Climate change affects all aspects of our lives, and energy transition has become an imperative of the modern era. However, the energy crisis last year caused by the war in Ukraine showed us that the transition is slower than expected. Overnight, we became aware of the fragility of our energy security, which forced us to seriously consider how to better prepare for possible future challenges. In this analysis, RESC offers possible solutions for achieving 100% renewable energy in domestic production by 2030 and thus achieving energy self-sufficiency

The analysis is based on a detailed modeling of the evolution of electricity production and consumption and numerous simulations of the operation of the Croatian power system in different time frames. It also proposes ways to accelerate the transformation of the power system to strengthen resilience to different crises.

Uniform growth of solar and wind power plants toward energy independence

Based on current consumption and its trend of growth, as well as the current need for imported electricity, the analysis shows a possible energy picture of Croatia in 2030 with 100% renewable energy. Annual electricity consumption of 21 to 23 TWh would be satisfied by generating electricity mostly from solar and wind power plants in Croatia.

On January 1st, 2030, according to this scenario, Croatia would have 2,500 MW of wind farms that produce 6 TWh of electricity per year. It would also have 2,500 MW of solar power plants that produce 3 TWh of electricity per year. Additionally, we would develop 400 MW in other renewable energy projects such as biomass, biogas, and geothermal power plants, which would produce 2 TWh of electricity per year.

So, in 2030, with an average hydroelectric production of 6,344 GWh, other renewable energy sources would produce about 17 TWh or primary energy of 42 TWh. This is equivalent to the production of electricity from 4.2 million tons of natural gas or 3.1 million tons of liquefied gas, 3.6 million tons of oil, and 5.9 million tons of coal, which is about 42% of the current primary energy consumption.

It is expected that the construction of the Senj2/Kosinj hydroelectric system with a capacity of 412 MW will be completed by 2029, increasing the annual production of the Senj hydroelectric system by approximately 220 GWh. In addition to the construction of new wind and solar power plants with variable production, new flexibility resources will also need to be built by 2030 to provide system balancing services on both the production and consumption sides. This includes new reversible hydroelectric plants with a capacity of +600/-600 MW, annual consumption of around 2.5 TWh, and non-renewable production of 1.875 TWh of electricity. New batteries will also be needed for storage services and system balancing services. We will also need stable and flexible electrolyzers to produce hydrogen, which would store surpluses in the system during high production from hydroelectric, wind, and solar power plants.

Of course, an important condition for such an energy outlook in 2030 is the development of the transmission and distribution network. In particular, the development of a new double 400 kV transmission line, with a transmission capacity of around 2500 MW, between Dalmatia and northwestern Croatia, should be highlighted. With all of the above, this would be the best scenario for the mid-term development of the power sector strategy based on 100% renewable energy sources, but it requires significant investment while giving low operational costs (electricity prices) during operation.

Investments needed to achieve energy self-sufficiency

Investments needed to achieve these energy goals amount to around one billion euros annually. Of that, 500 million euros would be required for the construction of solar and wind power plants, 300 million for the rehabilitation, modernization, reconstruction, replacement, and digitization of transmission and distribution network elements, and 200 million for energy storage technologies (new RHE technologies, batteries, and hydrogen). This is a financially accessible goal and represents 1.62% of GDP, which amounted to 61.892 billion euros in Croatia in 2022. This would fulfill all EU requirements for the development and decarbonization of the energy sector, which are emphasized in the REPowerEU plan. Croatia can achieve this without much difficulty.

Plenty of solar power plants in 2030

According to this analysis, Croatia can and should have an abundance of megawatts of solar power plants. The electric energy balance on an annual and monthly basis in 2030, assuming an annual consumer consumption of 22,618 GWh (higher growth scenario) and RHE consumption in pump mode of 2,413 GWh, as well as average hydrology, wind and cloudiness while retaining existing production capacity, is shown in the following images:

The balanced energy balance is visible with low imports, as well as reduced production of thermal power plants and other fossil fuel power plants, reduced CO2 emissions, and high production of renewable energy sources.

Without imports with production from renewable sources of energy

According to the categories of available energy sources in 2030, renewable energy sources account for 68.7% of electricity production, non-renewable sources for 20.2%, and the Krško nuclear power plant (50%) for 11%. The exchange balance is zero, meaning that the electricity balance would be completely balanced. According to this scenario, we will not need imports in 2030.

