Despite the UK’s reputation for bad weather, the humble solar cell still has great potential over here.
In addition to the fact that they work in cloudy and overcast conditions, new breakthroughs have made PV cells safer and cheaper than ever, the perfect addition for British homeowners.
It might help to know exactly where these devices came from and how they work though, so you can better understand their place in our society.
A History of Solar Power
While most people think of solar as a recent phenomenon, work and interest in this area actually goes back over a hundred years. Some important dates that led up to the invention of the first solar cell include:
• In 1767, the first solar collector, in fact a solar oven, was created by Horace-Benedict de Saussure.
• In 1865, Auguste Mouchout produced a prototype solar motor and created the world’s first solar powered steam engine.
• In 1873, Willoughby Smith discovered that selenium could conduct and convert solar energy. Initial prototypes weren’t successful.
• In 1891, the inventor, Clarence Kemp, invented the world’s first solar heater.
• In 1893, Charles Fritts created the world’s first solar cell by coating sheets of selenium with thin layers of gold.
From these beginnings, solar energy then continued to develop over the years. In fact, almost all present solar conversion methods were invented before WW1. Once war arrived though, the need for cheaper, more efficient technology drove up the demand for fossil fuels and pushed solar power to the sidelines for the next 50 years.
We now sit at a resurgence of solar technology, with renewed interest in this technology all over the globe. Solar cells are becoming more efficient while being cheaper and safer to produce. Unfortunately, the influence of the fossil fuel industry still puts these renewable energy devices at risk of fading into obscurity for a second time. The world must come together to stop this from happening, especially with global warming as a reality.
How the Photovoltaic Cell Works
A PV cell has one job: converting sunlight into electricity. The key component that allows it to do this is the semiconductor sheet found within. This can be made from silicone although newer solar panels now use better thin film technology which is created from crystal blends such as copper-indium-gallium-selenide. When the sunlight hits a PV cell, several things happen:
1. The photons in the light hit the semiconductor atoms
2. An electron absorbs the energy and is knocked up into a higher energy level
3. This electron is driven by an electric field that runs through the cell and is turned into an electric current
The field is created by the properties of the semiconductor that makes up the cell. Let us say we’re using silicone. By adding certain materials, we can create two types, one positively and one negatively charged. This is because one contains excess electrons and the other lacks in electrons.
By forming two plates of different silicone types, we have positive and negative poles which then create an electric field in-between. When the electron is knocked off by a photon, it can then move through a cell in an orderly manner thanks to this field. Because each electron is moving in the same way, this forms a current which can then be used to power all manner of devices.
Some mention should also be made of the power efficiency of solar cells. Simply put, power efficiency is the percentage of light that is converted into electricity. Although PV cells in satellites convert 50% of the photons that hit them into usable electricity, these are very expensive to make. At a lower price tag, present-day, domestic cells usually feature a power efficiency of around 17%. Hopefully, we’ll see solar systems becoming cheaper to produce with new technological advances which will then simultaneously make them more efficient as well.
Hopefully this has been an informative look at where the typical solar cell has come from and what it can do for us today. These are crucial devices when it comes to beating climate change and stopping global warming and it is important that we know as much about them as possible so we can make a better world.
By Olivia Breen