Current Technologies to Harness Solar Energy

There are many technologies that use solar energy to produce electricity or heat in one or the other way. I would like devote this post to describe various photovoltaic solar panels and concentrated solar power.

 

Photovoltaic Cell

The most famous one is photovoltaic (PV) cell that converts solar radiation into electricity. This is the technology that is most commonly installed on residential houses. Many PV cells of the same size are arranged into a module. Once a module is attached to some sort of a frame, it becomes a solar panel. Arrangement of solar panels is called an array:

 

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How do PV cells work?

All PV cells' work is based on the same principle, described in the former post How electricity works.

Types of PV Cells

There are three types of PV cells:

1. Monocrystalline solar cell is cut from a single crystal of silicon. 
2. Polycrystalline solar cell is cut from a block of silicon that consists of many interlocked crystals of silicon.
3. Thin film PV cells are made by layering several thin films made of photovoltaic materials. That material can be made of amorphous silicon, cadmium telluride, copper indium gallium selenide, dye-sensitized solar cell, and other organic solar cells. (source)

Which type of a PV cell is better? In order to answer this question, one needs to look at cells' prices and efficiencies. Here is a comparison:

	Monocrystalline	Polycrystalline	Thin film PV cell
Cell	Image source	Image source
Panel	Image source	Image source	Image source
Efficiency	Up to 15 % - high	10-10.5 % - medium	8 % - low
Cost	High	High	Low
Made off	Mono-crystalline silicon	Poly-crystalline silicon	Amorphous silicon, cadmium telluride, copper indium gallium selenide, dye-sensitized solar cell

What are Current Uses of PV Solar Panels?

There is a great variety of products on the market that use PV solar cells. Take a look at some of them:
1) Solar farm made from rows and rows of solar panels that create electricity:

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2) The most common use of PV solar panels is installing them on the roofs of the buildings to provide them with electricity and heat:

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This diagram shows how solar energy is converted into electricity that can be used at home. Click on the image to enlarge it. Image source

3) There is a variety of solar chargers for batteries, cell phones, laptops, etc (this is my DIY solar cell phone charger for Nokia E71 and how I made it)

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iPhone solar cell phone charger. Image source

Laptop solar cell phone charger. Image source

4) Solar buses - yep, those already exist!

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 5) Solar roads are coming!

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Can I Make My Own Solar Panels?

Yes you can. There is a lot of stuff to be found on YouTube and generally in the Internet. I found this source to be very informative about solar energy, panels, and building own solar panels.

Concentrated Solar Power (CSP) 

Concentrated solar power (CSP) technologies have a similar working process. Mirrors concentrated solar energy on one spot, and that energy is used either to directly create electricity, or as heat that warms up water to the point when it steams and generates electricity just like any other nuclear/coal/natural gas plant does it.

The main difference between these technologies lies in the arrangement of components. Let's have a look at known CSP technologies.

Concentration of sunlight using (a) parabolic trough collector (b) linear Fresnel collector (c) central receiver system with dish collector and (d) central receiver system with distributed reflectors. Image source

Parabolic Through System

Linear Fresnel Reflector System

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Dish Collecting System or Dish/Engine System for CSP

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Central Receiver System with Distributed Reflectors

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