The largest part of electricity generated by Latvenergo AS comes from the three leading hydropower plants in Latvia. These plants generate at an average 70% of the total generated electricity. The total capacity of Kegums HPP is 264.1 MW, Plavinas HPP – 868.5 MW, and Riga HPP – 402 MW. In addition, the company owns Aiviekste HPP, which generates electricity with the capacity of 0.8 MW. In total in 2009, the hydropower plants of Latvenergo AS, including Aiviekste HPP, have generated 3440 GWh – 71% of the total electricity generated by Latvenergo AS.
Plavinas HPP with its ten hydroelectric sets (HS) is the largest hydropower plant in the Baltic States and the second largest in the European Union in terms of installed capacity.
The first hydroelectric set of Plavinas HPP was launched in December 1965, whereas the State Commission approved the power plant’s putting into full operation in 1968. The planned overhaul of six HSs has been accomplished during the period from 1991 to 2001.
As a result, the plant’s installed capacity reached 868.5 MW. The previous major reconstruction of the hydroelectric sets of Plavinas HPP was carried out from 1999 to 2001, when HSs No. 2 and 8 were modernised. The reconstruction of HSs No. 4, 5 and 7 was commenced at Plavinas HPP in 2007. This is the second largest reconstruction project at this hydropower plant, and its completion is scheduled by spring 2010. Within this project, the reconstruction of HS No. 4 has already been completed. The completed works include the reconstruction of generator stator and replacement of exciting system and control protection equipment.
In May 2008, the reconstruction of HS No. 5 was commenced at the power plant. The planned works include the hydroturbine wheel and generator stator winding replacement. As a result, the equipment efficiency will increase for up to 93% and the capacity – for 7.5 MW, reaching 90 MW instead of the current 82.5 MW. It is planned to complete the reconstruction of HS No. 5 by March 2009 and then perform the same reconstruction works for HS No. 7 to be completed by spring 2010.
The total project investment costs constitute 29.6 million lats: 8.4 million in 2007, 10.6 million in 2008, 9.7 million in 2009 and 0.6 million in 2010.
Once the project is implemented, the electricity generation amount will increase at an average of 30 GWh per year (for comparison: 149 small HPP in Latvia generate roughly 60 GWh) due to increased capacity and efficiency of the hydroelectric sets. The term of operation of the overhauled sets will extend for at least 30 years, while the maintenance and repair costs will be reduced for about 40%.
At Plavinu HPP, increased attention is paid to the safety of hydrotechnical constructions. The modernisation of hydrotechnical construction safety monitoring and control equipment has been performed, implementing a computerised system for the observation data collection and processing. In 2009, Plavinas HPP generated 1980 GWh of electricity.
Kegums HPP is the oldest hydropower plant on the river Daugava and the third largest in Latvia. As a matter of fact, it is a hydropower plant complex consisting of two plants built at different periods of time. One of them is situated on the right bank of Daugava (the first plant), whereas the second (the newer one) – on the left bank.
Kegums HPP-1 is the oldest hydropower plant of Daugava (built in 1936 – 1940), and it has four hydroelectric sets. It was built back in the years of the first Latvian independence period, which means that, from the three largest HPPs, it is the only one that can be deemed as built for meeting the need of individual electricity supply for Latvia. Kegums HPP-1 underwent reconstruction from 1998 to 2001: all of its four hydroelectric sets were replaced and their control systems – automated. The construction of Kegums HPP-2, in turn, was started in 1976, and the plant was launched in 1979. HPP-2 has three HSs with the aggregated installed capacity of 192 MW.
The total amount of electricity that Kegums HPP generated in 2009 was 667 GWh.
Riga HPP was put into operation in 1974, and it is the newest of Daugava’s hydropower plants. It has six hydroelectric sets with the total capacity of 402 MW. To regulate voltage in electrical networks, the plant can also be operated in the synchronous compensator regime, which allows compensating the power deficiencies.
At Riga HPP, much attention is paid to the safety of hydrotechnical constructions: the earth dam safety has been improved; a special computer programme has been implemented for the monitoring and analysis of the dam’s condition; the concrete constructions and surfaces of Riga HPP are constantly renewed. In 2009, Riga HPP generated 792 GWh of electricity.
Aiviekste HPP
The first hydropower plant in Latvia started to generate electricity in 1925. From 1925 to 1938, Aiviekste HPP was the largest in Latvia: the total power of its hydroturbines was 1070 Hp, allowing – in congenial meteorological conditions – to generate about 5 GWh of electricity per year. Although Aiviekste HPP was put out of service in 1969, it was included in the list of restorable power plants already in 1988. The restoration of the hydrotechnical constructions of the hydropower plant was commenced in 1993, and the plant was put into operation in a year, launching the Francis turbine procured from Sweden.
The total capacity of Aiviekste HPP is 0.8 MW. In 2007, the plant generated 3 GWh of electricity in total – approximately 0.1% of the overall amount of electricity generated by Latvenergo AS.
