This is an extract from a recent report “Türkiye can bypass grid constraints with hybrid solar power plants” by EMBER.
Grid connection capacity challenges in Türkiye and worldwide
Over a 15-month period, 65% of the capacity applying for grid connection at the transmission level in Türkiye was unable to secure approval, while globally, the capacity awaiting grid connection has reached 1.65 TW. The adequacy, reliability, and security of Türkiye’s electricity grid are the responsibility of the Turkish Electricity Transmission Corporation (TEİAŞ). TEİAŞ announces the regional capacity available for connection to the transmission and distribution grids, based on planning studies and identified needs. If there is no available connection capacity in a region, new power plant applications are rejected. In a decision by the Energy Market Regulatory Authority (EMRA) at its meeting on 8 February 2024, a total of 7.5 GW of capacity was allocated for the grid connection of unlicensed power plants. According to the breakdown published by TEİAŞ, half of this capacity was reserved for transmission-level connections, and the other half for distribution-level connections. Of the 3.5 GW allocated for transmission-level connections, 96% was distributed within just two months, and as of September 2024, no new capacity was left to be distributed. Since September 2024, no new transmission-level capacity announcements have been made. As a result, connection applications at the transmission level have been rejected since September 2024. Between February 2024 and April 2025—a 15-month period—65% (7.5 GW) of the total 11.6 GW of unlicensed project applications were rejected due to regional capacity constraints. The 7.5 GW of unauthorised capacity is almost a third of the total solar capacity installed by May 2025 (22.5 GW).
At the distribution level, the capacity available for connections is highly limited. According to the published announcements by TEİAŞ, 87% of the 3.5 GW capacity available for the distribution grid was allocated in 2024, leaving 0.48 GW yet to be allocated. In February 2025, the available capacity was increased by 22% (+0.1 GW) compared to the previous month, reaching 0.58 GW. According to the latest announcement published in May 2025, 0.52 GW of capacity remains available for distribution-level connections.
The limited capacity of Türkiye’s electricity grid is negatively affecting the growth of renewable energy capacity. Across both transmission and distribution levels, the available capacity for unlicensed plants in Türkiye is only 0.52 GW. This slows down the realisation of new solar investments in Türkiye, a country with high solar potential. The investment costs required for new grid infrastructure are among the main barriers to increasing capacity allocations. According to TEİAŞ’s 2024–2028 Strategic Plan, 74% of the total 362 billion TL budget planned for the five-year period will be allocated to the renewal and development of the electricity grid. According to the analysis conducted by TEİAŞ and published in its Strategic Plan to assess external factors that may affect its operations and strategic decisions, economic factors have been identified as the second most important element likely to impact the organisation in the future, after technological factors. A closer look reveals that economic risks—such as exchange rate fluctuations and high inflation, which vary depending on domestic and international developments—pose significant challenges to achieving targets by affecting contracts with contractors.
The issue of insufficient capacity for grid connection is not only a challenge for Türkiye, but also a common problem faced by many countries. As of July 2024, the total capacity of wind, solar, and hydroelectric projects in the final evaluation stage awaiting connection approval reached 1.65 TW worldwide, marking a 10% increase compared to 2023. This is equivalent to 38% of the current global total installed capacity for these three energy sources. In Europe alone, 0.5 TW of wind capacity is awaiting connection approval across 10 European countries, including ones where wind power exceeds 10 GW in installed capacity such as Germany, Spain, and France. Declining renewable energy investment costs and incentives provided by countries in line with their decarbonisation targets have led to a significant increase in renewable power plant projects. However, the development of grid infrastructure is insufficient to meet this rapid increase. For example, in Europe, it can take up to 9 years for a wind farm project to obtain a connection permit. In the UK, the average waiting time for a project to obtain a connection permit is 5.5 years, but in some cases it can be as long as 15 years.