It should be emphasized that among non-renewable sources, reversible hydropower plants participate in electricity production with 7.8%, and fossil fuel thermal power plants with 12.4%. The overall available energy would be “burdened” with CO2 emissions of 81g/kWh, which would place Croatia in 2030 among EU countries with the highest achieved decarbonization.

The hydroelectric power plants would still produce the most renewable electricity, but wind farms would overtake them in further development by 2035. The image below shows a uniform production of renewable energy during 2030, as well as a high production from solar power plants, especially during summer when the production of hydroelectric power plants is reduced. This is a goal that we would like to see achieved even before 2030.

Based on the monthly balances, it is visible that wind farms and hydroelectric power plants produce more energy in the autumn-winter season, while solar power plants produce the most energy in the spring-summer season, accounting for about 70% of the annual production between April and September. This results in a more even monthly production, and therefore a more secure supply for consumers and the operation of the power system.

Forming a Virtual Power Plant

The analysis of current trends predicts that greenhouse gas emissions will continue to rise until 2030, with a simultaneous increase in temperatures worldwide. Therefore, accelerating the energy transition is of crucial importance, which implies a change in our patterns of energy consumption and production. It is clear that renewable energy sources depend on weather conditions and cannot always produce the same amount of electrical energy. Therefore, it is important to create a system of multiple producers and consumers of electrical energy that manage consumption and return stability to the power system as needed. Virtual power plants are precisely such a system where all parties involved benefit. According to the definition, a Virtual Power Plant (VPP) is a software-based system and smart technology that remotely manages aggregated resources with the aim of providing services on the wholesale or retail market through an aggregation and optimization platform.

July 2030: Simulation of the operation of a 2500 MW wind power plant with an average load factor and a 2500 MW solar power plant based on a substitute curve with average cloud cover on an hourly basis.

By building 2500 MW of wind and solar power plants and a new +600/-600 MW RHE technology by 2030, a virtual power plant can be formed with or without the Velebit RHE, which would provide a very reliable, predictable, stable and manageable energy supply to the system. The plan and operation of this virtual power plant can be fully digitally controlled. The image below shows the operation of the system with the virtual power plant and a simulation for July 2030.

July 2030: A virtual power plant managing 2500 MW of wind power, 2500 MW of solar power, and a new 600/-600 MW reversible hydroelectric power plant, as well as the Velebit reversible hydroelectric power plant at 276/-240 MW, has an average capacity of 1.072 MWh/h. This is 3.1 times greater than the Croatian portion of the Krško Nuclear Power Plant (50%).

The function of the virtual power plant is to convert variable wind and solar power production into reliable and stable energy, balance the power system, and ensure the operation of thermal power plants at optimal operating points.

The above picture shows how in July 2030, virtual power plants are transforming the production of wind and solar power into reliable and stable production.

SUNNY DAYS 2023

There is no longer any doubt about the long-term abandonment of fossil fuels based on major changes in energy consumption and production patterns, in order to limit the effects of climate change and increase Croatian energy sovereignty.

Analysis of Croatian electricity consumption, production, and exchange with neighboring countries is carried out on a precise time scale and updated every month. Thanks to these analyses, it is possible to predict future scenarios for the development of our power system, which can become a key tool for managing and planning the development of the power system.

It is already apparent that achieving energy self-sufficiency goals is possible with a new 600/-600 MW RHE of new technology, 2500 MW of wind power, and 2500 MW of solar power. Croatia can achieve this without major issues.

Solutions for the accelerated development of much-needed new solar power plants in Croatia will be presented at the SUNNY DAYS conference in Bol on the island of Brač on May 25-26. Stronger development of solar power plants, the use of agrivoltaics, the involvement of energy communities in solar projects, and the definition of “Go-to” areas for the accelerated development of renewable energy sources are just some of the important topics for faster development of solar projects and achieving energy self-sufficiency goals that will be discussed at the conference.

The SUNNY DAYS conference is essential for anyone who aims to make better use of solar energy and develop new megawatts of solar power plants! There is an extremely high interest in participation, so reserve your spot in time! You can sign up HERE.