A powership is an existing ship that has been modified for power generation, a marine vessel, on which a power plant is installed to serve as a power generation resource. Converted from existing ships, powerships are self-propelled, ready to go infrastructure for developing countries that plug into national grids where required. Unmotorised powerships, known as power barges, are power plants installed on a deck barge. These are sometimes called "floating power plants" or "barge mounted power plants". They were initially developed during World War II by General Electric for the War Production Board as a transportable large-scale power generation resource.
Powerships or power barges can be equipped with single or multiple gas turbines, reciprocating diesel and gas engines, boilers or nuclear reactors for electricity generation. Bureau Veritas, an international certification agency with experience in overseeing both shipbuilding and power plant development, classifies such floating power plants as "special service power plants".
One of the earliest (if not the first) powership built was in 1931, the SS Jacona, built by the Newport News, Virginia Shipyard and Drydock Company, for the New England Public Service Company of Augusta, Maine. The idea came to the president of the Augusta firm, when one winter a severe winter storm took out a lot of the New England major power transmission lines. The Jacona role would be to dock as near as possible to the affected area and hook into the local power grid, restoring power. During the summer months the Jacona would hook into vacation area power grids where power needs are extremely low during off season and extremely high during the summer vacation season. The Jacona was fitted with steam boilers which drove two generators which could produce 10,000 kW each.
At one time the US Navy used its submarines when disaster hit a local community that brought down the commercial power grid, which led to the idea of powerships for the US Navy, and an early US Navy powership was the USS Saranac, a former US Navy naval ship. Saranac was a 1942 built fleet oiler before her conversion into a powership following the Second World War to serve in the US Navy and Army. In 1957, she was sold to Hugo Neu Corporation of New York City and was used then as a power facility abroad by the International Steel and Metal Corporation. In 1959, she was renamed Somerset.
The first floating nuclear reactor ship was the MH-1A, in the Panama canal zone. This ship (the Sturgis) is due to be scrapped in 2015. Although the reactor and fuel have already been removed.
Power barges and power ships offer a number of advantages over other forms of power plants; due to their mobility, powerships can be connected to local power grids to temporarily cover demands whenever on site power plants are insufficient or the building of new power plants will take time, while dual-fuel engines on board can be powered by either liquid fuels or gas. The power barge and power ship are able to use any infrastructure available at the site on which she is required.
Some recently built power ships are existing large bulk carriers, which are fitted with used reciprocating engines and new state-of-the-art, large-bore dual-fuel diesel engines that run on heavy fuel or natural gas to generate electricity, relevant transformers and electric switchboards. The only other power ships were based on US Naval vessels. Power ships utilizing new purpose built ships would not be competitive to a purpose built power barge due to the higher cost of construction. The crew quarters and propulsion systems are under utilized during the power plant operational period which can be up to the life of the power plant.
It is expected that a power barge or power ship could moor at one place for an average duration of three to five years on a lease, or up to 20 years under a PPA. For this reason, power ships if constructed already, are a solution to bridge the gap for a certain time until a local power plant is built or the high demand in electricity supply is over.
Karadeniz Powership Co. Ltd., a subsidiary of Karadeniz Energy Group based in Turkey, developed and carries out a project named "Power of Friendship" that aims to provide a total of 2,010 MW of electricity to more than ten shortage-stricken countries in the Middle East, northern Africa and southern Asia with ten different ships by the end of 2010. The first powership of the project, which can supply 144 MW power, went into service at the beginning of 2010 off the shore near Basra in south-eastern Iraq, and the second powership is on its way to the same place. The company also signed a contract with Pakistan, but the Pakistani government terminated this project. This case in now being heard in the World Bank Tribunal.
All other builders of power ships have gone out of business as power barges have proved to be more cost effective.
From Bangladesh to USA
During the 1990s, power barges became a popular way of providing energy to developing nations, with companies including equipment suppliers like General Electric, Westinghouse, Wärtsilä, and MAN; by developers such as Smith Cogeneration, AES, GMR Vasavi, which operate floating power plants for customers located in New York City (USA), Khulna (Bangladesh), the Dominican Republic, Brazil, Ecuador, Angola, Nigeria, Thailand, Effassu (Ghana), as well as in the Philippines, Jamaica, Kenya and Malaysia. Engineering, procurement and construction companies such Power Barge Corporation, Waller Marine Inc, Hyundai, IHI Corporation and Mitsui offer gas turbine power barge construction programs, and Karadeniz Energy, MAN and Wärtsilä offer medium speed engine power barges.
