Reader's Forum

1. THE WORLD´S HYDRO GENERATOR MANUFACTURERS

According to “Renewables 2021 Global Status Report” of REN21, the world's total installed hydro capacity by December 31, 2020, amounted to 1,170,000 MW (please note that this figure of the 2021 edition of REN21 doesn't include pumped-storage capacity). Converted into electrical hydro generator output, this is equivalent to about 1,300,000 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.

According to the "2021 Hydropower Status Report" of International Hydropower Association (IHA), the pumped-storage capacity at year end 2020 was 159,494 MW.

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 1900.

According to an investigation currently in progress, there are about 130 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 info@hydropower-consult.com to the above mentioned OEM list.

STATUS: June 30, 2021



2. THE SANXIA (THREE GORGES) EXPERIENCE

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 usually is well in excess of 90 Billion kilowatt-hours, depending on precipitation conditions (see 7. PLANT FACTORS).

In 1997, an order for 6 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 for all 14 units of the first project stage (left bank power house), 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 in a publication, 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 second project stage (right hand power house) consisted of 12 more units of which the stator windings of 8 generators are water-cooled and 4 generators are air-cooled.

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 6 more generators to the project. These units are installed in an underground powerhouse. The stator windings of 2 generators are water-cooled and 2 other ones are air-cooled. For the stator windings of the 2 remaining generators, the Chinese manufacturer implemented a so-called "evaporative" cooling technology. The type of refrigerant is unknown. It is also unknown whether this type of cooling is operating satisfactorily. However, all hydro generators in the plus 700 MW class ordered since SANXIA - either in operation or still in the construction phase - have been equipped with conventional air-cooling. 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.).

References:

(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.

Interesting and detailed project information can be found on the internet under https://en.wikipedia.org/wiki/Three_Gorges_Dam

The author would appreciate comments under info@hydropower-consult.com

STATUS: June 30, 2021



3. LARGE HYDRO GENERATORS MEAN LARGE NUMBERS

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

Worldwide, there are at present quite a few 600 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
BELO MONTE (Brazil) 18 units of 630 MW each

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

POWER

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

CENTRIFUGAL FORCES

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.

CIRCUMFERENTIAL SPEED

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).

WEIGHTS

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

ROTATIONAL ENERGY

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.

EARNING CAPACITY

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: August 15, 2019



4. TECHNICAL DIFFICULTY FACTOR (TDF)

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
CHANG LONG SHAN (China) 389 MVA 600 rpm 233
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: January 31, 2018



5. OUTPUT PER POLE

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
CHANG LONG SHAN (China) 389 MVA 600 rpm 38.9
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 40 MVA per pole (high speed units).

STATUS: January 31, 2018



6. LOSS EVALUATION

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: Taking into account the fixed meter charge, the average residential customer in Germany is presently being charged about 34 Eurocents per kilowatt-hour.

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

STATUS: August 15, 2019



7. PLANT FACTORS

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 (https://www.usbr.gov/):

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
2016 19.017 31.8
2017 20.996 35.2
2018 22.031 36.9
2019 16.587 27.8
2020 not available not available
Average plant factor: 34.2

* 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 xx.x 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 (https://www.itaipu.gov.br/en):

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
2016 103.098 93.2
2017 96.387 87.3
2018 96.586 87.5
2019 79.445 72.0
2020 76.382 69.0
Average plant factor: 83.0

* 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 (https://www.ctg.com.cn/en):

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. As mentioned before (see 2. THE SANXIA (THREE GORGES) EXPERIENCE) 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
2016 93.500 47.3
2017 97.600 49.5
2018 101.600 51.5
2019 96.880 49.2
2020 111.800 56.6
Average plant factor: 48.9

* 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: June 30, 2021



8. THE WORLD’S LARGEST HYDROPOWER PLANT

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 less easy to allocate. The last generating unit at the ITAIPU power plant has been declared operational in March 2007. From 2007 until 2020 the average annual generation amounted to 91.664 Billion kilowatt-hours and the highest generation achieved was in 2016, when 103.098 Billion kilowatt-hours were generated at ITAIPU.

