Reader's Forum


According to “Renewables 2016 Global Status Report” of REN21, the world´s total installed hydro capacity by December 31, 2015, amounted to 1,064,000 MW (please note that the 2016 edition of REN21 doesn't include pumped-storage capacity). Converted into electrical hydro generator output, this is equivalent to about 1,200,000 MVA. It would be interesting to know, how many hydro units are presently installed worldwide. It is also of interest, when these units were built, by whom and what the main technical data are.

There are some data bases published already, but, without exception, they give very limited information. Apart from the utility, plant name and other general information, the only technical data available is the unit MW output. It is therefore desirable, to compile a comprehensive hydro generator record containing the following data:

In order to limit the amount of work, only hydro generators with a unit output of 5 MVA and above will be considered. It is estimated, that the total installed hydro capacity of units below 5 MVA output is less than 3 percent of the total.

The most accurate way to put together a hydro generator data base is to rely on the information given by the user/operator or by the original equipment manufacturers (OEMs). All major OEMs have published so-called reference lists, which contain most, if not all, the above listed technical data. These reference lists serve not only as public relations instruments of OEMs, but are also an essential part of documentation submitted to utilities during the bidding process for new hydro projects.

Before approaching the respective OEMs for assistance in the described task, one has to determine which equipment manufacturers qualify for having delivered hydro generators of at least 5 MVA unit output. It is to be remembered that the first commercially utilized hydro generators were built and commissioned about 1880. The earliest hydro generators were using direct current (d.c.) technology. Because of its inherent transmission limitations, d.c. machinery was replaced by alternating current generators and a.c. transmission systems took on a state-of-the-art lead role. In 1891, Oerlikon built and installed a 300 h.p. three-phase hydro generator for the LAUFFEN power plant in Germany. The generator voltage of 55 Volts was transformed to 15,000 Volts (later 25,000 Volts) and was transmitted over a 175 km long overhead transmission line to Frankfurt. The system was officially inaugurated August 24, 1891. This date can be regarded as the starting point of a.c. three-phase power generation and transmission.

A 5 MVA hydro generator output may have been reached and exceeded about 1895.

According to an investigation currently in progress, there are about 120 OEMs that could qualify for the worldwide hydro generator data bank. Some of these companies have disappeared or have been absorbed by competitors. Also, as a result some new company names appeared. A preliminary list of hydro generator manufacturers can be viewed by clicking HERE.

The author would appreciate corrections or additions under to the above mentioned OEM list.

STATUS: November 30, 2016


The SANXIA hydro power plant is located in Central China on the Yangtze River, about 1,050 km upstream of the city of Shanghai. After preliminary completion in 2008, SANXIA was the world´s largest power plant, with a complement of 26 hydro generators rated at 700 MW each. The total project cost originally was estimated at 25 Billion US Dollars. With 6 additional generators installed in an underground powerhouse, the total project cost will increase considerably. After plant completion in May 2012, the annual electricity generation occasionally is in excess of 90 Billion kilowatt-hours, depending on precipitation conditions (see 7. PLANT FACTORS).

In 1997, an order for six Francis turbines and hydro generators was placed with the VGS consortium, then consisting of VOITH, GE HYDRO (Canada) and SIEMENS. After the amalgamation of the hydro activities of VOITH and SIEMENS in April 2000, VOITH SIEMENS HYDRO and GE HYDRO (Canada) became successor partners of the VGS consortium.

In April 2003, VOITH SIEMENS HYDRO entrusted HYDROPOWER CONSULT with the commissioning of the first two pure water-cooling systems and their associated direct-water-cooled stator windings. The Chinese designation of the two generators in question is Unit 02 and Unit 03. Commissioning was performed in May and June 2003. The third pure water-cooling system and stator winding (Unit 01) was commissioned by HYDROPOWER CONSULT in October 2003, whereas the fourth and fifth pure water-cooling system and stator winding (Unit 07 and Unit 08) were commissioned April 2004 and July 2004, respectively. HYDROPOWER CONSULT commissioned the sixth and final VGS pure water-cooling system and stator winding (Unit 09) in August 2005.

