Energy from the sun
The sun has produced energy for billions of years and is the ultimate source for all of the energy sources and fuels that we use. People have used the sun's rays (solar radiation) for thousands of years for warmth and to dry meat, fruit, and grains. Over time, people developed technologies to collect solar energy for heat and to convert it into electricity.
Radiant energy from the sun has powered life on earth for many millions of years.
Solar thermal (heat) energy
A solar oven (a box for collecting and absorbing sunlight) is an example of a simple solar energy collection device. In the 1830s, British astronomer John Herschel used a solar oven to cook food during an expedition to Africa. People now use many different technologies for collecting and converting solar radiation into useful heat energy for a variety of purposes.
We use solar thermal energy systems to heat:
- Water for homes, buildings, or swimming pools
- Air inside homes, greenhouses, and other buildings
- Fluids in solar thermal power plants
Solar photovoltaic systems
Solar photovoltaic (PV) devices, or solar cells, convert sunlight directly into electricity. Small PV cells can power calculators, watches, and other small electronic devices. Larger solar cells are grouped in PV panels, and PV panels are connnected in arrays that can produce electricity for an entire house. Some PV power plants have large arrays that cover many acres to produce electricity for thousands of homes.
Benefits and limitations
Using solar energy has two main benefits:
- Solar energy systems do not produce air pollutants or carbon dioxide.
- Solar energy systems on buildings have minimal effects on the environment.
Solar energy also has some limitations:
- The availability and amount of sunlight that arrives at the earth's surface varies depending on time of day, location, season of the year, and weather conditions.
- The amount of sunlight reaching a square foot of the earth's surface is relatively small, so a large surface area is necessary to absorb or collect enough energy to be useful.
Last reviewed: December 27, 2022