in order to maintain Dhekelia ES as the second concentration point of conventional production, a suggestion is submitted for reflection to take actions, if they have not already been done, for the transmission and utilization of natural gas in Dhekelia ES as well.
* Electrical Engineer, with many years of experience in the operation of the electrical system
