astronomy

Themis (solar power plant)

Themis (solar power plant) is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Themis (solar power plant) rather than just read about it. In short: The THEMIS solar power tower is a research and development centre focused on solar energy. It is located near the village of Targasonne, in the department of Pyrénées-Orientales, south of France, 3 kilometres from the world's largest solar furnace in Odeillo.

Key takeaways

Themis (solar power plant) belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Themis (solar power plant) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Themis (solar power plant) from memory before moving on to harder problems.

Reference excerpt

The THEMIS solar power tower is a research and development centre focused on solar energy. It is located near the village of Targasonne, in the department of Pyrénées-Orientales, south of France, 3 kilometres from the world's largest solar furnace in Odeillo.

Siting of the plant THEMIS solar power tower, owned by the General Council of the Pyrénées-Orientales, was strategically located in the region of Cerdanya, in the Pyrénées-Orientales, 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 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 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 (molten salts) carried the thermal energy to a steam generator, itself powering an electric turbine. The molten salts were potassium nitrate (53%), sodium nitrite (40%) and sodium nitrate (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 francs (about 45 million euros), and was operated and managed by Électricité de France (EDF). The plant went into hibernation for more than twenty years, and turned into a scientific facility of the CERN, and the Commissariat à l'énergie atomique focusing on astrophysics, with an open air Cherenkov Telescope, measuring gamma rays hitting the atmosphere (see Cherenkov Array at Themis). In 2004, a rehabilitation program was devised by the General Council of the Pyrénées-Orientales, to produce power, and create a research and development centre on solar energy with the Centre national de la recherche scientifique (CNRS), and Tecsol, a local engineering office. THEMIS still has its 201 sun-following devices called heliostats, 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 receiver was originally placed (which is now part of the exhibition outside the Odeillo solar furnace). The heliostats are, however, no longer operational. The three rows of heliostats furthest away from the tower are having their mirrors replaced by solar cells. Of these cells, some will follow the sun while others will not, so as to measure the difference in efficiency. The CNRS rehabilitation project has repaired half of the heliostats in order to develop a power of 1 MWe, by means of a gas turbine 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 project 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 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 the 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.

Illustrations

Worked examples

Example 1 — a first encounter with Themis (solar power plant)

Start with the simplest possible case. Write down what Themis (solar power plant) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Themis (solar power plant) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Themis (solar power plant) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Themis (solar power plant)

In research: Themis (solar power plant) appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Themis (solar power plant) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Themis (solar power plant) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures in Pyrénées-Orientales, Energy development, Solar power in France, so understanding it makes those chapters shorter.
In everyday life: Look for Themis (solar power plant) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Themis (solar power plant) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Themis (solar power plant) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Themis (solar power plant) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Themis (solar power plant) in simple terms?

Why does Themis (solar power plant) matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Themis (solar power plant)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Themis (solar power plant).