Major commissioning activities were as follows:

Originally there were two cooling options for the SANXIA hydro generator stator windings: Conventional air cooling or direct-water-cooling. The Chinese authorities selected a water-cooled design, which has the advantage of an increased stator winding insulation life and a substantial overload potential. The majority of hydro generators in China are air-cooled. According to the statement made by a Chinese specialist, other water-cooled hydro generators installed in China “have not been very successful” (1.). One can only speculate about the source of problems. The most likely cause is clogging of hollow copper conductors by copper oxide sediments. To avoid such problems, Siemens introduced a very effective solution in 1978, by increasing the pH value of the demineralized cooling water (2.). This method has also been applied to the SANXIA generators built by the VGS consortium. The expertise thus gained will now enable the Chinese operators to solve their water cooling problems, regardless whether hydro generators or thermal turbine-generators are involved.

The working language at the SANXIA site between Chinese personnel and foreign experts was English. As the number of qualified interpreters was very limited, working conditions for the foreign experts were occasionally hampered. The foreign experts were often trying to locate a competent interpreter and at the same time find workers to whom tasks could be delegated. It is remarkable in this context that there was not a single person at site with English as his native language as the entire GE HYDRO (Canada) workforce came from the province of Quebec and was of French descent, while the VOITH SIEMENS HYDRO staff were Germans and Brazilians.

The principal generator data are as follows:

Impounding of the upper reservoir commenced on June 01, 2003 and the first operational upstream water level of 135 m was reached on June 10. For improving navigation conditions and in order to increase electricity generation during the Yangtze River´s dry season (from about October to May), the water level was later increased by another 4 m. The new level was achieved on November 05, 2003. The second round of water impounding commenced on September 20, 2006 and was completed on October 28, 2006, when an upstream water level of 155.74 m was reached. The final head increase was carried out between September 28 and November 11, 2008. The maximum water level of 172.79 m achieved was slightly below of the design head of 175 m above sea level.

The first VGS unit, installed in #2 pit of the powerhouse, and therefore designated Unit 02, was the first SANXIA unit to be run up and reached rated speed on June 12, 2003. After successfully passing all scheduled commissioning tests, the generator was first synchronized with the Chinese grid on June 24, more than 6 weeks ahead of schedule. A maximum turbine output of 550 MW (at 135 m) was obtained June 26, 2003. Overspeed and load rejection tests were completed without problems.

Generator commissioning continued with a contractually-stipulated 72-hour trial run. Commercial operation of the VGS generator commenced on August 10, 2003, after successfully passing an additional 30-day operational trial run. The water level of the upper reservoir then present was 139 m above sea level. Generator output was therefore limited to about 600 MW.

Considering the magnitude of the project and the number of parties involved, one has to say that the actual commissioning was achieved in a remarkably short time. Counting the time span between first run-up and start of the 72-hour full-load run, commissioning of the first unit (Unit 02) was completed in only 19 days. This can largely be attributed to the high quality of the turbine and generator design and construction, as well as the high professionalism of the manufacturers’ personnel supervising the erection and commissioning activities.

The second VGS unit (Unit 03) also finished the 72-hour full-load run and the 30-day operational test run to the highest satisfaction of the China Yangtze Three Gorges Project Development Corporation.

The third VGS unit (Unit 01) was commissioned in November 2003. A new record was set, when commercial full-load operation commenced a mere seven days after first roll. More astonishing even is the fact that altogether six of the world´s largest generating units were placed into commercial operation within a six-month time period.

By September 2005, all of the 14 generating units in the left-bank powerhouse had been put in operation.

The first of the 12 generating units in the right-bank powerhouse was commissioned in June 2007. On October 30, 2008 the final unit went into operation, thus completing the original project.

In 2002 plans were issued to add six more generators to the project. These units are installed in an underground powerhouse. The final unit completed its acceptance tests at the end of May 2012.

Important lessons can be learned by the hydro industry and it would be worthwhile to analyze the background of this achievement and how the SANXIA project is being managed.

