Tashlyk HPSPP: a year of service in balancing energy market
March 13 marks one year since Tashlyk Hydro Pumped Storage Power Plant, which is part of the South-Ukraine Power Complex, was brought to the balancing energy market* for the first time.
The first application for power system unloading by switching on the Tashlyk HPSPP in the power consumption mode (pumping or motoring mode) was accepted ** on March 13, 2020, and the first application for loading the power system (operation of the Tashlyk HPSPP in generator or turbining mode) – two days later, on March 15, 2020.
Since then, the Hydro Pumped Storage Power Plant is brought to the balancing market 3-5 times a week depending on the season, the state of the power system, the ability to submit applications based on the results of electricity sales in other market segments.
«This process is initiated by the application of the separated subdivision of NNEGC «Energoatom-Trading», - Mark Arabadzhi, the head of SUNPP commercial dispatching department explained. - «Its specialists analyze the market conditions, forecast the electricity shortage or surplus in the system and form an application based on their experience: indicate the mode – generator or pumping, the amount of supply or extraction of electricity, time period along with price for the service. In the next stage, upon analyzing all the received applications of energy market participants and ranking them under the price, the NPC Ukrenergo transmission system operator accepts the most advantageous offers. » If Tashlyk HPSPP is chosen, its operational commissioning (it takes 6-10 minutes) takes place under the command of the Ukrenergo dispatcher.
«Upon entrance to the balancing market, the HPP-HPSPP Cascade operating mode has changed. Now it operates in generator and pumping modes not only in the evening and morning peaks, but also during the day. It entirely depends on the market conditions and the season. Thus, in summer season, when there is too much electricity, on weekends HPSPP hydraulic units remain on standby, while during the winter peak we operate 4 cycles per day – twice in pumping mode and twice in generator mode,» Serhiy Muzychenko, the chief engineer of the HPP-HPSPP Cascade said.
«The time intervals of hydraulic units operation have also changed,» adds Oleksandr Melnychuk, the head of the Cascade's operative dispatching service. «Now they can be different – from 15 minutes to 4 hours. The work has become more intensive, because at any moment a command can be received for loading or unloading. Both equipment and personnel must be on full alert at all times, and it places additional responsibilities on operating and maintenance personnel. We are learning. We are working by new rules. We understand that it is the Hydro Pumped Storage Power Plant which is designed to operate in such mode. »
Oleksandrivska hydro power plant which is the second component of the HPP-HPSPP Cascade of the South-Ukraine Power Complex is also the participant of the balancing energy market. HPP applications for loading are usually accepted during periods of evening and morning peaks in the system. The energy yield ability is directly related to the allowed and current reservoir levels. The volumes of OHPP applications are small – from 2 to 9 MWh, the price is different: mostly it is close to the balancing market price limit – more than 1413 UAH per MWh at night and during the late evening (23:00 - 07:00) and more than 2355 UAH per MWh – at other times of the day. And when unloading the power system, the price can now start with at least 1 kopeck per MWh, as since March 1, 2021, the obligation for market participants to indicate the price in their applications at least 55% of the day-ahead market price has been cancelled.
Specialists of the commercial dispatching department are responsible for the technical aspect of the process, namely short-term planning of electricity supply, monitoring of power plant unit load, interaction with the NPP shift supervisor and Energoatom-Trading commercial dispatcher to adjust the actual electricity supply.
*The balancing electricity market operates on-line and strikes a production and consumption balance along with financial settlement of electricity imbalances. ** Accept means consent to pay.
Tashlyk HPSPP and Oleksandrivska HPP are parts of the South-Ukraine Power Complex, which is the only enterprise in Ukraine with integrated use of basic nuclear capacities along with maneuverable hydro- and hydro-storage capacities. Currently, 3 nuclear power units of the South-Ukraine NPP with a total installed capacity of 3,000 MW, 2 hydraulic units of Oleksandrivska HPP with a total capacity of 9.8 MW and 2 hydraulic units of the Tashlyk HPSPP with a total operating capacity of 320 MW in generator mode are in operation.
The construction of the HPSPP is under way. It is scheduled to put another three THPSPP hydro units into operation, so there will be 6 of them with a total capacity of 906 MW in turbining mode and 1299 MW in pumping mode.