Themis (solar power plant)
Encyclopedia
Solar power tower
The solar power tower is a type of solar furnace using a tower to receive the focused sunlight. It uses an array of flat, movable mirrors to focus the sun's rays upon a collector tower...
is a research and development
Research and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
centre focused on solar energy. It is located near the village of Targassonne
Targassonne
Targassonne is a commune of Cerdanya in the Pyrénées-Orientales department in south of France. It is located at 1,600 meters near the villages of Égat and Font-Romeu-Odeillo-Via....
, in the department of Pyrénées-Orientales
Pyrénées-Orientales
Pyrénées-Orientales is a department of southern France adjacent to the northern Spanish frontier and the Mediterranean Sea. It also surrounds the tiny Spanish enclave of Llívia, and thus has two distinct borders with Spain.- History :...
, south of France, 3 kilometres from the world's largest solar furnace
Solar furnace
A solar furnace is a structure that captures sunlight to produce high temperatures, usually for industry. This is done with a curved mirror that acts as a parabolic reflector, concentrating light onto a focal point...
in Odeillo.
Siting of the plant
THEMIS Solar power towerSolar power tower
The solar power tower is a type of solar furnace using a tower to receive the focused sunlight. It uses an array of flat, movable mirrors to focus the sun's rays upon a collector tower...
, owned by the General Council of the Pyrénées-Orientales
General Council of the Pyrénées-Orientales
The General Council of the Pyrénées-Orientales is the assembly elected for 6 years by the 31 Cantons of the Pyrénées-Orientales and its executive...
http://www.cg66.fr/, was strategically located in the region of Cerdanya
Cerdanya
Cerdanya is a natural comarca and historical region of the eastern Pyrenees divided between France and Spain. Historically it has been one of the counties of Catalonia....
, in the Pyrénées-Orientales
Pyrénées-Orientales
Pyrénées-Orientales is a department of southern France adjacent to the northern Spanish frontier and the Mediterranean Sea. It also surrounds the tiny Spanish enclave of Llívia, and thus has two distinct borders with Spain.- History :...
, because the conditions are excellent for solar energy. First, Cerdanya has almost 2400 hours of sunshine a year. Second, there is a very low wind limiting the time of disruption of the plant. Third, the site is at a high elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
providing stronger sunlight. The land chosen for the plant is on a slope between 6° and 18°, which is suitable for a power tower.
THEMIS research and development centre
Research and developmentResearch and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
is focused on solar energy, and THEMIS is a research facility as well as a photovoltaic power facility
Photovoltaic system
A photovoltaic system is a system which uses one or more solar panels to convert sunlight into electricity. It consists of multiple components, including the photovoltaic modules, mechanical and electrical connections and mountings and means of regulating and/or modifying the electrical...
and a solar thermal energy plant
Solar thermal energy
Solar thermal energy is a technology for harnessing solar energy for thermal energy . Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors. Low-temperature collectors are flat plates generally used to heat...
.
THEMIS solar thermal energy
It had a power output of 2 MW in 1983. It was based on an array of 201 mirrors which heated a boiler (a cavity lined with coolant tubes) at the top of a 100 m tower where the coolantCoolant
A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...
(molten salts) carried the thermal energy to a vapour generator, itself powering an electric turbine. The molten salts were potassium nitrate
Potassium nitrate
Potassium nitrate is a chemical compound with the formula KNO3. It is an ionic salt of potassium ions K+ and nitrate ions NO3−.It occurs as a mineral niter and is a natural solid source of nitrogen. Its common names include saltpetre , from medieval Latin sal petræ: "stone salt" or possibly "Salt...
(53%), sodium nitrite
Sodium nitrite
Sodium nitrite is the inorganic compound with the chemical formula NaNO2. It is a white to slight yellowish crystalline powder that is very soluble in water and is hygroscopic...
(40%) and sodium nitrate
Sodium nitrate
Sodium nitrate is the chemical compound with the formula NaNO3. This salt, also known as Chile saltpeter or Peru saltpeter to distinguish it from ordinary saltpeter, potassium nitrate, is a white solid which is very soluble in water...
