via alphr : Life on Earth could not survive without the sun. It provides light and heat, the seasons and the day and night cycle necessary for life to have evolved. Today, we’re exploiting the energy from the sun to power our lives and experts say one day, this source of energy may be all we need. But, behind the headlines what exactly is solar power and how do we harness it?
What is solar power?
There are two main types of solar energy: photovoltaics and concentrated solar power (CSP), also known as concentrated solar thermal.
Solar energy accounts for around 1% of global electricity generation, but it is predicted to play a much greater role in the future. It is a renewable energy source, which produces no greenhouse gases or toxic waste, and it relies on light from the sun, which reaches all corners of Earth. It generates electricity using photovoltaic solar cells, typically fitted into solar panels, which convert sunlight into energy on an atomic level.
Solar panels: how do they work?
Solar cells make use of a property called the photovoltaic effect, which describes the process of a photon, or a particle of light with the right wavelength, hitting the cell and causing an electron to flow. This effect was first noticed in 1839 by Henri Becquerel, a French physicist and Nobel laureate.
Most photovoltaic cells are made of a thin film of semiconductors, which creates an electric field. In the most basic terms, when an electron is excited by the light striking the cell, it will flow from one side of the semiconductor to the other, creating a current.
One of the benefits of using solar cells is their size does not matter when it comes to efficiency. For example, a 10 square metre array of PV cells is just as efficient as a 10 square kilometre array – which is why the development of off-grid solar cells for people’s homes and businesses is taking off. This is unlike any other renewable energy. By comparison, if you built a wind turbine in your back garden it would be ten times smaller than one in a wind farm and nowhere near as efficient.