A hydroelectric power plant (HEPP) is a power plant that converts the energy of flowing water to electricity. The water flowing in a large river contains a huge amount of energy. The energy of the flowing water or the falling water is used to generate electricity.

The main process in hydropower is to convey the water behind the dam, from a certain height, to the turbines located at a lower elevation. The water hits the turbine blades with high velocity and great force, rotating the turbine runner. This in turn rotates the generator and electricity is produced. After its energy is used, the water is released through the tailrace back to the river bed, without any processing. Therefore, no water is lost; no water pollution occurs either.

Kalehan Energy companies were awarded licenses by the Energy Market Regulatory Authority for 3 projects in the region. The projects are located in the provinces of Elazığ, Bingöl and Muş and will all be built on the Murat River. These projects, from the most upstream to the downstream, are;

• Yukarı (Upper) Kaleköy Dam and Hydroelectric Power Plant (626,85 MWe): located in Bingöl Province, Solhan District (dam site, reservoir), and Muş Province, Central District (reservoir);
• Aşağı (Lower) Kaleköy Dam and Hydroelectric Power Plant (500,00 MWe): located in Bingöl Province, Central District (dam site, reservoir), Genç and Solhan districts (reservoir); and
• Beyhan 1 Dam and Hydroelectric Power Plant (582,10 MWe): located in Elazığ Province, Palu District (dam site, reservoir), and Bingöl Province, Genç District (reservoir).

Hydroelectric power plants can be classified in two main groups according to their storage capabilities; HEPPs with storage (dam and reservoir) and run-of river HEPPs without storage (diversion weir). Run-of-river schemes produce energy using only the force exerted by flowing water. In this type of HEPP, the height of the structure that diverts the river water to the turbines is not as tall as that in a “dam and reservoir” scheme and is usually referred to as a “diversion weir” instead of a “dam”. A small lake forms behind the diversion weir, which provides a small amount of storage or no storage at all. Therefore, the amount of energy generated by run-of-river HEPPs varies annually and seasonally.

In a storage scheme HEPP, water is stored behind a tall dam and energy is produced using the force exerted by the water as it falls from a great height. The water stored during rainy seasons is used for energy production during dry seasons. In multi-purpose schemes, the stored water is also used for irrigation or drinking water supply. Dam height determines the amount of force exerted by the falling water and therefore the amount of energy produced; whereas reservoir volume determines how much annual energy production will be affected by seasonal fluctuations in river flow. 

Yukarı (Upper) Kaleköy, Aşağı (Lower) Kaleköy and Beyhan‑1 projects are storage schemes.

Hydroelectric power plants are not planned or designed considering only one project at a time. Rather, existing and planned developments in the upstream and downstream of any given project are considered in a cumulative analysis. The objective is to utilize the available flow and head in the whole river basin in the most efficient way at an acceptable cost.

The planning studies for the section between Alparslan-II Dam and Keban Dam, where Kalehan Energy’s projects are located, were initiated in the 1980’s by the General Directorate of Electrical Power Resources Survey and Development Administration (EİE). The findings from these studies were published as the “Revised Report on the Reconnaissance Survey of the Energy Potential between 850-1240m Elevations in the Murat Branch of the Euphrates” (“EİE Report”) in 1989.

These initial surveys were followed by Master Planning studies carried out with the objective of maximizing energy generation while minimizing affected agricultural lands. As a result, 3 projects were developed with 1,708.95 MWe total installed capacity and 4 billion 762 million kilowatt‑hours total annual production. Detailed analyses of dam location and height alternatives were carried out not only on a project basis but also cumulatively as a whole, utilizing the hydroelectric potential as fully as possible. Thus, the formulation that provides the highest contribution to national economy was selected. During this selection process, all related authorities, notably the General Directorate of State Hydraulic Works (DSİ) and the Energy Market Regulatory Agency (EPDK), were informed and their approvals were obtained.

As dam height increases, costs of construction and land acquisition as well as the amount of energy produced also increase: below a certain height, the benefit-cost ratio decreases and the project becomes unfeasible. Both tall dams and smaller dams are planned at different locations along a river in such a way that the total reservoir area is minimum. Thus, lands and settlements to be inundated are minimized while energy production is maximized by utilizing the available head as fully as possible. In other words, the optimal dam height is determined considering technical, financial, environmental and social factors together and also the existing and planned projects in the upstream and the downstream.  

