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We are living on the brink of a green energy revolution. Climate change constantly reminds us of humans of just how dirty, irresponsible, and careless we’ve been.
With every storm, drought, and flood, we are shocked into realizing that pumping the atmosphere full of garbage was kind of a stupid thing to forget about. With that in mind, the world is turning its lonely eyes toward renewable energy.
Perhaps the most well known and trusted form OF RENEWABLE ENERGY is that of solar energy.
It should come as no surprise that the solution to our climate woes would be the sun.
Along with air, water, and sunlight, heat is one of the essential ingredients to all life on earth. It is a resource so fundamental that for thousands of years various human civilizations have personified and worshipped its existence.
The Never-Ending Endeavour
The Aztecs ripped out hearts for the sake of the sun god, the Japanese Shinto religion claimed their people were decedents of the sun, and the Egyptian sun god Ra, ruled all parts of the created world.
By the late 18th century, we began to understand the actual process of photosynthesis by which plants used sunlight to produce the energy necessary to survive.
Thus, in 2019, it is no wonder that we should finally look back and realize there might be something to this whole sun thing.
More then any other green energy source, the sun is the most widely available and clean. With the introduction of worldwide LED lighting, solar can now produce enough light and heat to meet the world’ energy needs every 50 minutes.
In theory, it has been proposed, that a 100 by 100 mile square of solar panels in the desert of Utah or Nevada could power the whole of the United States.
The Three Main Different Types of Solar Energy
There are two basic types of solar energy that we can employ to harness the sun’s potential.
Photovoltaic technology is used to capture sunlight and convert it into electricity. Solar thermal technology focuses on capturing the sun’s heat. These two types can be used to power a basic home or be employed on an industrial scale that can power an entire grid.
The potential of photovoltaic solar energy was first discovered in France in 1839. In short, in order to create an electric current, an atom’s electrons need to be rapidly displaced. Photons, or particles of light, have the ability to excite and displace the electrons of certain semiconductors.
By far the most common semiconductor in use for this purpose is silicon. When sunlight hits the cell of a modern photovoltaic solar panel, the energy created by photons interacting with electrons is converted into electricity.
This is electricity is initially formed as direct current which is then converted to alternating current by an inverter so it can be utilized. It’s how most solar panels work and the most common type to the average homeowner.
Photovoltaic panels are used on small scales, from miniature devices such as solar flood lights and solar path lights to powering entire ‘green homes’, or large scales such as in the case of the Noor Complex Solar Plant in Morroco.
Solar Thermal Power
Solar thermal power is probably the most widespread form of solar power in use today. Solar thermal collectors absorb heat from the sun, transfer it via air, water, or an antifreeze solution which then moves it to the areas that need to be heated.
Low-temperature solar thermal power works with temperatures below 100 degrees Celsius and are utilized for commercial use such as water heating.
The most common types of thermal capture devices are flat-plate collectors.
Theses plates are covered with a dark material that best captures the sun’s heat. Below this is a special type of insulation that is covered with glass in order to create a greenhouse effect to most efficiently generate heat. Small tubes of transfer fluid are then heated.
As the heat builds within the collector, the fluids flow beneath and transfer the heat to a storage tank. This in turn provides heat for buildings, swimming pools and the like.
This form of solar power is taken to an even more potent level with concentrated solar power. Solar power plants are used on an industrial scale and serve to replace fossil fuels while using the same basic technology and principles of a traditional power plant.
Here’s a video that explains the process:
This steam, in turn, spins a massive turbine that activates a generator to produce electricity. While extremely effective and decidedly simple, the use of greenhouse gases to boil water has made this model obsolete for the environment and our health.
That said, the goal is to simply to heat water to the point of steam conversion. Luckily for us, the sun is really good at that.
There are different ways to use the sun to boil water on a massive scale. Parabolic-trough systems use long rectangular, curved mirrors to focus sunlight onto pipes containing oil. This superheated oil is then directed to boil water and generate steam to spin the turbine.
A dish or engine system uses a large mirrored dish to collect and concentrate the heat of the sun’s rays onto a receiver.
The receiver then transfers this heat to a fluid inside an engine. As the electrons of the fluid become excited by the heat, the fluid expands.
This expansion presses against a piston or turbine and the resulting movement is used to run a generator.
This results in a steady flow of electricity.
Thermal Power Tower System
Lastly, a power tower system uses a field of specially positioned mirrors to focus sunlight on the top of a tower which contains a receiver full of molten salt.
The heat absorbed by the salt is then used to power a generator and thus create electricity. Furthermore, power tower systems have the added benefit of being able to produce electricity after sunset and on cloudy days because molten salt is extremely effective at retaining heat.
In the midst of a climate crisis caused by our thoughtless consumption of fossil fuels, the need to spread knowledge and use of solar power is greater than ever.
They are cleaner, more efficient ways to boil water and excite electrons.
After decades of doing things the wrong way, it’s about time we start doing what plants figured out 470 million years ago.