Solar Panel

Energy System Company® PV Solar modules offer models ranging in size from 5Watt to 300Watt. These modules are designed for use in a wide array of off-grid and grid-tie Solar System. These A-Grade panels are built using the highest quality components to ensure the best performance.

All modules have a power tolerance +5/-5% & are backed by 20/25 years warranty. The high performance cells are encapsulated in Ethylene Vinyl Acetate – EVA & placed between high transparent low iron tempered glass & a durable Tedlar Polyester Tedlar – TPT backsheet. The panels are framed using heavy-duty anodized aluminum frames, providing exceptional panel rigidity.

All modules are produced in ISO9001:2000 certified factories & are subject to triple-level quality control & testing procedures before they leave the warehouse – ensuring a high quality & consistent end product. Each panel has a ID number for tracking purposes.

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 The seed crystal rotates as it is withdrawn, forming a cylindrical ingot of very pure silicon.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.

Efficiency

Currently, Sun Power – USA manufacturers the most efficient monocrystalline solar panel – with an efficiency of 22.5 percent. In June 2010 they broke the world’s record for commercially produced solar cells at 24.2%.

According to various researchers, it is not theoretically possible to convert more than 29 percent of the light into energy using crystalline solar cells. Realistically, the limit for a PV panel is likely closer to 24 to 25 percent because of factors like heat, said Tom Werner, the CEO of Sun Power, during a briefing with reporters in June 2010.

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 is the other types solar panel technologies. With this caveat in mind, here are 8 good reasons why many people choose monocrystalline solar technology:

1. Longevity

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. Single crystal panel have even withstood the rigors of space travel!

Some other solar websites suggest that single crystalline solar panels can last up to 50 years. According to solar engineers I speak with even though this may be possible, there will be a slight drop off in efficiency of around 0.5% on average per year. So although this type of solar panels can last a long time, there will come a time when the lower efficiency makes it economically desirable to replace the panels especially as the efficiency of newer panels continues to increase.

Note: Most performance warranties go for 25 years, but as long as the PV panel is kept clean it will continue to produce electricity.

2. Efficiency

As already mentioned, PV panels made from monocrystalline solar cells are able to convert the highest amount of solar energy into electricity of any type of flat solar panel. Consequently, if your goal is to produce the most electricity from a specific area -e.g., on a roof this type of panel should certainly be considered.

Consequently, Monocrystalline panels are a great choice for urban settings or where space is limited. As a developer of PV rooftop installations in Germany, buying or leasing roof space is a significant cost of the whole project and so you want to be able to produce as much electricity you can from this valuable resource.

3. Lower Installation Costs

The cost of solar panel is typically around 60% of the cost of a fully installed solar power system, with installation being a significant cost component. Although I haven’t confirmed this yet, one installer in Australia – who sells and installs several types of solar panel has said that some amorphous thin film panels actually need more mounting rails and take longer to install; adding to the overall cost of the system. Additionally, they reported instances where home owners have had to rip up all their thin film panels and sell those at a loss in order to boost the size of their solar power system when they switched over to monocrystalline solar cells to produce more electricity as their usage increased over the years.

4. 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.

5. 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 panel are not hazardous to the environment.

6. 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.

7. 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.

8. Bankability

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 of up to 90% for our projects, which is certainly a big reason why Germany has the largest installed base of solar panels in the world.

 

Disadvantages of Monocrystalline Solar Panels

 1. Initial Cost

Because PV panels made from single-cell silicon crystals the process of making them is one of the most complex and costly ones around. Good silicon feedstock is expensive -although less so in 2010 than it has been for a a while and the cost of making a single pure crystal is time-consuming and therefore costly, PV panels from monocrystalline solar cells generally cost more per panel than competing PV technologies.

However, instead of comparing costs on a per panel basis, or even on a per kWp basis … I recommend you look at the investment on a per kWh basis over the expected life of the panel. Based on the analyses I’ve seen of various project proposals, monocrystalline solar panels are typically the most economical over the life of the installation.

