Home Solar Energy Guide: Part III

Home Solar Energy Guide: Part III

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In Part II of our Home Solar Energy Guide, we took a brief look at different types of solar panels. Read on to learn more about the differences between monocrystalline, polycrystalline, and amorphous solar cells – in manufacturing, price, and performance.

The cost of photovoltaic panels has dropped dramatically over the last few years. At the same time, energy costs have climbed in many regions, and alternative energy incentive programs from local, state, and federal agencies help offset the cost of a home PV system. The bottom line? Using solar panels to offset your home’s electrical needs is more economically feasible than ever before.

But which type of panel is right for your home? They all convert the sun’s rays into usable electricity, so in most cases it comes down to the particulars of your home and budget. The main considerations are the amount of power you need to generate and the space you have available for a solar array.

Amorphous Silicon Solar Panels

Amorphous silicon photovoltaic cells are the cheapest to manufacture. They only produce about half the power of crystalline solar cells, which means the panels must be much larger to generate the same amount of electricity.

Amorphous Silicon Photovoltaic Film

Amorphous Silicon Photovoltaic Film

Amorphous silicon cells utilize non-crystalline silicon, which allows for a very thin and lightweight film within the solar panel – but the tradeoff is their lower efficiency. Amorphous cells maintain their ability to produce power under high temperatures (better than crystalline solar cells) so they may be used for certain specialty applications where heat is a concern.

Polycrystalline Silicon Solar Panels

Polycrystalline silicon photovoltaic cells are much more efficient than amorphous silicon cells. Individual silicon crystals are carefully arranged into larger, continuous “polycrystals”, unlike the non-crystalline film used in amorphous cells. The manufacturing process is more expensive, but each cell is capable of generating more electricity.

Polycrystalline Silicon Solar Panel

Polycrystalline Silicon Solar Panel – Note The Visible “Flake” Pattern

Polycrystalline solar panels are common for residential applications, since they offer a balance between cost and the space needed for the solar array. Polysilicon panels typically produce around 130 watts of electricity per square meter; they are recognizable by the flake or grain pattern visible within the PV cells.

Monocrystalline Silicon Solar Panels

Monocrystalline solar panels are the most efficient type available for residential use; they are generally a bit more expensive than polysilicon panels, but they generate the most energy while taking up the least amount of space. Monosilicon PV panels can produce up to 170 watts of power per square meter.

Monocrystalline PV Cell & Solar Panel

Single Monocrystalline PV Cell (left), Assembled Solar Panel (right)

As the name suggests, monocrystalline solar cells utilize wafers sliced from individual silicon crystals (as opposed to the “mosaic” crystals found in polysilicon panels). Monocrystalline solar panels can be distinguished from poly panels by the smooth appearance and even color of the cells.

Calculating The Efficiency Of Solar Panels

Monocrystalline Silicon Solar Panel

When figuring the amount of rooftop space needed to produce a given amount of energy, be sure to check the specifications of the particular panels you’ll be using. Remember that the efficiency figures above refer to a square meter of the PV cells themselves, not the overall area of an assembled solar panel.

As a point of reference, one of the most efficient solar panels currently on the market is the AC-250 from Massachusetts-based American Choice Solar. Each 39″ x 65″ panel is comprised of 60 monocrystalline silicon wafers that generate 250 watts of electricity.
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Check back soon for Part IV of our Home Solar Power Guide, where we’ll put all this knowledge into practice and look at some examples of actual solar power systems in action.