VOITH SIEMENS HYDRO has published additional information on the SANXIA project in a special issue of their customer's magazine August 2003 (3.).


1.) Huang Yuanfang:
Technical challenges for the design of the Three Gorges generating equipment.
Hydropower & Dams Issue Two, 1996, pages 32 - 36.

2.) K. Schleithoff, H.-W. Emshoff:
Optimization of the Conditioning of Generator Cooling Water.
VGB Kraftwerkstechnik 70, 9, 1990, pages 677 - 681.

3.) Voith Siemens Hydro:
HyPower Special Issue Three Gorges, China.
August 2003.

The construction of the Three Gorges Dam and Generating Station has been a controversial project both in China and abroad. One must conclude, that the Chinese Government felt that it would be to China´s advantage to proceed with this dam and generation development, as energy was badly needed. Of course, the project imposed hardships on the population in or near the development sites, as well as downstream. Additionally, due to unpredictable factors, the development poses certain future threats. The Chinese Government obviously is convinced that the benefits outweigh the risks. Alas, the official Government views could not be found on the internet.

The official SANXIA website (in Mandarin) is An English version can be activated on the SANXIA homepage at top right.

Interesting and detailed project information can be found on the internet under

The author would appreciate comments under

STATUS: November 30, 2016


The hydro generator business is dealing with a product of enormous dimensions and challenges.

Worldwide, there are at present quite a few 700 to 1,000 MW hydro generators in operation or construction. These units are designated for the following hydroelectric power plants:

GRAND COULEE (USA) 3 units of 805 MW each
GURI (Venezuela) 10 units of 730 MW each
ITAIPU (Brazil/Paraguay) 20 units of 700 MW each
SANXIA (China) 32 units of 700 MW each
SAYANO SHUSHENSKAYA (Russia) 10 units of 720 MW each
XIANGJIABA (China) 8 units of 800 MW each
XIAOWAN (China) 6 units of 700 MW each
XILUODU (China) 18 units of 770 MW each
WUDONGDE (China) 12 units of 900 MW each
BAIHETAN (China) 18 units of 1,000 MW each

To illustrate the dimensions, weights, outputs, centrifugal forces and other characteristics connected with large hydro generators, some examples are given below.


The following three examples well illustrate how much power or energy is delivered from an 800 MW hydro generator:


Radial acceleration forces are acting on all rotor parts, resulting in impressive centrifugal forces, as the following example illustrates:

For comparison: The Airbus A380 has an operational net weight of 280 metric tons and a maximum loaded take-off weight of 560 metric tons. The SATURN V moon rocket had a take-off weight of about 3,000 metric tons.


The WEHR unit has a stator bore diameter of 3.85 metres. Based on this dimension, the field pole surface speed at 600 rpm rated speed is about 121 metres per second, which is equivalent to 435 kilometres per hour (270 miles per hour). At runaway speed the pole surfaces would travel at a speed of 216 metres per second, equivalent to 777 kilometres per hour (483 miles per hour).


The generator rotor weight of a 50 Hz ITAIPU unit is about 2,000 metric tons.


The rotational energy is the kinetic energy due to the rotation of an object. This energy can be calculated by use of the moment of inertia and the angular velocity of this object. The kinetic energy of the 2,000 ton ITAIPU rotor at rated speed amounts to about 1,000 kilowatt-hours. At first glance this may not be an impressive figure to most of us. We have to bear in mind, however, that one kilowatt-hour is the energy an individual weighting 80 kilograms has to provide when climbing a mountain of 4,600 metres. Back to ITAIPU: An energy of 1,000 kilowatt-hours can lift the 2,000 ton ITAIPU rotor about 180 metres.


At 10 Eurocents per kilowatt-hour and with a plant factor of 100 percent, the income for an 800 Megawatt unit running at full output is Euro 1.920 million per day.