2. Fragile

You should take into consideration that solar panels can be broken by tree branches or by objects carried by a strong wind. Generally, the solar panels are covered by a safety glass that helps protect the panels from damage … but if you are in an area where you are likely to experience roof damage due to falling / flying objects besides the obvious of making sure your solar installation is insured at replacement value, you should ask your solar consultant / advisor regarding susceptibility to such damage to make sure that you don’t lose your power when you might need it most – i.e., such storms usually cause major blackouts that sometimes can take quite a while to fully restore power to everybody.

How Polycrystalline Cells Are Made

The reason polycrystalline solar panels are less expensive than monocrystalline solar panels, is because of the way the silicon is made. Basically, the molten silicon is poured into a cast instead of being made into a single crystal.

This material can be synthesized easily by allowing liquid silicon to cool using a seed crystal of the desired crystal structure. Additionally, other methods for crystallizing amorphous silicon to form polysilicon exist such as high temperature chemical vapor deposition – CVD.

In the cast process, silicon pieces are melted in a ceramic crucible and then formed in a graphite mold to form an ingot. As the molten silicon is cooling a seed crystal of the desired crystal structure is introduced to facilitate formation.

Although molding and using multiple silicon cells requires less silicon and reduces the manufacturing costs, it also reduces the efficiency of the solar panels.

Efficiency

Generally speaking, polycrystalline panels have an efficiency that is about 70% to 80% of a comparable monocrystalline solar panel. The most efficient polycrystalline panels are built by Mitsubishi Electric Corporation. In February 2010, Mitsubishi set two world records for photoelectric conversion efficiency in polycrystalline silicon photovoltaic -PV cells, which was achieved by reducing resistive loss in the cells. The conversion efficiency rates have been confirmed by the National Institute of Advanced Industrial Science and Technology – AIST, in Japan.

Another one of the world records, which Mitsubishi Electric has now renewed for the third consecutive year, is a 19.3-percent efficiency rating for photoelectric conversion of a practically-sized polycrystalline silicon PV cell of 100 squared centimeters or larger, with the PV cell measuring approximately 15cm x 15cm x 200 micrometers. The rating is 0.2 points higher than the company’s previous record of 19.1 percent.

The second world record, achieved with the same technologies in an ultra-thin polycrystalline silicon PV cell measuring approximately 15cm x 15cm x 100 micrometers, is an efficiency rating of 18.1 percent, a 0.7-point improvement over the company’s previous record of 17.4 percent.

Currently the solar industry is investing lots of money in research and development to find ways to increase manufacturing costs and boost overall efficiency of the solar modules. As you can see from the work done by Mitsubishi, these improvements are primarily incremental in nature and are more on the manufacturing side than on the efficiency side.

Benefits of Polycrystalline Solar Panels

 

1. Lower Per Panel Costs

Are much simpler to produce, and cost far less to manufacture. This makes them much less expensive for buyers, especially those with small to medium sized roofs.

2. Durability and Longevity

The durability and longevity are comparable to their monocrystalline cousins – namely at least 25 years. Polycrystalline solar panel modules could put solar power into the hands of people who could not afford the polycrystalline cells.

3. Environmental Enhancements

Besides being able to produce energy from the sun and thus help reduce greenhouse gases and related environmental problems of extracting fossil fuels – e.g., the BP oil spill, coal mining accidents, geo-political resource wars, etc., some polycrystalline solar panel manufacturers – e.g., Mitsubishi go the extra mile by inventing new technologies that eliminate expensive soldering – which also contains lead making these panels even more environmentally friendly.

 4. Lower Electric Bills

Any solar system can and probably will result in a lower electricity bill. Even though the amount of electricity produced from a polycrystalline solar panel is less than from a monocrystalline panel – so are the costs … so you have to fine tune your analysis to see which one has the better payback over the time frame of your analysis – e.g., 20 years in Europe – which is usually the time period of the Feed in Tariffs.

Disadvantages of Polycrystalline Solar Panels

 

1. Lower Efficiency

Polycrystalline solar modules are less efficient than those made from a single crystal.

2. Fragile

Polycrystalline solar panels are somewhat fragile, and can be broken if hit by a falling branch or reasonably heavy object flying through a strong wind.

3. Competitive

There is strong price competition between polycrystalline manufacturers, and this can be both a good thing – in that it tends to keep prices low or a bad thing – some manufacturers may not be able to withstand the competition and won’t be around to honor their product or performance warranties.