For SANXIA the average annual generation from 2012 until 2020 was 96.506 Billion kilowatt-hours and the highest generation achieved was in 2020, when 111.800 Billion kilowatt-hours were generated at SANXIA. The average annual generation figures of ITAIPU and SANXIA therefore are comparable, but at present with a 5 percent edge in favour of SANXIA. .

STATUS: June 30, 2021



9. THE WORLD’S TOTAL INSTALLED HYDRO CAPACITY

According to the "2021 Hydropower Status Report" of International Hydropower Association (IHA), the world’s total installed hydro capacity on December 31, 2020 was geographically distributed as follows:

Region Installed Hydro Capacity
(without pumped-storage)
(MW)
North and Central America 181,779
South America 175,753
Europe (incl. Turkey) 199,578
South and Central Asia (incl. Russia) 146,670
Africa 34,797
East Asia and Pacific (incl. China) 419,232
Australia/New Zealand 12,804
World Total 1,170,612

According to the "2021 Hydropower Status Report" of International Hydropower Association (IHA), the world’s hydroelectricity generation for year 2020 (excluding pumped-storage) was geographically distributed as follows:

Region 2020 Net Hydroelectric Power Generation (Billion kWh) Capacity Factor (percent)
North and Central America 724.000 45.3
South America 690.000 44.7
Europe (incl. Turkey) 674.000 38.4
South and Central Asia (incl. Russia) 498.110 38.7
Africa 139.540 45.7
East Asia and Pacific (incl. China) 1,604.130 43.6
Australia/New Zealand 38.870 34.6
World Total 4,370.000 42.5

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. One has also bear in mind, that the installed pumped-storage capacity is excluded in the above power generation figures.

According to IHA the leading countries in hydro generation in 2020 (excluding pumped-storage) were as follows:

Country 2020 Net Hydroelectric Power Generation (Billion kWh)
China 1,355.200
Brazil 409.500
Canada 383.000
USA 291.000
Russian Federation 196.000
India 155.000
Norway 141.690
Japan 89.170
Turkey 77.390
Venezuela 72.000

By the end of 2020, China was the world leader in installed hydro capacity, followed by Brazil, Canada and USA. The leading countries are as follows:

Country Installed Hydro Capacity
(without pumped-storage)
per IHA (MW)
China 338,670
Brazil 109,241
Canada 81,823
USA 79,145
Russia 48,527
India 45,763
Norway 31,556
Turkey 30,984
Japan 22,379
France 19,671
Vietnam 17,111
Sweden 16,379
World Total 1,170,612

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: June 30, 2021



10. COMPARISON OF HYDRO, PUMPED-STORAGE, NUCLEAR, WIND, SOLAR AND BIOMASS POWER IN GERMANY


HYDRO

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 January 19, 2021 amounted to 4,856 MW. The hydro energy net production reported by the Fraunhofer Institute ISE for 2020 was 18.30 Billion kilowatt-hours, which therefore represents a capacity factor of 42.9 percent. The German hydro energy production reported by the Federal Ministry for Economic Affairs and Energy (BMWi), amounts to 18.60 Billion kilowatt-hours in 2020, whereas the IHA publication "2021 Hydropower Status Report" mentions a figure of 24.75 Billion kilowatt-hours for 2020.

Statistics regarding German hydropower data have to be looked at with caution. The 4,856 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 and 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 January 19, 2021, amounted to 3,916 MW (run-of-river 3,618 MW and reservoir 298 MW).

