physics

Solar Energy Generating Systems

Solar Energy Generating Systems is a physics 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 Solar Energy Generating Systems rather than just read about it. In short: Solar Energy Generating Systems (SEGS) is a concentrated solar power plant in California, United States. With the combined capacity from three separate locations at 354 megawatt (MW), it was for thirty years the world's largest solar thermal energy generating facility, until the commissioning of the even larger Ivanpah facility in 2014.

Key takeaways

Solar Energy Generating Systems belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Solar Energy Generating Systems to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Solar Energy Generating Systems from memory before moving on to harder problems.

Reference excerpt

Solar Energy Generating Systems (SEGS) is a concentrated solar power plant in California, United States. With the combined capacity from three separate locations at 354 megawatt (MW), it was for thirty years the world's largest solar thermal energy generating facility, until the commissioning of the even larger Ivanpah facility in 2014. It was also for thirty years the world's largest solar generating facility of any type of technology, until the commissioning of the photovoltaic Topaz Solar Farm in 2014. It consisted of nine solar power plants in California's Mojave Desert, where insolation is among the best available in the United States. SEGS I–II (44 MW) were located at Daggett (34°51′45″N 116°49′45″W); they have been replaced with a solar photovoltaic farm. SEGS III–VII (150 MW) were installed at Kramer Junction (35°00′43″N 117°33′32″W); all five SEGS have undergone demolition. SEGS VIII–IX (160 MW) are located at Harper Lake (35°01′55″N 117°20′50″W). NextEra Energy Resources operates and partially owns the plants located at Kramer Junction. On January 26, 2018, the SEGS VIII and IX at Harper Lake were sold to renewable energy company Terra-Gen, LLC. A tenth plant (SEGS X, 80 MW) had been in construction and SEGS XI and SEGS XII had been planned by Luz Industries, but the developer filed for bankruptcy in 1992, because it was unable to secure construction financing. The site of SEGS X was later licensed for a solar photovoltaic farm, Lockhart Solar PV II. Most of the thermal facilities were retired by 2021, and photovoltaics were built on the same sites.

Plants' scale and operations Before retirement and replacement of SEGS I-VII with solar photovoltaics, the plants had a 354 MW net (394 MW gross) installed capacity. The nameplate capacity, which operating continuously, would dеliver the samе net power output, coming only from the solar source was around 75 MWe —, representing a 21% capacity factor. In addition, the turbines could be utilized at night by burning natural gas. NextEra claimed in 2009 that the solar plants could power 232,500 homеs (during the day, at peak power) and displace 3,800 tons of pollution pеr year that would have been produced if the electricity had been providеd by fossil fuels, such as oil. The facilities had a total of 936,384 mirrors and cover more than 1,600 acres (647.5 ha). Lined up, the parabolic mirrors would have extended over 229 miles (369 km). As an example of cost, in 2002, one of the 30 MW Kramer Junction sites required $90 million to construct, and its operation and maintenance cost was about $3 million per year (4.6 cents per kilowatt hour).

Principle of operation

The installation uses parabolic trough, solar thermal technology along with natural gas to generate electricity. About 90% of the electricity is produced by the sunlight. Natural gas is only used when the solar power is insufficient to meet the demand from Southern California Edison, the distributor of power in southern California.

Mirrors The sun shines on glass panels, which are 94% reflective, unlike a typical mirror, which is only 70% reflective. The mirrors automatically track the sun throughout the day. The greatest source of mirror breakage is wind, with 3,000 mirrors typically replaced each year. Operators can turn the mirrors to protect them during intense wind storms. An automated washing mechanism is used to periodically clean the parabolic reflective panels. The term "field area" is assessed as the actual collector area.

Heat transfer The sunlight bounces off the mirrors and is directed to a central tube filled with synthetic oil, which heats to over 400 °C (750 °F). The reflected light focused at the central tube is 71 to 80 times more intense than the ordinary sunlight. The synthetic oil transfers its heat to water, which boils and drives the Rankine cycle steam turbine, thereby generating electricity. Synthetic oil is used to carry the heat (instead of water) to keep the pressure within manageable parameters.

Individual locations The SEGS power plants were built by Luz Industries, and commissioned between December 20, 1984 and October 1, 1990. After Luz Industries' bankruptcy in 1991 plants were sold to various investor groups as individual projects, and expansion including three more plants was halted. Kramer Junction employs about 95 people, and 45 people work at Harper Lake.

Harper Lake Until Ivanpah Solar Power Facility was commissioned in 2014, SEGS VIII and SEGS IX, located at 35°01′55″N 117°20′50″W were the largest solar thermal power plants individually and collectively in the world. They were the last, the largest, and the most advanced of the nine plants at SEGS, designed to take advantage of the economies of scale. Construction of the tenth plant in the same locality was halted because of the bankruptcy of Luz Industries. Construction of the approved eleventh and twelfth plants never started. Each of the three planned plants would have had 80 MW of installed capacity. Abengoa Solar recently constructed the 280MW Mojave Solar Project (MSP) adjacent to the SEGS VIII and SEGS IX plants. The MSP also uses concentrating solar thermal trough technology. Starting in February 2020, SEGS VIII no longer burned natural gas. The last production month was October 2021. SEGS IX stopped burning natural gas starting in October 2020, except for January 2021.

Kramer Junction

This location (35°00′48″N 117°33′38″W) receives an average of 340 days of sunshine per year, which makes it an ideal place for solar power generation. The average direct normal radiation (DNR) is 7.44 kWh/m2/day (310 W/m2), one of the best in the nation. This was the location of SEGS II - VII, which were retired in 2019. As of 2021, they were going to be replaced with a new solar photovoltaic array called Resurgence I.

Daggett SEGS I and II were located at 34°51′47″N 116°49′37″W and owned by Cogentrix Energy (Carlyle Group). SEGS II was shut down in 2014 and was replaced by Sunray 3 (EIA plant code 10438), a 13,8 MW photovoltaic system. SEGS I was shut down one year later and replaced by 20 MW PV system Sunray 2 (EIA plant code 10437). Sunray 2 and Sunray 3 started production in 2017 as per EIA data.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Solar Energy Generating Systems

Start with the simplest possible case. Write down what Solar Energy Generating Systems claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, 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 Solar Energy Generating Systems 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 Solar Energy Generating Systems 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 Solar Energy Generating Systems

In research: Solar Energy Generating Systems appears in physics 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 Solar Energy Generating Systems 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: Solar Energy Generating Systems is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures in San Bernardino County, California, Energy infrastructure completed in 1984, Energy infrastructure completed in 1985, so understanding it makes those chapters shorter.
In everyday life: Look for Solar Energy Generating Systems 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 Solar Energy Generating Systems in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Solar Energy Generating Systems 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 Solar Energy Generating Systems out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Solar Energy Generating Systems in simple terms?

Why does Solar Energy Generating Systems matter?

Because it connects several physics 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 Solar Energy Generating Systems?

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 Solar Energy Generating Systems.