Hybrid solar lighting
is a new innovation in the field of solar energy use, which has caused quite a bit of excitement and buzz because of its simple design and ingenuity. While its primary focus is on industrial and commercial buildings, many environmentally-conscious homeowners are beginning to look at it as a viable source of lighting.
Rather than using solar panels, which collect solar energy as electricity, store that electricity, and use it to power lights throughout a building, hybrid solar lighting instead transmits the solar energy directly into the structure using optical fibers. By bypassing this intermediary step, hybrid solar lighting has a much higher efficiency.
Traditional solar panels are able to utilize approximately 15% of the sunlight they receive, and standard light bulbs lose the bulk of their energy in the form of heat — the end result is a total efficiency of about 2% of the original sunlight. By contrast, hybrid solar lighting systems are able to utilize as much as 50% of the original sunlight.
The benefits don't stop there, either. Hybrid solar lighting systems generate much less heat than traditional bulbs (the optical fibers are cold enough to be touched with no danger of burning), saving on cooling costs. They also yield indirect sunlight, meaning the light you receive is full-spectrum rather than the narrow band found in most light bulbs.
It is generally considered that there are three basic generations of solar cells, though one of them doesn't quite exist yet, and research into it is ongoing.
The first generation of solar cells are high-cost, high-efficiency. These solar cells are manufactured in a fashion similar to computers, involving extremely pure silicon, use a single junction for extracting energy from photons, and are very efficient, approaching their theoretical efficiency maximum of 33%. In 2007, first generation solar cells accounted for 89.6% of commercial production, though the market share of these solar cells are declining. The manufacturing processes that are used to produce first generation cells are inherently expensive, meaning that these cells may take years to pay for their purchasing costs. It is not thought that first generation cells will be able to provide energy more cost effective than fossil fuel sources.
The second generation of solar cells, which has been under intense development for the 90s and early 2000s, are low-cost, low-efficiency cells. These are most frequently associated with thin film solar cells, designs that use minimal materials and cheap manufacturing processes. The most popular materials used for second generation solar cells are copper indium gallium selenide, cadmium telluride (CdTe), amorphous silicon and micromorphous silicon.
A standard example of second generation cells would be the solar cells made by Nanosolar, which uses a special machine to print the cells at an extremely fast rate. Though these cells have only 10-15% conversion efficiency, the decreased cost more than makes up for this deficit, and it is thought that second generation solar cells will surpass first generation cells in market share sometime around 2010. Second generation solar cells have the potential to be more cost effective than fossil fuel, though this may not occur until 2015 or later.