STATUS: November 30, 2016


The higher the output and the higher the rated speed of a hydro generator, the more demanding is the design. For visualization, a “Technical Difficulty Factor” has been defined as follows:

The above formula gives a first indication of how demanding and ambitious the generator design in question will be. For comparison purposes, some actual figures are given below:

Max. Output Speed TDF
GUANGZHOU (China) 380 MVA 500 rpm 190
WEHR (Germany) 300 MVA 600 rpm 180
SILZ (Austria) 352 MVA 500 rpm 176
FRADES II (Portugal) 433 MVA 375 rpm 162
HELMS (USA) 448 MVA 360 rpm 161
BATH COUNTY (USA) 557 MVA 257 rpm 143
RODUND II (Austria) 345 MVA 375 rpm 129
RACCOON MTN. (USA) 425 MVA 300 rpm 128
XILUODU (China) 856 MVA 125 rpm 107
AKKOY II (Turkey) 135 MVA 750 rpm 101
GURI (Venezuela) 805 MVA 112 rpm 90
WUDONGDE (China) 945 MVA 91 rpm 86
ITAIPU 50 Hz (Paraguay) 824 MVA 91 rpm 75
GRAND COULEE (USA) 826 MVA 86 rpm 71
SANXIA (China) 840 MVA 75 rpm 63

Large hydro generators and synchronous condensers are of salient-pole design. For comparison the TDF figure of a synchronous condenser unit is given below:

Max. Output Speed TDF
RIEL (Canada) 250 MVA 1,200 rpm 300

Technical data courtesy of VOITH HYDRO.

STATUS: November 30, 2016


One important design characteristic is the “MVA per pole” figure. The table below shows some values derived from high output generators built by VOITH HYDRO:

Max. Output Speed MVA per Pole
GUANGZHOU (China) 380 MVA 500 rpm 31.7
WEHR (Germany) 300 MVA 600 rpm 30.0
SILZ (Austria) 352 MVA 500 rpm 29.3
FRADES II (Portugal) 433 MVA 375 rpm 27.1
HELMS (USA) 448 MVA 360 rpm 22.4
RODUND II (Austria) 345 MVA 375 rpm 21.6
BATH COUNTY (USA) 557 MVA 257 rpm 19.9
XILUODU (China) 856 MVA 125 rpm 17.8
RACCOON MTN. (USA) 425 MVA 300 rpm 17.7
AKKOY II (Turkey) 135 MVA 750 rpm 16.9
WUDONGDE (China) 945 MVA 91 rpm 14.3
GURI (Venezuela) 805 MVA 112 rpm 12.6
ITAIPU 50 Hz (Paraguay) 824 MVA 91 rpm 12.5
SANXIA (China) 840 MVA 75 rpm 10.5
GRAND COULEE (USA) 826 MVA 86 rpm 9.8

Large hydro generators and synchronous condensers are of salient-pole design. For comparison the MVA per pole figure of a synchronous condenser unit is given below:

Max. Output Speed MVA per Pole
RIEL (Canada) 250 MVA 1,200 rpm 41.7

Technical data courtesy of VOITH HYDRO.

As can be seen from the data above, the practical range for high output hydro generators is between 10 MVA per pole (low speed units) and 30 MVA per pole (high speed units).

STATUS: November 30, 2016


Loss evaluations nowadays form an important part of all bid specifications. Based on the utilities energy price per kilowatt-hour and some other factors, the generator losses of every bid are to be multiplied with the loss evaluation figure and added to the generator bid price. One can, therefore, regard such loss evaluation as a fine: The higher the losses, the higher the penalty. In other words: A high-efficiency generator design can in some cases compensate for a moderately high bid price.

Recent bid documents specified loss evaluation values as follows:

In one particular case a loss evaluation of US$ 17,000 per kilowatt was specified. The utility may have arrived at this figure as follows:

Cost per kilowatt-hour 8.0 cents
Generator service life 40 years
Plant factor 60 percent
US$ 0.08 x 40 years x 24 hours x 365 days x 0.6 = US$ 16,820

For comparison: In Germany the average residential customer is presently being charged about Eurocents 30 per kilowatt-hour.

To illustrate the importance of loss evaluation, an example of a fictional bid evaluation can be viewed by clicking HERE.