PUMPED-STORAGE

According to data supplied by the German Grid Control Agency (Bundesnetz-Agentur), the total generation capacity of all German pumped-storage plants by January 19, 2021 amounted to 9,654 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 and in operation in Germany by January 19, 2021, amounted to 6,199 MW. At first glance this is an impressive figure. But when all German pumped-storage reservoirs of about 37,200 MWh capacity are topped-up, it takes 6.0 hours to discharge this amount of energy. Once the reservoirs are exhausted, other replacement sources have to be found.

NUCLEAR

By the end of 2000 the total generation capacity of the 19 nuclear reactors installed in Germany was 22,365 MW, according to Kerntechnik Deutschland e.V. In 2000, the energy production in these plants amounted to 169.7 Billion kilowatt-hours, representing a capacity factor of 86.4 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. Additional reactors were decommissioned the years after. According to VGB PowerTech, January 2021, the remaining 6 reactors currently represent an output of 8,545 MW but a total of 13,820 MW reliable nuclear generation was lost.

According to data supplied by the Fraunhofer Institute ISE, the nuclear energy production (net) in 2020 amounted to 60.90 Billion kilowatt-hours, representing an average capacity factor of about 81.1 percent.

WIND

By the end of 2020 the total generation capacity of all wind power plants installed amounted to a staggering 62,400 MW, (54,600 MW onshore and 7,800 MW offshore).

According to data supplied by the Fraunhofer Institute ISE, the wind energy production (net) in 2020 amounted to 132.00 Billion kilowatt-hours, representing an average capacity factor of about 24.1 percent.

SOLAR

By the end of 2020 the total generation capacity of all solar (photovoltaic) power plants installed amounted to 53,600 MW.

According to data supplied by the Fraunhofer Institute ISE, the solar energy production (net) in 2020 amounted to 50.70 Billion kilowatt-hours, representing an average capacity factor of about 10.8 percent.

BIOMASS

A substantial amount of electricity generation originated from biomass. According to data supplied by the German Grid Control Agency (Bundesnetz-Agentur) the total generation capacity of all biomass power plants installed by January 19, 2021 amounted to 8,600 MW.

According to data supplied by the Fraunhofer Institute ISE, the biomass energy production (net) in 2020 amounted to 45.50 Billion kilowatt-hours, representing an average capacity factor of about 60.2 percent.

WIND AND SOLAR POWER PEAK FIGURES

The German Fraunhofer Institute ISE

https://www.ise.fraunhofer.de/en

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

https://energy-charts.info/?l=en&c=DE

Select "Power" and "Electricity Production" and various interactive graphs are available. From the charts published, the following information can be extracted:

The highest wind power generation was recorded on February 22, 2020 at 20:30 hours when 46,900 MW were generated.

The highest solar power generation occurred on June 01, 2020 at 13:00 hours, when 37,250 MW were generated.

The highest combined wind and solar power was recorded on August 26, 2020 at 13:30 hours, when 64,250 MW (wind 44,230 MW and solar 20,020 MW) were generated.

RENEWABLE ENERGY SOURCES ACT EEG 2014

German law EEG 2014 specifies the preferred acceptance of renewable electric power into the grid, regardless of consumers demand. Producers of renewable power were guaranteed fixed energy payments per kilowatt-hour. The consumers, in turn, had to subsidize this by paying additionally a premium of 6.756 Eurocents per kilowatt-hour (2020 figure).

The European Energy Exchange (EEX) is a marketplace for the trading of electrical energy generated in Europe. 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) always is responsible for high short-term costs at the EEX. But in case the German grid is unable to absorb an extreme surplus of renewable generation, the prices per kilowatt-hour enter into negative territory. Neighboring countries then are prepared to accept electrical energy only by being paid a premium on top of the electrical energy delivered. On average, in 2020, one kilowatt-hour future baseload was traded at the EEX at a mere 4.2 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 32 Eurocents per kilowatt-hour, plus a monthly electricity meter charge.

