Solar technologies have evolved a lot since they first made their debut in the 1960s. While previously solar photo voltaic (PV) were seen as a thing of the future, today, technological breakthroughs have positioned the industry for huge growth.
The Earth receives an incredible supply of solar energy. The sun, an average star, is a fusion reactor that has been burning over 4 billion years. It provides enough energy in one minute to supply the world’s energy needs for one year. In one day, it provides more energy than our current population would consume in 27 years. In fact, “The amount of solar radiation striking the earth over a three-day period is equivalent to the energy stored in all fossil energy sources.”
The ability to use solar power for heat was the first discovery. A Swiss scientist, Horace de Saussure, built the first thermal solar collector in 1767, which was later used to heat water and cook food. The first commercial patent for a solar water heater went to Clarence Kemp of the US in 1891.
Producing electricity from solar energy was the second discovery. In 1839 a French physicist named Edmund Becquerel realized that the sun’s energy could produce a “photovoltaic effect” (photo = light, voltaic = electrical potential). In the 1880s, selenium photovoltaic (PV) cells were developed that could convert light into electricity.
People can harness the sun’s energy in a few different ways:
- Photo voltaic cells, which convert sunlight into electricity.
- Solar thermal technology, where heat from the sun is used to make hot water or steam.
- Passive solar heating, which can be as simple as letting the sun shine through windows to heat the inside of a building.
Do you have a solar calculator or watch? These items are powered by photovoltaic cells. A photovoltaic cell absorbs light and converts it directly into electricity. A group of photovoltaic cells is known as a solar panel.
You may have seen solar panels on houses, on electronic road signs, or in parking lots to power lights. People who have solar panels on their homes buy less electricity from their utility companies because they’re producing some electricity on their own. If you have enough solar panels, you might even be able to generate more power than you need. In some states, this means you can run your electric meter backwards and give your extra electricity to the rest of the community. The electric company ends up paying you!
Solar Thermal Technology
Another way to tap solar energy is by collecting the sun’s heat. Solar thermal power plants use heat from the sun to create steam, which can then be used to make electricity. On a smaller scale, solar panels that harness thermal energy can be used for heating water in homes, other buildings, and swimming pools.
Passive Solar Heating
Have you ever noticed how sunlight streaming through a window can make your home feel warmer, even on a cold day? If so, you’ve seen passive solar heating in action! People can design or remodel buildings to take advantage of heat from the sun during the winter. It helps to have large windows that face south (the side that gets the most sunlight everywhere north of the Equator) and are not shaded by other buildings or trees. A good design often includes overhangs, movable awnings, or blinds that block the sun during the summer when people need to cool their homes instead of heating them.