The THEMIS

solar power tower A solar power tower, also known as 'central tower' power plant or 'heliostat' power plant, is a type of solar furnace using a tower to receive focused sunlight. It uses an array of flat, movable mirrors (called heliostats) to focus the sun's ra ...

is a

research and development Research and development (R&D or R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products, and improving existi ...

centre focused on

solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...

. It is located near the village of

Targasonne Targasonne (; ca, Targasona; before 2022: ''Targassonne'') is a commune of Cerdanya in the Pyrénées-Orientales department in south of France. Targasonne is the home of the THEMIS Solar Power R&D Center. Geography Targasonne is located in t ...

, in the department of

Pyrénées-Orientales Pyrénées-Orientales (; ca, Pirineus Orientals ; oc, Pirenèus Orientals ; ), also known as Northern Catalonia, is a department of the region of Occitania, Southern France, adjacent to the northern Spanish frontier and the Mediterranean Sea. ...

, south of France, 3 kilometres from the world's largest

solar furnace A solar furnace is a structure that uses concentrated solar power to produce high temperatures, usually for industry. Parabolic mirrors or heliostats concentrate light (Insolation) onto a focal point. The temperature at the focal point may rea ...

Odeillo Font-Romeu-Odeillo-Via (; ca, Font-romeu, Odelló i Vià), or simply Odeillo, is a commune in the Pyrénées-Orientales and Cerdagne near the Spanish border in the south of France. It comprises the villages of Odeillo and Via, as well as Font-Ro ...

Siting of the plant

THEMIS

, owned by the

General Council of the Pyrénées-Orientales A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". OED O ...

, was strategically located in the region of

Cerdanya Cerdanya () or often La Cerdanya ( la, Ceretani or ''Ceritania''; french: Cerdagne; es, Cerdaña), is a natural comarca and historical region of the eastern Pyrenees divided between France and Spain. Historically it was one of the counties ...

, in the

, because the conditions are excellent for

. 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 The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

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 development Research and development (R&D or R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products, and improving existi ...

is focused on solar energy, and THEMIS is a research facility as well as a photovoltaic power facility and a solar thermal energy plant.

THEMIS solar thermal energy

The plant had a power output of 2 MW in 1983. It was based on an array of 201 mirrors which heated a cavity receiver (a cavity lined with coolant tubes) at the top of a 100 m tower where the

coolant A coolant is a substance, typically liquid, that is used to reduce or regulate the temperature of a system. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, chemically inert and neither causes nor promotes corrosio ...

(molten salts) carried the thermal energy to a steam generator, itself powering an electric turbine. The molten salts were

potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and nitrat ...

(53%),

sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite ...

(40%) and

sodium nitrate Sodium nitrate is the chemical compound with the formula . This alkali metal nitrate salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile) to distinguish it from ordinary saltpeter, potassium nitrate. T ...

(7%). The coolant entry temperature was 250 °C and the exit temperature 450 °C. Steam was produced in the generator 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 franc The franc (, ; sign: F or Fr), also commonly distinguished as the (FF), was a currency of France. 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. It w ...

s (about 45 million euros), and was operated and managed by

Électricité de France Électricité de France S.A. (literally ''Electricity of France''), commonly known as EDF, is a French multinational electric utility company, largely owned by the French state. Headquartered in Paris, with €71.2 billion in revenues in 2 ...

(EDF). The plant went into hibernation for more than twenty years, and turned into a scientific facility of the

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...

, and the

Commissariat à l'énergie atomique The French Alternative Energies and Atomic Energy Commission or CEA ( French: Commissariat à l'énergie atomique et aux énergies alternatives), is a French public government-funded research organisation in the areas of energy, defense and securit ...

focusing on

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...

, with an open air Cherenkov Telescope, measuring

gamma rays A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

hitting the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

(see

IACT IACT stands for Imaging Atmospheric (or Air) Cherenkov Telescope or Technique. It is a device or method to detect very-high-energy gamma ray photons in the photon energy range of 50 GeV to 50 TeV. There are four operating IACT systems: ...

). In 2004, a rehabilitation program was devised by the

, to produce power, and create a research and development centre on

with the

Centre national de la recherche scientifique The French National Centre for Scientific Research (french: link=no, Centre national de la recherche scientifique, CNRS) is the French state research organisation and is the largest fundamental science Basic research, also called pure research o ...

(

CNRS The French National Centre for Scientific Research (french: link=no, Centre national de la recherche scientifique, CNRS) is the French state research organisation and is the largest fundamental science agency in Europe. In 2016, it employed 31,637 ...

), and Tecsol, a local engineering office. THEMIS still has its 201 sun-following devices called

heliostat A heliostat (from ''helios'', the Greek word for ''sun'', and ''stat'', as in stationary) is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating ...

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

towards the hot spot at the top of the 104 m central tower, where the receiver was originally placed (which is now part of the exhibition outside the Odeillo

). The heliostats are, however, no longer operational. The three rows of heliostats furthest away from the tower are having their mirrors replaced by

solar cell A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

s. Of these cells, some will follow the sun while others will not, so as to measure the difference in efficiency. The

rehabilitation project has repaired half of the heliostats in order to develop a power of 1 MWe, by means of a

gas turbine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...

installed at the top of the tower, fed either with hot air directly from an air receiver (PEGASE project) or a receiver with particles which also serves to store thermal energy: European projec
Next-CSP project website
2017-2021. In April 2018, a new research project started at the THEMIS tower
the POLYPHEM project ("Small-Scale Solar Thermal Combined Cycle")POLYPHEM
is a

Horizon 2020 The Framework Programmes for Research and Technological Development, also called Framework Programmes or abbreviated FP1 to FP9, are funding programmes created by the European Union/European Commission to support and foster research in the Europea ...

project funded under the Energy programme
LCE-07-2016-2017
- Developing the next generation technologies of renewable electricity and heating/cooling). The consortium is coordinated by th
CNRS-PROMES
lab and implemented by a total of 9 partners from 4 EU member countries. The project will end in March 2022 and has a budget of 4,975 M€ (EC grant) over these 4 years
POLYPHEM
aims at improving the flexibility and the performance of small-scale Concentrated Solar Power plants, thanks to a solar-driven micro gas-turbine technology. As a final result, the project will build a 60 kW prototype plant with a 1,3 MWh thermal storage unit and will validate this innovative power cycle in a relevant environment (TRL 5), at the Themis solar tower in Targassone.

References

External links