Solar Power Technology – It’s All About the Solar Cell
Solar cells are roughly one-third the cost of implementing a system today which is dramatically less expensive than it was just two years ago. You can argue that the other two-thirds of the system (inverters, rack, & installation) are more important due to their cost, but without the solar cell, nothing else matters.
Solar Photovoltaic Technology – The focus is primarily on solar cell technology due to the leverage and impact that the solar cell has on the entire system. However, we cannot ignore somewhat significant losses in system efficiency due to module assembly and power inverters. In a separate section, we will address the system costs which are affected by solar cell efficiency to a lesser extent than module efficiency, system design and installation, and power inverter (single versus micro-inverter).
The goal is to make a simple, single solar cell technology recommendation for residential use. Technology will evolve, but there is only one preferred solution at any given time.
Monocrystalline solar cells and PV panels are the preferred residential system due to:
- Efficiency (15%+)
|Crystalline Silicon||Monocrystalline||u c-Si||27.6||Better efficiency than polycrystalline makes it the "best" choice due to a significant reduction in the cost of silicon. Uniform blue coloring.|
|Crystalline Silicon||Polycrystalline||p c-Si||20.4||Most common type of cell with good efficiency and cost. Non-uniform blue color.|
|Thin-Film||Amorphous Silicon||a-Si||12.5||Thin-film has many advantages over crystalline silicon due to the flexibility (non-rigid) of the end product.|
|Thin-Film||Cadmium Telluride||CdTe||17.3||First Solar is the leader and uses this technology. Thin-film has many advantages over crystalline silicon due to the flexibility (non-rigid) of the end product.|
|Thin-Film||Copper Indium Gallium Selenide||CIGS||20.3||Challenging process used by Solyndra in a tubular final form. Solyndra declared bankruptcy in 2011. HelioVolt in Austin, TX is developing a method of manufacturing CIGS.|
|Thin-Film||Dye-sensitized Solar Cell||DISC||11.4||Evolving technology included here due to it's affinity to thin-film.|
|Multijunction aka Tandem||Multijunction Polycrystalline||43.5||New and exciting technology that layers different materials to capture multiple wavelengths of light (infrared, visible, ultraviolet) thereby increasing efficiency. Max theoretical efficiency is 87%. Higher price and lower price-to-performance ratio has limited their use.|
|Hybrid / Emerging||Organic||8.3|
|Hybrid / Emerging||Organic Tandem||8.6|
|Hybrid / Emerging||Quantum Dot||5.1|
This is not intended to educate a consumer on how a solar power system works, it’s a pure discussion of the different approaches and technology used to convert photonic light to usable electrical energy.