Implementation of new infrastructure investments to enable the connection of power plants is time-consuming due to high costs, procurement issues and lack of skilled labour. Construction time for high voltage projects can range from 5 to 13 years, depending on the region, technology and targeted capacity. At lower voltage levels, this period can be reduced to 4 to 8 years. Investments at the distribution level can usually be completed within 4 years. Technical assumptions used in grid planning can also negatively affect the process. System operators plan the grid by taking into account high-risk conditions and unrealistic situations, and act on the assumption that resources with variable generation profiles, especially wind and solar, will produce at maximum capacity for long periods of time. This cautious approach leads to an underestimation of the grid connection capacity, leading to an increase in the number and capacity of power plants waiting for connection.
Data deficiencies are failing to guide investors effectively. Throughout Europe, investors have very limited access to current and detailed data that would show where adequate capacity is available for grid connection. This lack of information makes it difficult for investors to select the right locations and develop projects that will avoid grid connection issues. Denmark’s system operator, Energinet, has developed excellent tools to improve visibility and help address this issue. Along with technical obstacles, procedural shortcomings are also slowing the process. In the evaluation process, the inclusion of projects with a low probability of realisation prolongs the evaluation period for projects with a high realisation potential. To avoid this problem, countries such as France, Greece and Romania have tightened the application criteria. In order to apply, projects are required to complete certain permitting and procedural steps determined by the institutions.
Another method is to prevent speculative projects from applying by increasing financial obligations. While Romania and the UK impose an application fee for projects, in countries such as Greece, Spain, Italy and Romania, system operators require bank guarantees from projects applying for connection. If authorised projects do not connect, they forfeit some or all of their collateral and lose their connection authorisation. The application systems in Türkiye and Europe differ. In Türkiye, for projects to be considered for evaluation, applications must meet the conditions and timeline set by the Energy Market Regulatory Authority (EMRA). In most of Europe, however, investors can apply at any time and be included in the evaluation process. Furthermore, in many European countries, the principle of “first come, first evaluated” applies. However, this system allows speculative projects with a low probability of success to be included, which extends the evaluation time for projects that could be connected to the grid and slows down the pace of energy transition. It is clear that grid connection challenges are not unique to Türkiye, and for all countries there is much to learn from how other countries have failed and succeeded in tackling bottlenecks. Enhancing data transparency to enable realistic projections, along with improved application processes that prioritise high probability projects, will help accelerate the energy transition.
Status of hybrid solar plants in Türkiye
Since 2019, Türkiye’s installed solar power capacity has increased by 16.1 GW, yet despite the installation advantages and compatibility with other sources, hybrid solar capacity has reached only 1.4 GW. Hybrid power plants were first included in Türkiye’s regulations in March 2020. However, in the first two years, installed capacity reached only 100 MW. This limited development paved the way for new regulations that opened the path for hybrid investments. In March 2022, a decision was made to allocate 1.3 GW of capacity for hybrid plants. Under this decision, the maximum hybrid capacity that plants could apply for was limited to 15% of the installed capacity of the main plant, excluding wind. By August 2022, only 42% of the announced capacity had been allocated, leaving 0.8 GW of capacity remaining. With the regulatory change implemented in September 2022, the 15% restriction was lifted, and by January 2023, 88% of the 1.3 GW capacity had been allocated to investors. In March 2023, the total capacity available for allocation was increased to 1 GW.
Türkiye’s total installed hybrid solar power capacity reached 1.4 GW in May 2025. Solar power plants are the most common type of hybrid power plants due to their ease of installation, low cost and efficiency in production. As of May 2025, nearly all of the 3.5 GW of production licenses granted were awarded to solar energy projects. However, only 41% (1.4 GW) of the licensed capacity has been put into operation.
Hybrid solar power plant installation licences have been granted to five different sources: wind, hydroelectric, biomass, geothermal and thermal. Wind power plants hold the largest share at 61% (2.2 GW), followed by thermal power plants with 15%, hydroelectric plants with 13%, and other renewable sources with 11%. Similar trends are observed in completed installations. Wind power plants, accounting for 66% of the commissioned capacity, stand out as the most common host for hybrid solar installations.
