THE POWER OF THE SUN: 02-07-2023 – A new milestone in the history of Hungarian solar power plants

27. 07. 2023.

Could you have ever imagined such a remarkable feat? During sunny periods, the collective output of domestic solar power plants can exceed that of the Paks nuclear power plant by more than double!

In recent times, Hungary’s installed solar capacity has surpassed 5000 MW, marking a significant milestone in the country’s renewable energy production. The rapid expansion of solar power plants brings numerous advantages for sustainable development and energy diversification. However, such a substantial growth in the number and capacity of weather-dependent power plants presents considerable challenges for the electricity grid and MAVIR (Hungarian Transmission System Operator Ltd.), as they must ensure grid stability.

According to data from the domestic transmission system operator, as of 1st Jukl, the total installed capacity of industrial (over 50 kW) and household-sized (below 50 kW) photovoltaic systems reached 5038 MW. By comparison, the Paks nuclear power plant has an installed capacity of approximately 2000 MW, meaning that during sunny periods, the total output of domestic solar power plants can be more than twice that of the Paks nuclear power plant.

Figure 1: Changes in the installed capacity of household-sized , permitted and non-permitted photovoltaic small power plants. / Source: MAVIR

However, such a high penetration of renewable power plants on the grid is already causing significant fluctuations in the electricity market. On July 2nd, a Sunday, a very unique situation arose in the Hungarian electricity exchange.

As it was a Sunday, industrial consumption was low, while domestic solar power plants were producing at their peak, as shown in Figure 2. Consequently, domestic power generation far exceeded consumption during the day, leading to a substantial amount of energy being exported. However, at the same time, the international energy market was experiencing a similar situation: renewable power plants (wind and solar) were producing, but there was insufficient demand to consume this surplus electricity.

Figure 2: Distribution of domestic power generation and the export-import balance. / Source: MAVIR

Since large-scale electricity storage is not yet feasible, shutting down the generating power plants is costly, and exporting energy provides only a partial solution, as the interconnected European grid also has excess power. Therefore, the only option left is to sell the surplus electricity at any cost. As a result, on Sunday afternoon, the market was willing to pay 500 euros per MWh for someone willing to consume the excess energy (Figure 3).

Figure 3: HUPX DAM Prices (EUR/MWh) – 2 July, 2023 / Source: HUPX

Of course, this does not mean that everyone who consumed electricity during that time received payment for using it, as the situation is more complex due to energy trading contracts. Nevertheless, the event highlighted significant challenges related to weather-dependent power plants.

The rapid expansion of solar and other renewable power plants poses challenges to grid stability. The most obvious problem is the variability of solar power plant productivity.

Solar power generation depends on the time of day and weather conditions, especially sunlight intensity and cloud cover. The variability of weather conditions can cause fluctuations in production, posing challenges for the system operator in maintaining grid stability and balance and, as seen, leading to unforeseen effects on energy markets.

Despite these challenges, solar power plants have significant advantages over conventional power plants. They contribute to reducing carbon dioxide emissions and mitigating climate change. Therefore, the spread of renewable power plants is an important and supportable process. Sunlight and wind are free and unlimited environmentally friendly energy sources, making their utilization crucial in establishing a sustainable electricity system. The combined use of wind and solar energy can help moderate the fluctuations caused by weather in electricity supply.

Therefore, it is particularly disadvantageous that the current regulations in Hungary hinder the installation of new wind power capacities. It is essential that, alongside the construction of solar power plants, wind power investments can be resumed, but to achieve this, the current regulatory framework must be restructured.

To prevent the problems presented in the article, it is essential to improve the accuracy of solar and wind power production forecasting, further develop storage technologies, support projects for maintaining a diversified electricity grid, enhance system security and digitalization, and modernize and transform energy market mechanisms!