Photovoltaic (PV) energy: what is it and how does it work?

Photovoltaic energy involves the conversion of sunlight into electricity through the use of photovoltaic cells. These cells, typically made of semiconductor materials such as silicon, absorb photons from sunlight, which in turn generate electric current through the photovoltaic effect.

A photovoltaic (PV) cell, commonly referred to as a solar cell, is a non-mechanical device that converts sunlight directly into electricity. Some photovoltaic cells can convert artificial light into electricity.

Sunlight consists of photons or particles of solar energy. These photons contain different amounts of energy that correspond to different wavelengths of the solar spectrum. When photons hit a photovoltaic cell, they can reflect off it, pass through the cell or be absorbed by the semiconductor material. Only absorbed photons provide energy to generate electricity. When the semiconductor material absorbs enough sunlight, electrons are displaced from the atoms of the material. Special surface treatment of the material during fabrication makes the front surface of the cell more receptive to displaced or free electrons so that they naturally migrate to the cell surface.

The electricity flow in a solar cell

The movement of electrons, each carrying a negative charge, toward the front surface of a solar photovoltaic cell creates an imbalance of electrical charge between the front and back surfaces of the cell. This imbalance in turn creates a voltage potential as the negative and positive terminals of the battery. The cell’s electrical conductors absorb electrons. When wires are connected in an electrical circuit to an external load, such as a battery, electricity flows through the circuit.

Innovation and progress

Recent innovations in photovoltaic technology have increased its efficiency and affordability. Thin-film solar cells, for example, offer flexibility and lower manufacturing costs, expanding the applicability of photovoltaic systems. In addition, advances in nanotechnology have led to the development of more efficient solar panels with improved light absorption capabilities.

Examples of photovoltaic applications

Photovoltaic energy finds applications in various sectors. From solar panels on residential rooftops to large-scale solar farms, photovoltaic systems address both individual energy needs and grid electricity generation.

 

Successful photovoltaic (PV) projects

Solar Energy Generating Systems (SEGS) – California, USA:

SEGS, developed by Luz Industries in the 1980s, includes nine solar power plants in California’s Mojave Desert. These installations use parabolic technology to generate electricity from sunlight. With a total capacity of over 350 megawatts (MW), SEGS is one of the largest solar thermal projects in the world, providing clean energy to thousands of homes.

Mohammed bin Rashid Al Maktoum Solar Park – Dubai, UAE:

The Mohammed bin Rashid Al Maktoum Solar Park is a leading renewable energy project in the United Arab Emirates. It includes a combination of photovoltaic (PV) and concentrated solar power (CSP) technologies, with a total planned capacity of 5,000 MW by 2030. Phase III of the project, operational from 2020, includes the world’s tallest solar tower, rising 260 metres , and has a capacity of 700 MW.

Noor Abu Dhabi – Abu Dhabi, UAE is called the largest photovoltaic power plant in the world, opened in 2019, and is located in the desert in the northeast of the Emirate of Abu Dhabi in the United Arab Emirates (UAE)

The facility is located in the city of Suwayhan, which was chosen for its strategic location. An analysis of the UAE’s heat map reveals that Suwayhan is located in an area with high levels of solar radiation, making it highly suitable for PV investment. The plant has a capacity of 1,177 MW and consists of over 3.2 million solar panels.

 

The advantages of photovoltaic energy are manifold. It is a clean and renewable energy source that contributes to reducing carbon emissions and mitigating climate change. In addition, photovoltaic systems offer decentralised power generation, promoting energy independence and sustainability. In addition, the scalability of PV technology makes it adaptable to a variety of environments, from remote off-grid locations to urban settings.

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D. Strumenlieva
Director, Coca Cola HBC Bulgaria