STATUS: November 30, 2016


One of the parameters for a hydro power station that reflects its performance, and key input into the design process, is the plant factor, also known as capacity factor. The plant factor is the ratio of mean annual output (over a number of years of operation) of a power station to its maximum annual output if it operates at full capacity for the whole year.

The following table contains information published on the internet by the U.S. Bureau of Reclamation (

GRAND COULEE (Currently installed capacity 6,809 MW)

Year Net generation (Billion kWh) Plant factor (percent*)
2000 22.849 38.3
2001 14.698 24.6
2002 20.215 33.9
2003 19.171 32.1
2004 18.702 31.4
2005 20.683 34.7
2006 21.968 36.8
2007 21.859 36.6
2008 21.891 36.7
2009 18.633 31.2
2010 17.247 28.9
2011 24.609 41.2
2012 26.468 44.3
2013 21.082 35.3
2014 20.247 33.9
2015 18.927 31.7
Average plant factor: 34.5

* The plant factors in the table above are based on a plant output of 6,809 MW.

In comparison with other run-of-river plants, a plant factor of 34.5 percent seems to be low. It must be noted, however, that the main role of the GRAND COULEE hydroelectric plant is to supply peak power, not base power.

The following table contains information published on the internet by ITAIPU BINACIONAL (

ITAIPU (Final installed capacity 14,000 MW)

Year Net generation (Billion kWh) Plant factor (percent*)
2007 90.620 82.1
2008 94.685 85.6
2009 91.651 83.0
2010 87.970 79.7
2011 92.246 83.6
2012 98.287 88.8
2013 98.630 89.4
2014 87.800 79.5
2015 89.500 81.1
Average plant factor: 83.6

* The plant factors in the table above are based on a plant output of 12,600 MW. Twenty generating units are installed at ITAIPU but only 18 of them are permitted to run simultaneously. The remaining two units are acting as reserve in case unscheduled outages arise.

The following table contains information published on the internet by CHINA THREE GORGES CORPORATION (

SANXIA (Final installed capacity 22,500 MW)

The anticipated annual electricity production for the SANXIA power plant has been originally estimated to be about 84.700 Billion kilowatt-hours. With 26 generators of 700 MW each, one arrives at a plant factor of about 53 percent.

During the power plant construction phase in 2002, a decision was made to add 6 generators, 700 MW each, to the project. These generators were installed in an underground powerhouse with the intention of using them as peaking units and for generating additional power during the flood season.

The last and final generating unit was integrated into the SANXIA hydropower plant in the end of May 2012, thus completing the project. It is interesting to note that the stator windings of two of these 700 MW generators (units 27 and 28, built by DFEM) incorporated a novel evaporative cooling system.

The addition of these six 700 MW generators, together with 2 power plant auxiliary generators of 50 MW each, raised the installed power plant capacity to 22,500 MW.

Year Net generation (Billion kWh) Plant factor (percent*)
2012 98.100 49.6
2013 83.270 42.2
2014 98.800 50.1
2015 87.000 44.1
Average plant factor: 46.5

* The plant factors above are based on a plant output of 22,500 MW.

As one can assume from the plant figures above, the Parana River, where the ITAIPU power plant is located, most likely has a more uniform water flow all year round than the Yangtze River. During winter time, the water flow of the Yangtze River in the vicinity of SANXIA can drop to 3,500 cubic metres per second and the utility may reduce generation figures down to 3,000 MW for best utilization of inflow and head.

STATUS: January 31, 2016


There is a controversy on which electric power plant is the largest in the world. The answer is two-fold. The SANXIA hydropower plant is by far the largest power plant in the world based on the installed generation capacity of 22,500 MW. However, when the generated output comes into play, this merit is not easy to allocate. The last generating unit at the ITAIPU power plant has been declared operational in March 2007. From 2007 until 2015 the average annual generation amounted to 92.376 Billion kilowatt-hours and the highest generation achieved was in 2013, when 98.630 Billion kilowatt-hours were generated at ITAIPU.

For SANXIA the average annual generation from 2012 until 2015 was 91.793 Billion kilowatt-hours and the highest generation achieved was in 2014, when 98.800 Billion kilowatt-hours were generated at SANXIA. The average annual generation figures of ITAIPU and SANXIA are quite comparable, with a slight edge on ITAIPU.

