Power producers transform into distributors due to reversed energy flow patterns in Slovenia

In the heart of Europe, Slovenia is navigating a significant shift in its energy landscape. The mass integration of distributed energy sources, particularly solar power plants, has disrupted the traditional voltage profiles on the grid, according to Boštjan Turinek, director of operations and development at Elektro Celje.

One of the greatest challenges during this energy transition is managing voltage profiles on the grid. However, recent events have shown promising signs of a balanced energy system.

On May 1 and 2 this year, all Slovenian power distribution companies collectively supplied more electricity to the transmission network than they received. This remarkable occurrence, known as reverse energy flow, was first recorded at Elektro Celje, amounting to approximately 4 MW on July 2022. By this year, the reverse flow at Elektro Celje has reached 100 MW.

The weather during the first two days of May was clear, but not warm enough for people to use air conditioners, while solar power plants were generating electricity at nearly full capacity. If the weather is sunny during holidays or collective shutdowns of industrial plants, the output from distributed energy sources can be very high.

During these periods, industrial plants were not working due to the holiday, and many people were away from home, contributing to the decrease in electricity consumption. On May 1 and 2, electricity consumption from the transmission network fell sharply, reaching only 150 MW between 12 and 1 p.m., compared to winter peak hourly consumption of around 2,200 MW.

The total capacity of solar power plants in Slovenia is 1.4 GW, with half of it installed in 2023 and 2024. Distributed power plants, like those owned by solar power plant owners, have been granted the same rights as emergency vehicles, ensuring their output always takes priority, regardless of the state of the grid.

Elektro Maribor, Elektro Celje, and Elektro Gorenjska delivered significant amounts of electricity to the transmission network, while Elektro Ljubljana and Elektro Primorska drew energy from it. Pumped storage hydropower plant Avče was operating at full capacity and received 157 MW from the transmission network.

The net metering system for prosumers (producers and consumers of their own electricity) has had many positive effects, but it has also created numerous problems, Turinek concluded. Ordinary consumers may experience slightly shortened lifespans of their LED bulbs due to the disrupted voltage profiles, but solar power plant owners often experience automatic inverter shutdowns caused by overvoltage.

If the power system is to be properly managed, distributed power plants should be placed on an equal footing with all others, according to Turinek. The overall electricity generation capacity in Slovenia is 7.47 GW. However, no relevant information about which company supplied the most electricity to the transmission system between 11 a.m. and 3 p.m. on May 1 of this year was found in the search results.

In conclusion, Slovenia's energy landscape is undergoing a significant transformation, with the integration of renewable energy sources leading to reverse energy flows and a more balanced energy system. As the country continues to invest in solar power, managing the voltage profiles on the grid will remain a key challenge.

Power producers transform into distributors due to reversed energy flow patterns in Slovenia