Solar power is the generation of electricity using solar energy. It consists of a series of chemical reactions, all of which happens in the solar panel. But how do they work?

A guide to solar panels

Photovoltaic solar panels are made up of photovoltaic (or PV) cells, which can be manufactured from a variety of materials; the most popular being crystalline silicon. These cells are produced by over 100 manufacturers across the globe, commercially available in four types. The type of panel appropriate for the customer differs according to their requirements – fortunately this is something the installer is qualified to discuss.

Below are the four main types of photovoltaic cells, along with a brief rundown of how each is made and their unique individual benefits:

Monocrystalline Silicon PV – These are the most commonly used panel types, accounting for approximately 93% of all solar modules sold around the globe. They are incredibly flexible in terms of project size, suitable for both large and smaller scale solar PV systems. This has lead to broad application and use across domestic and commercial installations alike, with some companies offering free solar incentives for using the technology.

Monocrystalline PV cells are produced when highly pure molten silicon forms a crystal, which is then cut into thin slices to comprise the basis of a solar cell. These slices are between 0.2 and 0.3mm thick, that are then cut into a hexagonal shape to optimise the module’s space. Monocrystalline cells are 13-17% efficient, making them the most efficient type of PV cell. They are therefore ideal for optimising smaller roof areas. However, the panels take more time and energy to produce which is reflected in their often high costs.

Solar PV panels on a home

Polycrystalline Silicon PV – Another commonly used panel type, polycrystalline PV cells are also produced from pure molten silicon. However, instead of being formed as a crystal, they are produced using a casting process. The silicon, having already being heated to an extremely high temperature, is cooled under controlled conditions before setting to an irregular multi-crystallised, or ‘polycrystalline’ form.

The silicon is then cut into 0.3mm slices to be used in the panel. Polycrystalline panels have a notable blue appearance, due to the anti-reflective layer which is applied to the cells to increase their efficiency. These cells have an 11-15% efficiency level which, whilst lower than their monocrystalline counterparts, is usually reflected in their cost. They are best used for a larger surface area in order to make the installation less expensive, suitable for both domestic and commercial solar PV systems.

Amorphous Silicon PV – PV cells comprising of amorphous silicon make up 4.2% of global market sales. This particular type of silicon is non-crystalline and therefore formed in an entirely different way to poly and monocrystalline PV. The semi-conductor material required for amorphous silicon is much thinner at only 0.5 – 2.0um thick (1um=0.001mm). The process therefore requires considerably less raw material compared with the production of crystalline silicone.

Amorphous silicon cells are 6-8% efficient, which is lower than crystalline PV cells. Due to this low generation-density, these types of PV cells are not currently suitable for residential installations. Whilst their lower efficiency levels mean that they require a larger surface area, the output is less affected by shading and higher temperatures.

Hybrid PV – Hybrid photovoltaic cells use two different types of technology. The most common type contains a monocrystalline silicon cell coated in an ultra-thin amorphous silicon layer.

Combining the advantages of both crystalline and amorphous PV cells, they perform well at high temperatures whilst maintaining higher efficiencies than conventional silicon cells. They are also more sensitive to lower and indirect light levels, with efficiency levels of often more than 18%. However, whilst they are more cost-effective, they do carry a higher cost.

Which to choose?

Personal circumstances and requirements are key things to consider when choosing solar PV panels. Is the system required for a domestic or business installation? What is the priority – cost or efficiency? When deciding on an installer, it’s always best to ensure that they are reputable and accredited by the Renewable Energy Association and the Microgeneration Certification Scheme. Remember that they are in a position to help find the best panel type for different requirements and should be willing to discuss all available options.

The PowerPort Solar Charger and Battery has been designed to harness the sun’s energy, shortening the process of transforming it into electricity by using photovoltaic cells (PVs). PVs convert sunlight into electricity that can be used immediately. The process is clean, fast, noiseless, and – thanks to Lenmar – easily portable. Here’s how it works. Light from the sun hits the solar cells. exciting electrons within the cell. Some of them break free, and channeled through a conduc (more…)

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Miniature PV Cells

The photovoltaic (PV) industry is on the verge of expanding into something really big… er… small.  Miniature PV cells are being developed to be used just about anywhere sunlight may strike – from fabric to windows to automobiles.

Thin film solar panels can truly offer solar energy to go!

They are so tiny and flexible, the hope is that they can be imprinted on just about anything.  As described in a recent New York Times article:

“The new technology is the work of a researcher and his colleagues who developed a way to print ultrathin, semitransparent and flexible cells on plastic, cloth and other materials. If the technology succeeds, it may provide the solar industry with alternatives to the fixed installations that are common today: cells may be printed on plastic rolls that could be unfurled for dozens of uses, or stamped onto fabric for T-shirts or other clothes that collect energy while worn.”

How thin film solar cells work

Researchers at the University of Illinois, Urbana-Champaign developed a technique by which to create ultra-thin solar cells only 1/10th the thickness of semi-conductor cells.  Semprius has licensed the technology and will begin a solar module pilot project in the next 12 months.  From its website:

Semprius is developing unique, patented technology that allows transfer printing of high performance semiconductors onto virtually any surface, including glass, flexible or rigid plastic, metal or other semiconductors.

Semprius technology offers an unparalleled ability to create novel devices and systems by liberating the semiconductor from its traditional rigid substrate. Very tiny circuits are efficiently and cost effectively transferred by the hundreds, and even thousands at a time.

The miniature PV cell technology is ground-breaking on a number of levels.  Its not only their thinness and flexibility that could change the solar panel market, but also their higher efficiency.  And… here’s the best part for most investors and consumers:  low cost.  By minimizing the thickness of solar cells, you reduce their expense.

The possibilities are endless: from windows to sun roofs (they are semi-transparent).  Any place the sun shines, you can be harnessing its power.

Perhaps in the next 5 years, we can say goodbye to the bulky PV solar panels and hello to sleek new miniature PV cells on a multitude of surfaces.