Under these circumstances here another fact, not easy to understand: The highly efficient 1,600 MW hard coal power plant "Moorburg" near Hamburg became operational in 2015, with an additional 650 MW district heating capacity. Despite a construction cost of 3 Billion Euro, this plant was decommissioned for scrap in December 2020, instead of decommissioning low efficient and dirty brown coal power plants in other locations.

STATUS: June 30, 2021



11. TOTAL ELECTRICAL CAPACITY AND GENERATION IN 2020 IN GERMANY

According to the Federal Network Agency (BNetzA), by the end of 2020, the in service electricity generation capacity in Germany amounted to 213,535 MW. For the same year, the German Fraunhofer Institute ISE reported an annual net electricity generation in Germany of 487.80 Billion kilowatt-hours (see table below):

Hydro 18.30 Billion kilowatt-hours
Biomass 45.50 Billion kilowatt-hours
Nuclear 60.90 Billion kilowatt-hours
Brown coal 82.00 Billion kilowatt-hours
Hard coal 35.60 Billion kilowatt-hours
Gas 59.10 Billion kilowatt-hours
Wind 131.70 Billion kilowatt-hours
Solar 50.70 Billion kilowatt-hours
Others 4.00 Billion kilowatt-hours
 
Total 487.80 Billion kilowatt-hours

About 18.00 TWh were exported in 2020 to neighboring countries.

The peak electrical generation figure in 2020 occurred on March 13 at 12:30 hours, when a total of 88,700 MW was generated. The German consumption figure was 70,200 MW, because 12,700 MW were exported to neighboring countries and 4,300 MW were consumed by pumped-storage plants at this time. About 1,500 MW are not accounted for.

STATUS: June 30, 2021



12. PUMPED-STORAGE: THE ANSWER FOR ENERGY STORAGE?


Not really.

According to the "2021 Hydropower Status Report" of International Hydropower Association, the total global pumped-storage capacity by the end of 2020 amounted to 159,494 MW. The leading countries according to IHA at this date were as follows:

China 31,490 MW
Japan 27,637 MW
USA 22,855 MW
Italy 7,685 MW
France 5,837 MW
Germany 6,364 MW
Spain 6,117 MW
Austria 5,596 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 2020 to 159,494 MW. This is 2.2 percent of the global generation capacity of about 7,350,000 MW and about 13.6 percent of the global hydro capacity of 1,170,612 MW.

In order to replace thermal and nuclear power plants, some German organizations strongly recommend to multiply the currently installed wind and solar capacity up to five times. In this context, however, one has to bear in mind, that solar energy is available only at daylight and that wind output figures in Germany occasionally drop to as little as 2,000 MW. At 12:30 hours on March 13, 2020, for instance, nature generated a total of 60,940 MW (wind 41,930 MW and solar 19,010 MW). Only 13 hours later the combined wind and solar generation of 60,940 MW dropped to a figure of below 5,000 MW for a duration of more than five hours and only a minimum generation of 2,200 MW was available at 05:00 hours on March 14. Under these conditions even a five times multiple installed wind and solar installation wouldn't have protected Germany from a total blackout, fortunately thermal and nuclear power plants were still able to step in this day.

As mentioned above, the power swing of wind generation plus solar generation in Germany over one day can easily reach, and even exceed, 50,000 MW. Even if all neighboring countries of Germany are asked to step in, a power swing of this magnitude is beyond their combined pumped-storage capacity. In case of calm and cloudy weather situations in Germany, thermal power plants in Germany have to fill this 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 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. On closer examination reality has out-dated experts advice: In April 2021 the 1,400 MW NordLink HVDC submarine cable - costing a total of 2 Billion Euro - commenced operation between Norway and Germany. This project went through realization despite the fact that Norway has too little pumped-storage capacity to absorb a substantial amount of excess wind energy from Northern Germany. Also, because electric car sales are hitting record levels in Norway, electricity consumption is rising to such an extent, that there is little energy available for export.

STATUS: June 30, 2021



Attention:

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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