The Cyprus transmission systems operator (TSO), on Tuesday clarified the reasons leading to power cuts over the weekend.
It is not always possible to make accurate minute-by-minute predictions in a mixed energy system relying on input from renewables, TSO Stavros Stavrinou told the CyBC.
“The job of the TSO is to balance the energy supply and demand,” Stavrinou explained, and to keep the system stable by juggling correct ratios of conventionally and renewably sourced (RES) energy.
On Saturday, Stavrinou explained, despite estimations made for a 24-hour period, a sudden thick cloud cover took the operators by surprise, necessitating the activation of fast-response units utilised as back-up when the demand load is too high.
The situation was compounded by the fact that this happened during a systems maintenance period and some of these units happen to be temporarily out of service. In addition, supply from wind farms was also low, the operator said.
The TSO downplayed concerns over the reliability of RES and rubbished claims that any kind of faltering had occurred.
“This was a very temporary short-lived stray from predicted outcomes and was handled in a timely way,” Stavrinou said, adding that the cuts lasted only 50 minutes whereafter the system was restored.
Later in the day the sun and wind returned bringing levels back to exactly what the operators had calculated, Stavrinou said.
The sudden drop in production from photovoltaics of over 100MW was an extreme outlier Stavrinou explained. “We were expecting 140MW and we got 20,” the operator detailed.
Stavrinou went on to express optimism in the system, saying that for half-hours at a time last year, Cyprus was powered at a level of up to 67 per cent from RES, and the annual RES input average last year was 17 per cent.
Stavrinou also clarified that the brief power cuts on Sunday had nothing to do with the ones on Saturday and were the result of brief losses of energy due to system faults.
“About eight or nine times yearly, there may be a fault in the system, and we experience small power cuts from that as units need to be briefly taken out for repair,” Stavrinou said.
The TSO added it was important to understand that fast-response conventional back-up units will be needed in any system in the foreseeable future and will not be done away with anytime soon. It is also the reason why the Dhekelia units need to be upgraded, as demanded by electricity authority union employees, Stavrinos said.
Storage would of course have prevented power cuts like the ones on Saturday, Stavrinou admitted, and the government is taking steps towards tenders for private investment in this part of the supply chain, supported by funds from the EU’s recovery and resilience plan.