STATUS: January 31, 2016


According to the 2016 Hydropower Status Report of "International Hydropower Association" (IHA), the world’s total installed hydro capacity on December 31, 2015 was geographically distributed as follows:

Region Installed Hydro Capacity
(without pumped-storage)
North America (incl. Mexico) 170,774
South & Central America 158,274
Europe 167,455
South and Central Asia (incl. Russia and Turkey) 160,430
Africa 28,067
East Asia and Pacific (incl. China) 369,479
Australia/New Zealand 13,304
World Total 1,067,783

According to the 2016 Hydropower Status Report of "International Hydropower Association" (IHA), the world’s hydroelectricity generation for year 2015 was geographically distributed as follows:

Region 2015 Net Hydroelectric Power Generation (Billion kWh) Capacity Factor (percent)
North America (incl. Mexico) 655.910 43.8
South & Central America 708.090 51.1
Europe 599.000 40.8
South and Central Asia (incl. Russia and Turkey) 473.000 33.7
Africa 116.000 47.2
East Asia and Pacific (incl. China) 1,379.080 42.6
Australia/New Zealand 37.920 32.5
World Total 3,969.000 42.4

Some may view the above listed capacity factors of hydroelectric generation to be low. However, one has to bear in mind that most of the reservoir-linked hydro power plants deliver very valuable peak power.

According to IHA the leading countries in hydro generation in 2015 were as follows:

Country 2015 Net Hydroelectric Power Generation (Billion kWh)
China 1,126.400
Brazil 382.060
Canada 375.630
USA 250.150
Russian Federation 160.170
Norway 139.000
India 124.650
Japan 91.270
Venezuela 79.500
Sweden 73.930

By the end of 2015, China was the world leader in installed hydro capacity, followed by Brazil, USA and Canada. The leading countries are as follows:

Country Installed Hydro Capacity
(without pumped-storage)
per IHA (MW)
China 296,310
Brazil 91,620
USA 79,314
Canada 79,025
Russia 49,264
India 46,708
Norway 29,215
Turkey 25,886
Japan 22,268
France 18,412
Sweden 16,320
World Total 1,067,783

It must be pointed out in this context that the statistical data published by various organizations can differ considerably from each other. Some data include pumped-storage installations which must not be treated as genuine hydropower generation plants as they only convert energy originally generated by other means. Other statistics differentiate between public utilities, private utilities and industry. To make matters statistically even more complicated: The MALTA hydropower plant in Austria, for instance, has four generating units installed. Two units are coupled to a Pelton wheel of 182,500 kW each and the other two units are each connected to a 182,500 kW Pelton wheel and to pump impellers of 145,000 kW each. The question arises whether the pumped-storage power portion of the MALTA power plant amounts to 290 MW pumping or to 365 MW generating. The total generating capacity of the MALTA power plant amounts to 730 MW, of course.

It is a less-known fact that the GRAND COULEE plant has six pumps of 48.47 MW each installed for a total pumping capacity of 290 MW. The generating capacity of these units amount to 314 MW.

For some statistics it is unclear whether they include small hydro or not.

According to REN21, the small hydro definition varies by country as follows:

Sweden < 1.5 MW
Norway < 10 MW
India < 25 MW
Brazil and U.S. < 30 MW
Canada and China < 50 MW

STATUS: April 30, 2016



According to data supplied by the German Grid Control Agency (Bundesnetz-Agentur), the total generation capacity of all German hydro power plants (including micro power plants, but excluding pumped-storage plants) by November 16, 2016 amounted to 6,148 MW. The hydro energy net production reported by the Fraunhofer Institute ISE for 2015 was 20.24 Billion kilowatt-hours, which therefore represents a capacity factor of 37.6 percent. The German hydro energy production reported by the "Federal Ministry for Economic Affairs and Energy" (BMWi) amounts to 19.0 Billion kilowatt-hours in 2015, whereas the IHA publication "2016 Hydropower Status Report" mentions a figure of 24.49 Billion kilowatt-hours.

