Filenews 21 March 2023 - by Chrysanthou Manoli
The gap between production and demand was unusually large
There were a few reasons to... stay out of power for a few minutes on the rainy Saturday morning and need the Cyprus Transmission System Operator (TSO) to take turns disconnecting thousands of consumers from the grid, for about 15 minutes each. The problem was fully managed within about an hour (09:37 to 10:31), but there was dissatisfaction from affected consumers and concern about the inadequate planning that was done competently, for a day when the Meteorological Service had predicted rains and local thunderstorms.
The announcement issued by the Transmission System Operator referred to a major failure in the forecast of production from renewable energy sources at that time. However, in the case of the photovoltaics they produce for the grid, the Distribution System Operator, i.e. EAC Distribution, which uses, among other things, the services of a company specializing in forecasting production and demand, in combination with weather conditions, is responsible for the initial forecast of their production.
But the forecast for Saturday morning fell too far out. Our information indicates that at some moments the discrepancy between the forecast and the actual production from photovoltaics reached or even exceeded 120 megawatts, which is very unusual, hence the report of the TSO to a major failure. The final decision on the commitment of contractual units (EAC) for the next day's production is made by the Transmission Operator, which has the option to vary accordingly the forecast received from the Distribution Operator. It seems that such a differentiation was made for Saturday, but it was not enough to make up for the big difference that arose.
However, there was another reason why the reduced, due to weather conditions, electricity production from RES was not covered in time by the EAC units and it took a few minutes, at least, interruptions in the electricity supply. The reason was, as we are informed, the inability of EAC to activate all the fast operating units at its disposal, in order to immediately fill the gap between electricity generation and demand. For example, the six Internal Combustion Plants (ICEs) in Dhekelia, which are one of the most flexible and fast-responding EAC units, were not immediately available, due to maintenance or other work in progress. In addition, there was damage to a gas turbine in Vasilikos, which could otherwise be quickly put into operation and prevent the need for power cuts. Very essential for the system was the help offered by the 4 gas turbines in the Monastery, which were activated rapidly.
Meeting at CERA
In order to examine the reasons why the forecast of EAC Distribution and ultimately of the Transmission Operator for the production of photovoltaics in an expected rainy day fell so much out, as well as the reasons why the gap could not be filled in time with electricity from EAC units, a meeting was held yesterday at CERA, in the presence of all those responsible. The parties explained their positions on the incident, but reserved the right to file them in writing. The spring and autumn period are considered to be one of the most difficult for load management, as it requires, for the safety of the system, the continuous production by conventional EAC units for a significant part of the energy needed and on the other hand, the utilization of production from RES has priority by law. Therefore, a sure solution of committing as much conventional energy as possible (at the expense of RES) is generally avoided.
