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Photovoltaic cells

What is a photovoltaic cell and how does it fit in with solar energy?

solar cells

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What are 'photovoltaics'?

Photovoltaics is the technology for building solar cells and making solar energy. In fact, a photovoltaic cell (PV cell) and a solar cell are the same thing; the only difference is that solar cells get their name when they start capturing energy from the sun.

The word photovoltaic comes from the Greek meaning light (photo) and electric (voltaic) and that's exactly what PV cells do - convert light into electricity.

PV cells create electricity by absorbing sunlight and using that energy to generate an electric current.

Why photovolatics?

PV electricity is becoming more important because of dwindling oil supplies and concerns over carbon emissions from fossil fuels. PV cells are a solution because they provide a sustainable alternative using something the Earth has in abundance - sunshine.

The production of PV cells has been doubling about every two years. This means that PV cells are the world's fastest growing energy technology.

If the technology is out there, why aren't I using it?

Good question, but the answer is simple - it's too expensive. While many people and companies use solar energy, it is too expensive to be mainstream. High prices make it unlikely the majority of people will switch to solar until the cost becomes the same as its cheaper, dirtier competitors.

There are also technical problems like PV cells not working at night: no sun, no electricity. However, scientists are working on this conundrum too.

Is it going to become cheaper?

This is what the majority of PV research is about. We know the technology works but we need to get more bang for the buck. That is to say, we need ways to get more electricity for every dollar spent.

Scientists are trying to do this in two ways:

First, reduce the cost of building the cells. PV cells are made out of expensive materials like silicon, so the less silicon used the cheaper the cell. As more and more cells are built, manufacturers are learning better, cheaper ways to construct them.

The original PV cells that were built on silicon 'wafers' are called first generation PV cells. Newer, cheaper second generation cells are built from thin silicon 'films'.

Second, make PV cells produce more electricity. New technology is constantly being researched for cells to convert more energy from sunlight into electricity. PV cells that use newer, more effective technology are called third generation PV cells. The hope is to improve the efficiency of cells from about 20 per cent (for first and second generation) to around 60 per cent.

The final way that PV technology becomes cheaper is through government subsidies. Governments support PV research because it creates high tech jobs in a very fast growing industry that makes clean, sustainable energy.

When will these technologies make PV electricity competitive?

Over the next 20 years PV technology is going to get much cheaper. First generation cells will have lower production costs. Cheaper second generation cells will become more available and third generation technology will mean that all the cells will be more effective.