Monocrystalline photovoltaic electric solar energy panels have been the go-to choice for many years. They are among the oldest, most efficient and most dependable ways to produce electricity from the sun.
Each module is made from a single silicon crystal, and is more efficient, though more expensive, than the newer and cheaper polycrystalline and thin-film PV panel technologies. You can typically recognize them by their color which is typically black or iridescent blue.
How Monocrystalline Cells Are Made?
As the name implies this type of solar panel are unique in their use of a single, very pure crystal of silicon. Using a process, similar to making semi-conductors, the silicon dioxide of either quartzite gravel or crushed quartz is placed into an electric arc furnace. Heat is then applied and the result is carbon dioxide and molten silicon. This simple process yields silicon with one percent impurity, useful in many industries but not the solar cell industry, which requires a much higher purity level.
This is accomplished by passing a rod of impure silicon through a heated zone several times in the same direction. This procedure "drags" the impurities toward one end with each pass. At a specific point, the silicon is deemed pure, and the impure end is removed.
Next, a silicon seed crystal is put into a Czochralski growth apparatus, where it is dipped into melted polycrystalline silicon. The traditional way of adding boron, is to introduce a small amount of boron during the Czochralski process. The seed crystal rotates as it is withdrawn, forming a cylindrical ingot of very pure silicon.
Wafers are then sliced out of the ingot, then sealed back to back and placed in a furnace to be heated to slightly below the melting point of silicon (1,410 degrees Celsius) in the presence of phosphorous gas. The phosphorous atoms "burrow" into the silicon, which is more porous because it is close to becoming a liquid. The temperature and time given to the process is carefully controlled to ensure a uniform junction of proper depth.
Benefits of Monocrystalline Solar Panels
Determining what is an advantage or a benefit is a relativistic exercise and in this case the base of reference are the other types solar panel technologies. With this caveat in mind, here are some good reasons why many people choose Monocrystalline solar technology:
Monocrystalline solar panels are first generation solar technology and have been around a long time, providing evidence of their durability and longevity. The technology, installation, performance issues are all understood. Several of the early modules installed in the 1970's are still producing electricity today
2. Embodied Energy
While thin-film solar panels offer a lower level of embedded energy per panel, the fact that more panels are needed somewhat negates this aspect, especially given the extra mounting rails sometimes needed. Embodied energy refers to the amount of energy required to manufacture and supply a product.
3. Other Environmental Concerns
Some thin film solar products uses cadmium telluride (CdTe) . Cadmium is a heavy metal that accumulates in plant and animal tissues. Cadmium is a 'probable carcinogen' in humans and animals. While cadmium telluride doesn't pose a threat while the panel is in service, disposal of this toxic waste when the product reaches the end of its life comes at large cost and suitable facilities which is why firms like First Solar offer their own "end of life" recycling program to take care of disposing this material. Monocrsytalline solar panels are not hazardous to the environment.
4. Greater Heat Resistance
Like other types of solar panels, monocrystalline solar modules suffer a reduction in output once the temperature from the sunlight reaches around fifty degrees Celsius/a hundred and fifteen degrees Fahrenheit. Reductions of between twelve and fifteen percent can be expected. This loss of efficiency is lower than what is typically experienced by owners of PV panels made from polycrystalline cells.
5. More Electricity
Besides producing more electricity per sqm of installed panels, thereby improving your cash flow (from either a reduction in your electrical bill or from the sale of the electricity or in some areas both), for those who are "going green" and are concerned about the environmental impact of solar panels, monocrystalline panels reduce the amount of electricity needed from local power plants, reducing the dependence on fossil fuels. The greater benefit is a reduction in the use of limited fuel sources and greenhouse gases being pumped into the environment.
A corollary of the durability and longevity of this type of solar panels is that in areas where there is an established track record of performance (e.g., in Germany), we are able to obtain bank financing or related Funding Agencies of up to 80% - 90% for our projects, which is certainly a big reason why Germany has the largest installed base of solar panels in the world.