How Electricity is Made: PART THREE- SOLAR POWER

As the planet‘s human population continues to grow and demands on natural resources increase, to continue with current practices is highly unsustainable. We know that relying on coal, oil and natural gas threatens our future with toxic pollution, global climate change. Instead of relying on unsustainable fossil fuels, we must transform our economy and learn to thrive on the planet’s abundant supply of renewable energy.

SOLAR POWER

The sun provides energy in two forms – light and heat. The sun can be used to heat water in our homes and businesses. It can also produce electricity. Energy produced by the sun is called solar power. Since the beginning of mankind we have used the energy of the sun to dry clothes and food, but it wasn’t until 1954 that scientists in the United States worked out a way to use the sun to create electricity. Solar Power is a source of renewable energy that is now a mature technology option.  There are two main types of solar electricity generation, Photovoltaic cells and Solar Thermal energy.

PHOTOVOLTAIC SYSTEM

Solar panels (photovoltaic cells) are a local option for generating renewable energy. Prices have dropped rapidly so solar power is now more accessible. Photovoltaic (PV) cells, which as the name implies (photo meaning “light” and voltaic meaning “electricity”), convert sunlight directly into electricity. Small-scale and most large-scale installations are photovoltaic systems, which

Solar-PanelsThe scientists invented photovoltaic cells (or panels) to capture the energy from the photons that make up light (sun’s energy) and turn it into electricity. Photovoltaic cells are made of special materials called semiconductors such as silicon. Sunlight is used to charge electrons in the silicon. The energised electrons move through the cell and flow into a wire, creating an electric current. The electric energy is then able to be used or stored for later use.

The sun produces a lot of energy in a wide light spectrum, At midday on a cloudless day, the surface of the Earth receives 1,000 watts of solar power per square meter on average. But we have so far learned to capture only small portions of that spectrum and convert them to electricity using photovoltaic. The efficiency of a solar cell is a measure of its ability to convert energy; this is expressed as a per cent. So, today’s commercial solar systems are about 16- 21% efficient. For comparison, a typical fossil fuel generator has an efficiency of about 28%.

There are different types and quality of Photovoltaic cells. PLG solar energy street lights use the highly effective mono- crystal silicon solar cell. Mono- crystalline Solar Panels have the highest efficiency available. These can achieve 21% efficiency

SOLAR THERMAL ENERGY

The second common type of solar electricity is produced by concentrating sunlight, using mirrors, onto a small target containing a liquid; that liquid becomes very hot due to the concentration of light and its conversion to heat, and that heat is then used to boil the liquid in order to drive a turbine.

thermal-energyWhat you might notice here is that that turbine is basically, once again, a heat engine, and so subject to the same theoretical efficiency limits as a coal fired power plant.

The main difference, however, is that with coal we are looking at a non-renewable resource which costs money and causes environmental damage to extract, whereas with solar we are looking at a renewable resource that is basically free once the solar station is set up.

Advantages of using solar energy

•             It’s almost free once the equipment is installed.

•             Energy from the sun is renewable (it won’t run out).

•             It is very useful for remote areas that are not connected to the main electricity grid.

•             It is environmentally safe (i.e. it produces no greenhouse gases).

•             Australia has heaps of sunshine!

Disadvantages of using solar energy

•             It doesn’t work at all at night.

•             Solar generators maybe expensive and require a lot of space.

At the Photovoltaic Lighting Group we have integrated the Latest technology to provide a reliable system that will stand the test of time. We have base solar lighting kits available which include; pole, batteries, solar panel, wiring with connectors, luminaire and controller. The kits are designed for easy installation and maintenance. We welcome all enquiries regarding custom designs and needs.

KONICA MINOLTA DIGITAL CAMERAAuthor Rachel McCann

Project Manager

Photovoltaic Lighting Group www.plgaustralia.com.au

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