Exploring different types of solar technologies

Solar energy holds the best promise to solve the world's energy problems. The source of solar power, which is the sun, is abundant. It also the cleanest form of energy with zero carbon footprint.

As such, there have been lots of developments and progress in solar technologies. Here, I will discuss the different types of solar energy technologies, its cost, and its advantages/disadvantages

  • Crystalline Silicon Solar Technology
  • Thin Film Solar Technology
  • Concentrated PV Solar Technology

Silicon Solar Technology

Silicon Solar technology is the 1st generation Photovoltaics technology. The solar cell is made out of silicon wafer, the same material that is used to make semiconductor chips. This is currently the most popular and the most reliable technology. It has nearly 90% of the market share and has over 30 years of experience. Efficiency is about 14-20%.

Thin-film PV System

Thin-film solar technology is relatively new. This technology is quite exciting and promising. It makes use of thin film semiconductor material (Amorphous Si, CDTe, CIS, CIGS) to make solar power. It has around 6% of market share, but continues to grow in popularity. The advantages of thin film technology is that it is low cost and light weight. On the flip side, the efficiency is lower than silicon solar technology. Efficiency is about 8-14%.

The key will be to drive the cost of solar down to $1 per watt point, which is the current price of conventional energy sources. Current solar technology puts the price of solar power at about $3-$4 per watt. With thin film technolgoy, we could see cost of solar coming down to less than $1/Watt within the next few years.

Thin film, based on CIGS (copper indium gallium selenide), can be produced at a cheap cost because it leverages the printing technology that have been around for a long time, thus eliminating many of the high energy, chemical intensive processes that are common in silicon PV manufacturing process. It is very flexible and can be mounted on tops, sides of buildings, windows, cell phones, notebook computers, cars, etc. Nanosolar and First Solar are among the pioneers of thin-film solar developments.

Concentrated PV technology

Concentrating solar power makes up a small portion of the solar industry, but it is a promising technology and is gaining momentum. CSP systems use lenses or mirrors and tracking systems to focus sunlight into a PV surface area for the purpose of electrical power generation. The primary advantages of CPV systems are high efficiency, low system cost, require less amount of solar cell material than conventional PV technology.

Concentrated light allows solar cells to operate more efficiently. Unlike conventional solar cells, which use only one type of semiconductor (silicon), the multijunction cells use 3 three types of semiconductor for each layer. The advantage of using the multijunction cells is that using three materials allow it to efficiently convert light from different parts of the spectrum. As a result, more solar light is being converted to electricity and less goes to heat.

Having an efficient and reliable tracking system is the key to making this technology a success. The optics, lens and the multijunction cells are also as important.

Currently, the cost of building a CSP station is about $2.5 to $4 per watt. With continual improvement and development, this cost is expected to come down.

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