If the hydrology is worse than planned, the missing quantities will definitely have to be compensated, so if there is not enough capacity from other sources, then the import of electricity must be resorted to, says Željko Marković.
The unusual pictures of bathers on the part of the Danube near Novi Sad, whose width in one part has almost halved due to the drought, so instead of swimming, many walk in this part of the river, are the result not only of several weeks of drought with only a few drops of rain, but also of the tropical wave “Lucifer”, which swept over Serbia and heated the air up to 43 degrees Celsius in recent days. This further aggravated the already difficult electricity situation in Serbia, caused by the global energy crisis, which is why “Elektroprivreda Srbije” has been importing both electricity and coal for months, covering both daily consumption and preparing for the upcoming severe winter.
However, what to do when the water levels of the rivers are the lowest in the last 10 years, and there are still two months until the end of summer? Electricity is getting more expensive. It is sold on the stock market for around 540 euros per megawatt-hour, “and we in Serbia charge 14 times less for electricity than in Europe”, said Aleksandar Vučić, the country’s president, commenting on the latest increase in the price of electricity from September 1 by 6.5 percent without of VAT.
Bearing in mind that about 30 percent of electricity is produced from hydroelectric power plants, it is clear that hydrology significantly affects the production and fulfillment of the balance sheet of “Elektroprivreda Srbije”. Any lack of capacity in production can threaten the stability of the power system, especially in a situation of power shortage, including in cases where due to extreme drought we have a significant reduction in the availability of hydro capacity, says Željko Marković, an energy consultant at “Diloit” in an interview with “Politika”, one of the long-term former directors of “Elektroprivreda Srbije”.
How much does drought affect the production of electricity, can it threaten the stability of the power system, and can the water level drop so much that there is no electricity production at all?
The average production of electricity from HE is about 30 percent per year, and it can vary according to hydrology, so in years characterized by good hydrology, that percentage can be higher and vice versa. For the sake of illustration, of the total electricity produced in Serbia in 2021, 33.33 percent of electricity was produced from HPP. Of course, when the water level drops due to drought, there is a reduction in production from HPP. These days, due to the drought, the production from HPP makes up about twenty percent of the total electricity production in Serbia. Also, it should be borne in mind that due to environmental protection, river flows must be kept above the biological minimum, so in situations of extreme droughts, this can also affect production from HPPs.
Does this mean that due to the lack of water, we have to go to the additional import of electricity?
Production and imports are planned through annual balances with average hydrology with 75 percent probability. If the hydrology is worse than planned, those missing quantities must be replaced, so if there is not enough capacity from other sources, then the import of electricity must be resorted to.
In this situation, when we normally import both electricity and coal due to shortages, do gas thermal power plants have to be additionally activated due to the drought, where the production of electricity is twice as expensive?
It all depends on the costs. If you have gas and if the production costs from gas thermal power plants are lower than the current price of electricity on the stock market, then gas thermal power plants will certainly be activated. The marginal costs of electricity production from gas-fired thermal power plants for one megawatt-hour of electricity can be estimated as twice the price of the amount of gas that has a calorific value of one megawatt-hour. Currently, if you look at the price of gas on the stock exchanges, which is around 200 euros per megawatt-hour, the price of a megawatt-hour produced in gas-fired thermal power plants is around 400 euros, and to that price in the European Union should be added the obligation to pay the tax for carbon emissions -dioxide, which now amounts to about 40 euros per megawatt-hour for the production of electricity from gas, leads to a price of electricity of 440 euros, which essentially dictates the current prices on the market.
What does EPS do in case of bad hydrology and where do we get the most electricity? From the hydroelectric power plant HE “Đerdap”?
As already mentioned, in cases of bad hydrology, the planned production from HPP must be replaced by production from other sources or by importing electricity. As for HPP production, the “Đerdap 1” hydroelectric power plant accounts for about 37 percent of the installed capacity of all HPPs, and accordingly, the largest HPP production is at HPP “Đerdap 1”, which last year produced 46 percent of the total electricity produced at the HPP, Politika writes.