Statistics regarding German hydropower data, however, have to be looked at with caution. The 6,148 MW figure includes all bi-national installations on the border rivers like the Danube, Inn and Rhine. By international contracts their output and generation is split 50/50 between the two countries concerned, i.e. between Germany and Austria, France or Switzerland. Quite a few other hydropower plants were completely constructed on foreign soil (Austria and Luxemburg) but were financed by German utilities. These plants feed into the German grid and are regarded by some authors of statistics as German power plants.

The actual generation capacity of all hydropower plants (including micro power plants, but excluding pumped-storage plants) installed in Germany by November 16, 2016, amounted to 4,148 MW (run-of-river 3,860 MW and reservoir 288 MW).


According to data supplied by the German Grid Control Agency (Bundesnetz-Agentur), the total generation capacity of all German pumped-storage plants by November 16, 2016 amounted to 9,440 MW.

Again, statistics regarding German hydropower data have to be looked at with caution. Some pumped-storage plants have been constructed on Austrian and Luxemburg soil but were financed by German utilities and are - by contract - feeding their electrical energy into the German grid.

The actual generation capacity of all pumped-storage plants installed in Germany by November 16, 2016, amounted to 6,357 MW. At first glance this is an impressive figure. But when all German pumped-storage reservoirs of about 37,000 MWh capacity are topped-up, it takes slightly less than 6 hours to discharge this amount of energy. Once the reservoirs are exhausted, other replacement sources for 6,357 MW have to be found.


By the end of 2010 the total generation capacity of the 17 nuclear power plants installed in Germany was 21,517 MW. In 2010, the energy production in these plants amounted to 140.5 Billion kilowatt-hours, representing a capacity factor of 74.3 percent. The tsunami-related Fukushima accident on March 11, 2011 prompted the German Government to shut down 6 reactors and to deactivate two more reactors due to repairs of conventional components (main transformer and switchyard). Re-commissioning was stopped by legal action. One more reactor of 1,275 MW was de-commissioned end of June, 2015. The remaining 8 reactors currently represent an output of 10,800 MW but a total of 10,717 MW reliable nuclear generation was lost.

The nuclear energy generation (net) in 2015 amounted to 87.070 Billion kilowatt-hours, representing an average capacity factor of about 86.9 percent.


By the end of 2015 the total generation capacity of all wind power plants installed amounted to a staggering 41,360 MW, (38,570 MW onshore and 2,790 MW offshore). The German grid consortium is publishing wind generation data on website

It is possible to review past wind-generation data by activating the calendar link on the top, by selecting the desired day.

The wind energy production (net) in 2015 amounted to 85.43 Billion kilowatt-hours, representing an average capacity factor of about 24.5 percent.


By the end of 2015 the total generation capacity of all solar (photovoltaic) power plants installed amounted to 39,550 MW. The German grid consortium is publishing solar generation data on website

It is possible to review past solar-generation data by activating the calendar link on the top, by selecting the desired day.

The solar energy production (net) in 2015 amounted to 36.580 Billion kilowatt-hours, representing an average capacity factor of about 10.7 percent.


The German Fraunhofer Institute ISE

does publish electricity production data in Germany on a daily basis under

From the charts published, the following information can be extracted:

The highest ever wind power generation was recorded on December 21, 2015 at 23:45 hours when 34,430 MW were generated.

The highest ever solar power generation occurred on April 21, 2015 at 13:15 hours, when 25,930 MW were generated.

The highest combined wind and solar power was recorded on May 09, 2016 at 13:00 hours, when 43,840 MW were generated.


German law EEG 2014 specifies the preferred acceptance of renewable electric power into the grid, regardless of consumers demand. Producers of renewable power are guaranteed fixed energy payments of up to 12.3 Eurocents per kilowatt-hour (solar) or 8.5 Eurocents per kilowatt-hour (wind). The consumers, in turn, have to subsidize this by paying a premium of 6.35 Eurocents per kilowatt-hour (2016 figures). In 2017 this figure will rise to 6.88 Eurocents.

