As a youngster, they taught me that the solar system was the earth and 8 other planets that revolved around the sun. This is still the case, but when the term “solar” is used when speaking about electricity and power, it takes on a whole different meaning. With clean, self-reliant electricity generation and sustainable energy sources, it seems that “solar” is the term discussed the most. But this is not an easy term to wrap your head around immediately, so let’s have a look at what “solar” and “solar power” really means, not only in the photovoltaic industry but all facets of the word.
A definition of solar
Solar energy is radiant light and heat from the sun harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture and artificial photosynthesis. It is an important source of renewable energy and its technologies are broadly characterised as either passive solar or active solar, depending on the way they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power and solar water heating to harness the energy. Passive solar techniques include orienting a building to the sun, selecting materials with favourable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
How does electricity come from the sun?
Solar power is a renewable source of electricity and heat that is derived from the sun. The sun’s energy creates heat and light, but it can also be converted into making electricity. And lots of it.
In a single hour, the amount of power from the sun that strikes the Earth is more than the entire world consumes in a year – Rebecca Harrington, Tech Insider
The sun emits energy in the form of solar radiation and technology like solar cells (also called photovoltaic or PV cells) convert the sun’s light into usable energy. Solar cells are made of semiconductive materials, similar to those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity. Sunlight is made up of tiny packets of energy called photons. These photons radiate out from the sun, and about 150 million kilometres later, they collide with a semi-conductor on a solar panel here on earth.
Source: Cosmos Magazine
PV panels have been around for years now, but recent advancements have greatly improved their efficiency and electrical output. This all happens at the speed of light. Solar panels are made up of several individual cells, each with a positive and a negative layer which create an electric field. It works similar to a battery. The photons strike the cell and their energy frees some electrons from the semiconductor material. The electrons create an electric current which is harnessed by the wires connected to the positive and negative sides of the cell.
The electricity created is multiplied by the number of cells in each panel, and the number of panels in each solar array. Combined, a solar array can make a lot of electricity for your home or business. Photovoltaic power stations and solar-thermal power plants exist on a much larger scale. When built at a “utility-scale”, both systems can provide large amounts of power to the electricity grid.
Source: Energy Sage
Solar-thermal power plants use mirrors instead of solar cells to turn the sun’s energy into a concentrated heat source. The heat is used to boil water and to drive a steam turbine that generates electricity in large quantities. Whether powering individual homes and buildings or solar thermal power plants, solar energy is an inexhaustible, virtually pollution-free fuel source.
The large magnitude of solar energy available makes it a highly appealing source of electricity.
The United Nations Development Programme in its 2000 World Energy Assessment found that the annual potential of solar energy was 1,575 to 49,837 exajoules (EJ). This is several times larger than the total world energy consumption, which was 559,8 EJ in 2012.
In 2011 the International Energy Agency said that “the development of affordable, inexhaustible and clean solar energy technologies will have huge long-term benefits. It will increase countries’ energy through reliance on an indigenous, inexhaustible–and most important–independent resource, enhance sustainability, reduce pollution, lower the cost of mitigating global warming, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared.”