Today there are over 75 power barges deployed and operating around the world. The utilization rate of power barges is around 95% with only one or two power barges available in the global market at any one time.
In April 2011, Waller Marine finalized installation in Venezuela of two large floating power generation barges into a prepared basin at Tacoa. The two 171 MW barges, each supporting a GE 7FA dual fuel industrial gas turbine, are connected to the grid and soon supply much needed power to Caracas. Power Barge Corporation recently delivered a 96 MW gas turbine power barge to Angola, a 72 MW Wartsila power barge to Panama and a 105 MW gas turbine power barge to Venezuela.
Year of conversion given in parenthesis.
- USS Saranac (1957)
- MV Karadeniz Powership Doğan Bey (IMO 8117031), 126 MW, 2010, serving in Basra, Iraq.
- MV Karadeniz Powership Rauf Bey (IMO 7925522), 180 MW, 2010, serving in Basra, Iraq.
- MV Karadeniz Powership Kaya Bey (IMO 7925546), 216 MW, 2011, served in Pakistan, now serving in Basra, Iraq.
- MV Karadeniz Powership Alican Bey (IMO ?), 104 MW, 2011, served in Pakistan.
- MV Karadeniz Powership Irem Sultan (IMO 8222252), 111 MW, 2012, served in Basra, Iraq, now serving in Nacala, Mozambique.
- MV Karadeniz Powership Fatmagül Sultan (IMO ?), 203 MW, 2013, serving in Beirut, Lebanon.
- MV Karadeniz Powership Orhan Bey (IMO ? ), 203 MW, 2013, serving in Beirut, Lebanon.
- MV KPS7 - Karadeniz Powership Ayşegül Sultan (IMO ? ), 235 MW, 2015, serving in Tema Harbour, Ghana.
- MV Karadeniz Powership Zeynep Sultan (IMO 8116051), 125 MW, 2015, serving in North Sulawesi, Indonesia.
Notable power barges that Power Barge Corporation has worked on
- SS Jacona (20 MW) 
- Osagyefo Barge (125 MW), located at Effasu, Ghana
- Iuka 101/102 (30 MW) Frame 6B power barges (part of a fleet of 9 power barges in Lagos) Nigeria
- Dymani III (48 MW) W251B11 Kenya
- Gantisan One (50 MW) LM2500 Malaysia
- Dynami I (105 MW) W501D5 Venezuela
- Dynami II (96 MW) W251B11 Angola
- Dynami iV (116 MW) W501D5A Ecuador
- Victoria 8 (144 MW) W251B11 CCGT Bangladesh
- Rio da Luz (100 MW) P&W FT4C-3F (decommissioned)
- Power Barge II (50 MW) MAN 51/52 Panama
- TBGMR (250 MW) LM6000PC CCGT Mangalore
- SmithEnron (185 MW) Frame 7 CCGT Dominican Republic
- Estrella Del Norte (40MW) Dominican Republic
- Estrella del Mar (72 MW) Dominican Republic
- Estrella del Mar II (108 MW) Dominican Republic
- Santa Ines (55 MW) Guatemala
- Santa Elena (55 MW) Guatemala
- MH-1A, a floating power station constructed as part of the Army Nuclear Power Program
- Russian floating nuclear power station
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- "225 Megawatts Turkish Power Barge En-route To Ghana". Ghana Broadcasting Corporation. 2015-10-27. Retrieved 2015-10-31.
- "Yüzen santraller Ayşegül Sultan Gana'ya, Zeynep Sultan Endonezya'ya uğurlandı". Deniz Haber Ajansı (in Turkish). 2015-10-27. Retrieved 2015-11-01.
- Popular Mechanics (February 1931), Floating Power Plant
- NavSource Online: Service Ship Photo Archive, Jacona (YFP-1)
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