To further improve the utilisation efficiency of a power plant’s transmission line, complementary energy sources need to be planned jointly. In this regard, combining solar power plants with wind and hydroelectric plants is a key practice for improving efficiency. Seasonal variations in generation enable a high level of complementarity between solar power and run-of-river hydropower plants. Run-of-river hydroelectric plants do not have the ability to store water for future production. In Türkiye, the production capacity of these plants begins to increase in March when rainfall and snowmelt start, peaks in April-May, and begins to decrease in the summer months when solar plants achieve their highest production. When comparing the production profiles of these two sources, they are highly complementary. This complementarity is evidenced by a negative correlation between the electricity generation of run-of-river hydroelectric and solar power plants.
Hybrid solar power plants can help improve the efficiency of dammed hydroelectric plants. Dammed hydroelectric plants can store incoming water and shift their generation to different months based on price forecasts and rainfall conditions to maximise the efficiency of water used for production. In Türkiye, in the winter months of 2024, the correlation between dammed hydro and solar generation was close to zero (-0.06). However, a negative correlation of -0.33 in the spring and summer months indicates stronger complementarity. By utilising the energy generated from hybrid solar systems during the spring and summer, dam plants can store more water for use in winter when electricity prices are higher. This allows hydro plants to increase generation during winter, reduce reliance on fossil fuel-based electricity, and contribute to lowering energy imports.
As with hydroelectric power plants, solar energy can also complement wind power generation. In particular, during the summer, Türkiye’s wind generation typically begins to decline around 6am when the sun rises and reaches its lowest point around 9–10am. Wind generation then increases through the afternoon, peaking in the evening hours. Solar power plants, on the other hand, start generating around 6am and reach maximum output by midday. According to 2024 data, during the summer months when solar generation is at its peak, wind generation increases by 49% from its lowest point in the day to its maximum output. The hourly correlation between wind and solar generation during the 6am to 6pm period in summer months is approximately -0.10. Due to the variable and unpredictable nature of wind generation, combining it with solar generation can significantly improve the efficiency of grid connection lines.
Hybrid solar power plants clearly demonstrated their impact in Türkiye in 2024. In 25 wind and hydroelectric power plants where data was reliably accessible, the addition of hybrid solar power plants increased the amount of electricity delivered to the grid by an average of 14%. Thanks to this increase, the average connection capacity factor rose by 5 percentage points, reaching 32%. The impact is even more significant during solar’s summer peaks. During the summer months, when run-of-river production was at its lowest and solar production at its highest, hybrid solar plants contributed an additional 7 percentage points to the capacity factor, while in dammed power plants the contribution was 6 percentage points. In wind power plants, during July when solar production levels were highest, the contribution was 10 percentage points.
Hybrid plants can make solar the largest source of installed capacity in Türkiye
According to the analysis of hybrid solar potential conducted for privately owned wind and hydroelectric power plants, the total hybrid solar potential at these sites is 8 GW under current economic conditions. This potential is more than twice the total installed capacity of Türkiye’s geothermal and biomass power plants combined and is almost equal to the installed capacity of run-of-river hydroelectric plants (8.4 GW). As of May 2025, Türkiye’s installed solar capacity stands at 22.5 GW. If the 8 GW hybrid solar potential is realised, total installed solar capacity could surpass 30 GW—making solar by far the largest energy source by installed capacity in Türkiye.
Due to higher solar potential in regions in Türkiye with dammed hydroelectric power plants compared to areas with high wind power regions, 46% of Türkiye’s potential hybrid solar capacity is in dammed hydroelectric power plants. Geographical and meteorological factors at power plant locations significantly influence how much additional solar capacity they can accommodate through hybridisation. The total capacity of the power plants included in the analysis of hybrid potential accounts for 24% of Türkiye’s total installed capacity (29.1 GW). Dammed hydro accounts for nearly 32% of the capacity assessed, while wind accounts for 41%. More than half of Türkiye’s dammed hydroelectric power plants are located in the Mediterranean and Eastern Anatolia regions, where solar potential is high. As a result, 46% (3.6 GW) of the total 8 GW hybrid solar potential is associated with these plants. In contrast, 45% of wind power plants are located in the Marmara region, where wind potential is high but solar potential is relatively low. This situation leads to a lower hybrid solar potential at wind power plants—despite the total installed capacity of the analysed wind plants being 12 GW and dammed hydro plants being 9.2 GW. The hybrid solar potential at wind plants is 1.4 GW less than at dammed hydro plants.