The European Energy Exchange (EEX) is a marketplace for the trading of electrical energy generated in Germany. Electrical energy is being traded either on the spot market or futures market. The volatility of wind and solar energy does result in certain variations of energy costs. Lack of regenerative energy (wind and solar) on July 21, 2014 at 11:30 hours was responsible for a short-term cost of 12.5 Eurocents per kilowatt-hour at the EEX. In contrast, on May 08, 2016, the German grid was unable to absorb an extreme surplus of renewable generation and the prices per kilowatt-hour went into negative territory. Neighboring countries were prepared to accept electrical energy only by being paid a premium of up to 17.8 Eurocents per kilowatt-hour on top of the electrical energy delivered. The lowest weighted average price was minus 24.2 Eurocents per kWh that day with a peak of minus 37.4 Eurocents per kWh between 14:30 and 14:45 hours. On average, in 2015, one kilowatt-hour was traded at the EEX at a mere 3.5 Eurocents.

Bearing all the above in mind it is quite understandable that the average residential consumer in Germany is increasingly critical of the political wisdom of his government, as he is presently being charged about 30 Eurocents per kilowatt-hour.

STATUS: May 31, 2016


According to the German Fraunhofer Institute ISE, by the end of 2015, the installed electricity generation capacity in Germany amounted to 182,860 MW. For the same year, the same source reported an annual electricity generation in Germany of 559.22 Billion kilowatt-hours (see table below):

Hydro 20.24 Billion kilowatt-hours
Biomass 56.57 Billion kilowatt-hours
Nuclear 87.07 Billion kilowatt-hours
Brown coal 139.44 Billion kilowatt-hours
Hard coal 103.94 Billion kilowatt-hours
Gas 29.95 Billion kilowatt-hours
Wind 85.43 Billion kilowatt-hours
Solar 36.58 Billion kilowatt-hours
Total 559.22 Billion kilowatt-hours

In addition, a total of 13.85 Billion kilowatt-hours was imported from France, the Denmark and Sweden, but 60.24 Billion kilowatt-hours were exported to Austria, Switzerland, the Netherlands and Poland.

The peak electrical generation figure in 2015 occurred on April 15 at 13:00 hours, when a total of 85,930 MW was generated. The German consumption figure was 75,230 MW, because 10,700 MW were exported to neighboring countries at this time.

STATUS: April 30, 2016


Not really.

According to the 2016 Hydropower Status Report of "International Hydropower Association", the total global pumped-storage capacity by the end of 2015 amounted to 144,465 MW. The leading countries according to IHA at this date were as follows:

Japan 27,637 MW
China 23,060 MW
USA 22,441 MW
Italy 7,555 MW
France 6,985 MW
Germany 6,806 MW
Spain 5,268 MW
Austria 5,200 MW
India 4,786 MW
South Korea 4,700 MW

As mentioned above, IHA determines the world’s total installed pumped-storage capacity at the end of 2015 to 144,465 MW. This is 2.4 percent of the global generation capacity of about 6,000,000 MW and about 13.5 percent of the global hydro capacity of 1,067,783 MW.

As pointed out in the previous chapter, the power swing of wind generation plus solar generation in Germany over one day can easily reach, and even exceed, 30,000 MW. In case of calm and cloudy weather situations in Germany, thermal power plants in Germany have to fill this 30,000 MW gap. Fast reacting gas power plants can step in, if the required output is available. Otherwise fossil power plants must be activated, but their boilers have to be held constantly at uneconomic stand-by temperature. As a last resort, nuclear and thermal power plants in neighboring countries have to fill the 30,000 MW shortfall.

Experts suggest to connect the Central European grid with Scandinavia. The storage capacity of Norwegian hydro power plants has been determined to be about 84 Billion kilowatt-hours and the Swedish figure is 34 Billion kilowatt-hours. Alas, it easily will take a decade to decide, design, approve and build the necessary high voltage transmission lines.

STATUS: April 30, 2016


The short scale large-number naming system has been used throughout the „Reader’s Forum“. The relationship between the name and the corresponding numeric value is as follows:

1 Billion = 1 x 109

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