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Solar Panels

Solar panels are the foundation of modern photovoltaic power. They collect sunlight and emit an electric charge. The panels are commonly made of silicon. The chief expense in making a solar panel is purifying silicon from the silica, or sand, that it is most commonly extracted from. Silicon is plentiful on earth in the form of sand, but extremely rare in purities high enough to be used in the making of solar panels and other electronic devices. It is remarkably akin to the phrase “water water everywhere yet not a drop to drink.” The material is everywhere on earth, but not in usable form.

It is estimated that a solar panel must run for the first eighteen months of its life just to make up for the energy investment made in the silicon within the panel. There is as of yet no low-energy method available for reducing silicon to a pure enough form for use in solar panels. The upside is that solar panels do in fact “break even” in energy cost today.

For the first few decades of their development a solar panel would break down long before it produced the amount of energy that went into its construction. Today most panels break even at around the 2-3 year mark. They are designed to last over ten years, so they have at least 7 years of pure energy gain built into them. Note that the 2-3 year timeline for a panel to break even is a measure of energy only. In order for a panel to pay for the cost a customer pays for it, it usually has to run for around 5-6 years.

Ideas for improving solar panels abound. Some are trying to redefine the way we crystallize the silicon. Others are searching for new, lower cost alternatives to silicon. Some promising advances involve the use of thin film technology.

Thin film solar panels are “printed” rather than crystallized in the normal manner. They are currently less efficient than the bulkier solar panels, but they are less expensive to produce, even in this early stage in development. It is estimated that thin film solar panels only need to exceed 10% efficiency to be a competitively priced energy option. Compare that the traditional panels at a competitive efficiency of 25-30% and you begin to see the allure.

Another promising field of development is the field of multilayered solar panels. Silicon panels are limited in efficiency because they have a specific bandwidth of light that they can work with. There are other materials that react electrically to bandwidths above and below silicon’s. Layering a cell from the lowest bandwidth to the highest can achieve a product that can translate far more of sunlight’s energy into electricity than otherwise possible.

The cells have performed at 58% efficiency under laboratory conditions. Their chief impediment currently is cost of production. While they can absorb sunlight at a more efficient rate these cells are much more costly to produce. If the cost can be brought in line with other forms of solar power, tri layered solar panels could be the wave of the future.

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