According to the research carried out by experts at the Turkish State Meteorological Service, the effects of drought are expected to be felt even more strongly in Türkiye in the future. To offset the decline in generation expected from hydroelectric plants due to drought and to maintain the efficiency of the existing grid infrastructure, hybrid solar power plants are gaining even greater importance. According to the analysis, the estimated hybrid solar potential for hydroelectric power plants is 5.7 GW. If this potential capacity had been installed in 2021, the energy supplied to the grid by hybrid solar plants would have increased by 4% compared to 2020, and hydroelectric plants’ share in total production would have risen by approximately 2.5 percentage points. According to calculations by State Hydraulic Works (DSİ), Türkiye’s dam-type hydroelectric power plants have a floating solar potential of 53 GW. The annual generation potential of this capacity is nearly ten times higher than the generation estimated for the currently assessed 5.7 GW of hybrid solar systems. Realising this 53 GW potential alongside hybrid solar systems could help secure renewable electricity generation against the risk of drought that Türkiye may face in the future. If Türkiye had deployed 8 GW of hybrid solar capacity by 2024, the country’s electricity generation mix could have shifted. Analysis shows that these hybrid plants could have generated approximately 12 TWh of electricity, equivalent to 46% of Türkiye’s total solar electricity generation in 2024. With this additional generation, wind and solar together would have accounted for 21.6% of total production, placing them among the top sources, and just behind imported coal (21.8%).
Policy recommendations
Advancing hybrid power plants without requiring new capacity allocations: Hybrid power plants have the potential to bypass Türkiye’s grid connection constraints and increase the installed solar capacity. Since they use the same transmission lines as the primary source they are integrated with, they do not require additional grid investments. Because of this characteristic, the investment requirements for hybrid plants differ from those for new power plant projects. Therefore, hybrid plants should be considered through a separate process and evaluated without waiting for the announcement of new capacity allocations.
Removing the capacity cap: Under the current system, plants with an installed capacity of less than 50 MW can receive hybrid capacity up to their installed capacity. Plants with an installed capacity above 50 MW can receive an additional capacity equal to 50 MW plus half the difference between their installed capacity and 50 MW. Hybrid capacity is capped at 100 MW, regardless of a power plant’s installed capacity. These rules came into effect in April 2021, and as of October 2022, the 100 MW cap rule was ceased for wind power plants. A new regulation that removes the capacity cap rule and allows investors to decide how much additional hybrid capacity to install would make it easier to realise Türkiye’s hybrid potential. To prevent grid overload, excess generation could be curtailed or penalised as necessary.
Removing the site adjacency restriction: One of the biggest obstacles facing hybrid projects is the requirement for these projects to be physically integrated within the primary source’s power plant site. In practice, when existing licensed power plants try to identify new areas adjacent to their primary plant site for hybrid projects, these areas often fall into restricted zones, such as agricultural or forest lands. Removing the requirement for hybrid projects to be adjacent to the primary source’s plant site—while ensuring they connect to the same transformer station and do not require new grid infrastructure investments—could significantly accelerate the hybridisation process.
Setting targets and ensuring data transparency: The inclusion of hybrid power plants in Türkiye’s recently announced 2053 targets is a positive development. However, as with other energy sources, it is essential to set clear numerical targets for hybrid projects and share them with the public. This would ensure that hybrid power receives the necessary attention and that concrete steps are taken to achieve the targets. Currently, installed capacity data does not include figures for hybrid plants. Likewise, it is not yet possible to track development trends through historical data sets, as is the case for other energy sources. Therefore, it is crucial to make data on hybrid plants more visible and accessible.
Access the report here
