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Solar power

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Solar power is the process of converting energy from sunlight into electricity. This technology is a vital part of the global energy transition. It helps provide low-carbon power to limit climate change and improve energy security.

solar share energy, World, 2024 (cropped)
solar share energy, World, 2024 (cropped)

Scientists and engineers use different methods to capture this energy. The two primary technologies are photovoltaics (PV) and concentrated solar power (CSP). While PV converts light directly into electricity, CSP uses heat to drive mechanical processes. Both methods play a role in how we power our modern world.

Photovoltaic systems work through a process called the photovoltaic effect. This effect allows solar cells to convert light directly into an electric current.

PV-system-schematics-residential-Eng
PV-system-schematics-residential-Eng

Most modern solar cells are made of crystalline silicon, which makes up over 90% of the market. In a PV system, multiple solar cells are connected inside panels. These panels are then wired together into larger arrays. The arrays produce direct current (DC) power, which fluctuates based on sunlight intensity. To make this power useful for homes, an inverter converts the DC power into alternating current (AC).

Parabolic trough
Parabolic trough

Some systems are grid-connected, while others use batteries for energy storage to work at night.

Concentrated solar power, or CSP, uses a different mechanical approach. Instead of using light to move electrons directly, CSP uses sunlight to create intense heat.

IvanpahRunning
IvanpahRunning

These systems use lenses or mirrors combined with solar tracking systems. The mirrors focus a large area of sunlight onto a single hot spot. This extreme heat is used to create steam. The steam then drives a conventional steam turbine to generate electricity. While CSP can efficiently use thermal storage to provide power, it is less common than PV. In 2022, less than 1% of solar power came from CSP because its cost is over twice that of PV.

There are many different ways to install these technologies in the real world. Utility-scale solar refers to large solar farms built on the ground to provide massive amounts of power. Many people also use rooftop solar, which was mounted on nearly half of all solar power installed in 2022.

Solar farm in Wisconsin 01
Solar farm in Wisconsin 01

New configurations are also emerging, such as floating solar farms and solar canopies over parking lots. One interesting method is vertical agrivoltaics. In this system, solar cells are oriented vertically on farmland. This allows the land to grow crops and generate renewable energy at the same time.

The history of solar technology began in the 1860s with researchers like Augustin Mouchot. In 1884, Charles Fritts installed the first rooftop photovoltaic array in New York City. These early selenium cells were only 1% efficient. Later, in 1931, Bruno Lange developed a photo cell using silver selenide. A major breakthrough occurred in 1954 when researchers Gerald Pearson, Calvin Fuller, and Daryl Chapin created the silicon solar cell.

These early silicon cells had efficiencies between 4.5% and 6% and were very expensive. In 1957, Mohamed M. Atalla developed silicon surface passivation, a process that remains critical for efficiency today.

Solar power has seen massive growth in recent decades. In 2024, solar power generated 7% of global electricity.

2024-2025 Change in electricity sources and demand
2024-2025 Change in electricity sources and demand

This is more than 5,151 terawatt-hours (TWh) out of a total of 186,383 TWh of primary energy. The capacity of grid-connected solar PV systems has doubled roughly every three years as costs have fallen. Between 2010 and 2020, the cost of utility-scale solar PV fell by 85%. China is currently a global leader, holding about half of the world's solar power. In 2022, the global solar generation capacity exceeded 1 terawatt (TW) for the first time.

Geography plays a significant role in how much solar energy a place can collect. Areas closer to the equator generally receive more sunshine.

However, solar tracking systems can help increase energy potential in areas farther from the equator. Other factors like daytime cloud cover and land availability also affect how much power can be made. Solar is now one of the cheapest sources of new electricity in most countries. It is often compared to onshore wind power for its low cost. As the world moves toward electrification, solar power will continue to be a key part of the global energy system.

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🖼️ Images & Media (15)
File:PV-system-schematics-residential-Eng.png
PV-system-schematics-residential-Eng.png
File:Parabolic trough.svg
Parabolic trough.svg
File:Share of electricity production (from solar).png
Share of electricity production (from solar).png
File:per capita solar, World, 2024 (cropped).svg
per capita solar, World, 2024 (cropped).svg
File:solar share energy, World, 2024 (cropped).svg
solar share energy, World, 2024 (cropped).svg
File:2024-2025 Change in electricity sources and demand.svg
2024-2025 Change in electricity sources...
File:World PVOUT Solar-resource-map GlobalSolarAtlas World-Bank-Esmap-Solargis.png
World PVOUT Solar-resource-map...
File:Reality versus IEA predictions - annual photovoltaic additions 2002-2016.png
Reality versus IEA predictions - annual...
File:IvanpahRunning.JPG
IvanpahRunning.JPG
File:Solar Plant kl.jpg
Solar Plant kl.jpg
File:Solar farm in Wisconsin 01.jpg
Solar farm in Wisconsin 01.jpg
File:Seasonal cycle of capacity factors for wind and photovoltaics in Europe under idealized assumptions.png
Seasonal cycle of capacity factors for...

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