How Solar Panels Work

how solar works
By Greg Whitburn

Solar panels work through the "Photo-voltaic Process" - where radiation energy (photo) is absorbed and generates electricity (voltaic). Let's explore it below.

How solar panels work diagram
A cell level view of how solar panels work. This is called a photovoltaic process.

Radiation energy is absorbed by semi conductor cells - normally silicon – and transformed from photo energy (light) into voltaic (electrical current).

When the sun's radiation hits a silicon atom, a photon of light energy is absorbed, 'knocking off' an electron.

These released electrons create an electric current.

The electric current then goes to an inverter, which converts the current from DC (direct current) to AC (alternating current).

The system is then connected to the mains power or electricity grid.

Crystalline Silicon Solar Panels

Traditional systems, called crystalline silicon solar modules, involve wafers of refined silicon beneath sheets of glass. The panels are surrounded by a metal frame.

These are by far the most common solar panels. If you've come across a solar panel installation, chances are it uses crystalline silicon technology.

Crystalline silicon technology has been used for around 50 years, and was first developed for powering satellites in space.

Current off the shelf crystalline silicon systems are generally capable of converting up to about 18 % of solar radiation exposure into useable electricity. This is termed as a photovoltaic efficiency of 18%.

The main complaint of crystalline silicon is that the systems are expensive and bulky, installation requires a lot of wiring and labour, and that glass can be prone to damage.

how solar panels work - installation
A solar technician installs solar panels

Thin film solar panels

The new breed of solar technology is thin-film solar panels. Thin film is less bulky than crystalline silicon, and increasingly cheaper to produce.

Thin-film solar energy systems currently have a lower photovoltaic efficiency than crystalline silicon – converting around 8% of radiation exposure – however the conductibility is expected to sharply rise as current research improves the method.

Thin-film solar panels work in the same photovoltaic manner as crystalline silicon modules, without the bulky wafers and glass panelling.

Amorphous silicon is a material used in some thin-film flexible solar panels, which can be moulded to essentially any surface such as roofs or walls.

Rethinking How Solar Panels Work - New Methods and Applications

Solar research and development has boomed around the world over the last few years. These include new photovoltaic conversion methods and application technology, large scale solar farms, and increasingly efficient technology.

thin film solar clading
New tech: Thin film solar panel cladding at the Solar Decathlon in Washington.

Below are a few of these developments.

Stirling Energy Systems’ California plant has developed a new solar electricity production method.

They use the sun's radiation to heat hydrogen gas, which spins a generator, producing electricity. This method has a reported expected efficiency of 30%.

Another development is the number of large scale solar farms, which has recently spiked.

There are now 56 large scale (20 megawatt or more capacity) solar farms, with at least 27 more in the planning or development stages.

One of the largest, the Montalto di Castro Solar Park in Italy, produces 40,000 megawatt hours per year, enough electricity to power around 13,000 Italian households.

American company Solar Roadways has recently been awarded a grant by the US Federal Highway Administration to develop a solar car park.

The idea is to cover the car park’s surface in solar panels, creating a vast surface area for clean electricity production.

Solar Roadways co-founder Scott Brusaw envisages the project spreading to roads once the technology and methodology has been developed with the carpark project.

Beyond the possibility of turning whole roads into electric grids, other features in the pipeline include built in de-icing mechanisms and LED lighting for driver visibility, as well as recharging stations for electric cars - all using free solar energy.

Another US company, Dow Chemicals, have developed thin-film solar roof tiles.

The solar roof tiles are physically like any other roof tile, and are nailed to the roof just like traditional tiles.

How the tile solar panels work is along the same concept as conventional solar - the tiles plug into each other to create an array, then an electrician connects the panels to an inverter, and into the mains power of the building.

First published January 9, 2012
Last updated February 16, 2021

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48 comments on “How Solar Panels Work”

  1. the information is really helpful one.. With the advancement of technology the use of solar power has to be done...

    This accounts to large amount of renewable energy available

    1. Well it's going to affect them whehetr they can afford it or not. People need to re-think their lives to deal with high energy costs, regardless of your thoughts on global warming. High energy prices are here to stay, especially liquid transportation fuels.Living within walking distance of work is more economical than commuting for many people (not all). Buying solar panels may not be affordable, but reducing consumption certainly is. Not many people consider how attractive vegetarianism is from an economic perspective.Not driving, reducing consumption, and not eating/eating less meat will have more effect than the rich people buying electric cars and solar panels.

  2. This is really insightful. I'm a young entrepreneur working on an idea for solar energy in my home country and would like to get in touch with you for some information. Please contact me on my email address.

    Thank you.

  3. I thought this site was extremely informative and helpful. I like the idea of green energy and it involving solar energy. I too think that solar energy indefinitely has a very bright future. I would like to talk to you more about this. Please send me an e-mail.

  4. Very good and simple explanation for the laymen. I heard that there are organic solar Cells and inorganic cells. what is their efficiency? by the way How exactly the Efficiency is defined and estimated?

    1. Hi KK, thanks! I'm not too sure about that one. I have read a little about naturally formed silicon crystals vs synthasized crystals, but will have to do a little research... watch this space.

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