The total annual energy produced by Kalehan Energy’s projects constitutes 1.6% of Turkey’s annual electricity production and 7.3% of hydroelectric power generation in Turkey.

This corresponds to the amount of electrical energy consumed by 1.4 million people in a year. In other words, the combined annual energy demand of the provinces of Elazığ, Bingöl and Muş can be met. 

Electrical energy is supplied from 3 main sources:

• Hydroelectric, such as HEPPs with storage and run-of-river HEPPs;
• Other renewables, such as wind and solar;
• Thermal, such as coal and natural gas.

Flue gases from thermal power plants utilizing resources such as coal and natural gas may lead to long-lasting damage to agricultural products, wildlife, water resources and forests, and also cause climate change. Besides, radon present in fly ash from thermal power plants may cause an increase in incidence of cancer. Utilizing an expensive energy source for which we are dependent on foreign production, such as natural gas, to generate electricity will not only increase energy costs but also our foreign dependency.

Energy production using renewable resources such as wind and solar energy depends on and therefore varies by natural conditions. Solar radiation is lower and weather can be cloudier in winter as compared to summer; energy demand, however, is high in winter. Furthermore, solar energy cannot be generated during the night. Wind turbines cannot be operated when the wind speed is too low or too high and their efficiency is around 30%. Therefore, solar and wind plants cannot meet on their own the overall annual energy demand in a region.

On the other hand, the average elevation is 1200m in Turkey and river gradients are also high. This topographic structure and hydrological conditions in Turkey provide advantages in hydroelectric energy production. Energy production cost is low in hydroelectric power plants and the energy source is both domestic and renewable. Hydroelectric power is more environmentally-friendly than other alternatives and capable of adjusting to changing energy demands.

Energy demand fluctuates throughout the day. In addition to the base load electricity that is required continuously, for 24 hours, during the day, more power is needed for lighting in the evening than in day-time. This is called peak load or peak demand. Peak load is also observed at noon hours in summer, owing to the increase in the use of air conditioners. Solar power plants cannot generate electricity at the time of evening peak loads because the sun sets. When wind of appropriate speed is not available at the required hours, wind power plants cannot supply peak energy demand either. The efficiency of thermal power plants decrease considerably when their units are started-up and shut down in the same day, and therefore they have a significant disadvantage when used as peaking plants.

Different from all other types of power plants, HEPPs with storage (reservoir) can supply a continuous load, and at the same time, provide for fluctuating energy demands during the day, without experiencing significant reduction in their efficiency. By operating a given number of units continuously and other units only during specific hours, HEPPs with storage can supply both base load and peak load energy demands.

Furthermore, like in Kalehan Energy’s projects, dam and HEPPs with storage (reservoir) provide flood control and can be used to supply irrigation and drinking water in addition to generating energy.

In developed and developing countries such as the USA, Canada, China, Japan, Russia and Norway, hydropower contributes significantly to their domestic energy generation. The contribution of hydropower in Turkey is 24% while it is 96% in Norway. China, one of the largest actors shaping global economy, contributes 28% to the world’s hydroelectricity production; Turkey’s share is just 2%.

Construction of new HEPPs continues at developed and developing countries alike. The total installed hydropower capacity worldwide is projected to reach almost double of current levels by 2050, for the goal of reducing annual CO₂ emissions that cause climate change to half of 2009 levels.

Moreover, in countries like Germany and the UK, reserve energy generation capacity is available for maintaining sustainability. In such countries, reserve capacity can be used in case of a power shortage. However, there is energy deficit in Turkey and therefore it is not possible to set aside any reserve energy capacity.

The national grid provides electricity to the region. The energy produced by Kalehan Energy’s HEPPs will be delivered to the national grid. Thus, the customers in the region will be able to use the energy produced by Kalehan Energy, though indirectly.

The economic life of hydroelectric power plants can be 50 years or longer. Their economic life can be extended up to 100 years by renewal of mechanical equipment and rehabilitation.

The Energy Market Regulatory Agency (EPDK) grants generation licences for 49 years. Kalehan Energy will operate its HEPPs during this period.