(7%). The coolant entry temperature was 250 °C and the exit temperature 450 °C. The vapour produced in the generator was at a pressure of 50 bar and a temperature of 430 °C.
History
The first THEMIS solar plant, was an experimental solar facility which produced power between 1983 and 1986, and then closed in part due to the difficulty of managing the cooling system, and in part due to a lack of political and financial support. Construction started in 1979 at a cost of 300 million French francFrench franc
The franc was a currency of France. Along with the Spanish peseta, it was also a de facto currency used in Andorra . Between 1360 and 1641, it was the name of coins worth 1 livre tournois and it remained in common parlance as a term for this amount of money...
s (about 45 million euros), and was operated and managed by Électricité de France
Électricité de France
Électricité de France S.A. is the second largest French utility company. Headquartered in Paris, France, with €65.2 billion in revenues in 2010, EDF operates a diverse portfolio of 120,000+ megawatts of generation capacity in Europe, Latin America, Asia, the Middle East and Africa.EDF is one of...
(EDF).
The plant went into hibernation for more than twenty years, and turned into a scientific facility of the CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
, and the Commissariat à l'énergie atomique
Commissariat à l'Énergie Atomique
The Commissariat à l'énergie atomique et aux énergies alternatives or CEA, is a French “public establishment related to industrial and commercial activities” whose mission is to develop all applications of nuclear power, both civilian and military...
focusing on astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
, with an open air Cherenkov Telescope
Gamma-ray astronomy
Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays. Gamma-rays are the most energetic form of "light" that travel across the universe, and gamma-rays thus have the smallest wavelength of any wave in the electromagnetic spectrum.Gamma-rays are created by celestial events...
, measuring gamma rays hitting the atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
(see IACT
IACT
The IACT or Imaging Atmospheric Cherenkov Technique is the method whereby very high energy gamma-ray photons in the 50 GeV to 50 TeV range can be detected by ground based telescopes. There are currently four major ground based telescopes including CANGAROO III, MAGIC, HESS and VERITAS...
).
In 2004 a rehabilitation program was devised by the General Council of the Pyrénées-Orientales
General Council of the Pyrénées-Orientales
The General Council of the Pyrénées-Orientales is the assembly elected for 6 years by the 31 Cantons of the Pyrénées-Orientales and its executive...
, to produce power, and create a research and development centre
Research and development
The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...
on solar energy with the Centre national de la recherche scientifique
Centre national de la recherche scientifique
The National Center of Scientific Research is the largest governmental research organization in France and the largest fundamental science agency in Europe....
(CNRS), and Tecsol, a local engineering office.
THEMIS still has its 201 sun-following devices called heliostat
Heliostat
A heliostat is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. The target may be a physical object, distant from the heliostat, or a direction in space...
s, most of them still equipped with mirrors (53.70 m² each) covering an area of 11,800 m² in total, able to send the solar energy towards the hot spot at the top of the 104 m central tower, where the boiler was originally placed (which is now part of the exposition outside the Odeillo solar furnace
Solar furnace
A solar furnace is a structure that captures sunlight to produce high temperatures, usually for industry. This is done with a curved mirror that acts as a parabolic reflector, concentrating light onto a focal point...
). The heliostats are, however, not operational.
The three rows of heliostats furthest away from the tower are having their mirrors replaced by photovoltaic cells. Of these cells, some will follow the sun while others will not, so as to measure the difference in efficiency.
The rehabilitation project will repair half of the heliostats in order to develop a power of 1 MW, thanks to a gas turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....
installed at the top of the tower, and will replace the other half of the mirrors with solar cells.
See also
- List of solar thermal power stations
- Mont-Louis Solar FurnaceMont-Louis Solar FurnaceThe Mont-Louis Solar Furnace is an experimental solar furnace - a solar thermal energy facility that was built in 1949. It was the first facility of its kind in the world, and was a precursor of the Odeillo Solar Furnace...