In order for solar power to become a mainstream alternative energy option, economical and efficient devices are needed to make solar power an affordable energy source. With new thin-film photovoltaic cells the necessary breakthrough may be here.

It may not be exactly common knowledge, but we all have been told at some point in our lives that the solar power could eventually replace all other forms of energy on Earth. What we don’t realize is exactly how much energy the sun produces; that in one hour the Earth receives an equivalent amount of energy from the sun to satisfy all human energy needs for an entire year.

The problem with most solar energy capturing devices to date is that they are unable to convert a large part of the sun’s energy into electricity. Traditional silicon based solar cells have so far offered the best consumer efficiency at roughly 20%, but these cells are so expensive that many people can’t afford them. It is hoped that new thin-film solar cells that are much more economical than their silicon counterparts, with a 19.9% efficiency rate will be able to close the gap with consumers to make solar power an option in every household.

With the cost of high-grade silicon skyrocketing to nearly $500 per kilogram, finding an alternative to silicon wafer solar cells is a must to keep solar energy a viable alternative to coal-fired electricity. New thin-film solar cells use a thin layer of semiconducting material, which can be silicon, copper indium gallium selenide or cadmium telluride to collect the sun’s energy and convert it into a current at a much lower cost than older technology.

By using a thin film of material to harvest energy from the sun, solar cell makers are able to reduce the amount of semiconductor materials used by an astounding 98%. The new solar panels are equally efficient as silicon wafer technology but offer significant cost savings to the manufacturer and consumer.

Firms like Global Solar are using a blend of copper indium gallium selenide (SIGS) in their thin-film solar cell panels. They currently supply the military as well as outdoorsmen with portable chargers to allow the charging of small devices such as communications equipment and other electronics. They have recently opened a new factory in Tuscon and next year are planning to produce enough solar cells to produce 40 megawatts - the equivalent of 15,000 American homes. With the growing demand for alternative energy they hope more than double that amount by 2010.

Global Solar is hoping that many of their new thin-film solar panels will be used in large scale arrays, like many of the solar farms located in Arizona and California. Currently these power stations use silicon wafer cells, but with the lower cost of the new technology more of these farms are sure to spring up.

Many other companies are also jumping on the solar cell bandwagon, such as HelioVolt and Nanosolar, both who are using CIGS to reduce the cost of manufacturing photovoltaic cells. However, certain challenges need to be overcome, mainly the cost of new factories, creating efficient solar cells and making a long-lasting, reliable product.

While many CIGS solar cells are showing promise at being able to convert 20% of the sun’s energy into electricity, once the process is mass produced the efficiency generally begins to fall. This is due to the fact that the chemical processes used to create the cells are harder to control in larger amounts.

Sharp Electronics has taken a different approach to thin-film solar cells. Instead of using CIGS, they are pairing amorphous silicon with layers of crystalline silicon. They are planning to increase production to produce enough cells to create 160 megawatts this year with expansions planned for the future to bring the amount up to 1000 megawatts.

While many believe that eventually CIGS will replace traditional silicon materials, the executives at Sharp are predicting that the two will work in tandem to fill the various market demands. However, some would argue that the lower cost of thin-cell along with CIGS ability to withstand higher temperatures spells the end for silicon based photovoltaics.

The durability of thin-film solar cells has been called into question, which is why many companies like First Solar Inc., sell their cells encased in glass. This serves the purpose of protecting the solar cell, which has an estimated lifespan of 20-25 years.  First Solar also offers a recycling program for solar cells that are past their prime, so nearly 90% of the materials are reused.

Currently cadmium telluride solar cells are considered the most earth-friendly, as they require the least amount of energy (or fossil fuels) to produce. However, these types of solar cells only make up 30% of the solar energy market, while amorphous silicon cells command over 60% of sales and CIGS a paltry 1%.

Even with CIGS poor market representation, it is predicted that these solar cells will appeal to consumers with their high efficiency rate (up to 25%) and lower cost. New technology can incorporate photovoltaics within the glass of homes and buildings, making it easier than ever to convert to solar energy. Firms are also hoping to produce solar shingles for homes for even more energy savings.

With these new solar cell technologies already in production it is certain that solar power will soon be proving itself to the masses as an easy, economical way to harness the energy of the sun and reduce our dependence on fossil fuels for electricity.