If you own a home or manage a business and you’re considering solar power as an alternative to the non-renewable energy supplied by your local utility company, you’re probably interested in learning which photovoltaic cells — the cells in solar panels responsible for converting light to energy, would be a good investment for your house or company. One of the first things you should know, however, is that there are several types of photovoltaic cells: monocrystalline silicone, polycrystalline silicone and several varieties of thin-film.
Whether you decide to install crystalline solar panels or thin-film silicon solar cells, you’ll be joining one of the fastest growing trends in the energy industry. Due to increases in the efficiency of photovoltaic cells, tax incentives by the Federal and state governments and renewable energy buy-back programs, solar energy doesn’t only represent cost savings for its users. It’s a moneymaker.
Choosing the Right Type of Solar Panels
While solar solutions are available to a vast range of property types, not every home or business is well suited for solar panels. There’s a lot to consider before you commit to your initial investment. Reputable solar panel installers will assess your property to help you decide about the viability of photovoltaic cells for your situation. Among the factors you should consider are:
- Climate – Contrary to popular belief, you don’t need to live in an area where the sun shines year-round to benefit from photovoltaic cells. Modern solar panel systems can convert ambient sunlight to electricity, even on cloudy days. However, the solar panels don’t function well when blocked or covered with snow. Additionally, during the winter, the days are shorter, providing fewer hours of sunlight. Therefore, you may rely more heavily on supplemental electricity provided by the power company, so your energy savings will be lower.
- Type of residence or business space – If you own a condo or rent space in a high-rise office building, you may not have the available roof area required to support solar panels. With this in mind, most residences require the higher-efficiency crystalline silicon solar panels due to space economy.
- Type of roof – Solar panels will work on most types of roofs, but they function better when they can be positioned for maximum exposure to the sun. Older roofs that are nearing their time to be replaced may not be good candidates for solar panels because removing and replacing solar panels can be an expensive process.
- Roof surface area – For both residences and businesses, the roof is the ideal place to set up solar panels. Businesses with a substantial amount of unused land may be better suited for grounded solar panels, but they’re not as common. Larger roofs allow for more panels to be installed, but they also are also part of larger buildings, which could mean the energy demands are also higher.
- Availability of net metering – Modern photovoltaic cell systems are usually connected to the power grid. When you are producing more electricity than you use, the excess energy goes into the grid. When the reverse is true, you draw from the grid. Net metering allows you to receive credits for surplus production. This is a tremendous benefit for solar homes and businesses in that it helps ensure continuous uninterrupted power to your location and allows you to garner savings.
- Projected cost savings – This is a calculation that lets you know when you’ll break even after the extended use of a solar energy system. It’s also a significant factor in determining whether you should choose crystalline silicon or thin-film solar panels.
- Crystalline vs. thin-film solar panels – Most solar panels fall into one of these two categories. While there are numerous manufacturers, makes and models of solar panels with varying costs, the products all serve the same function: They convert light to electricity. But how the two types of solar panels accomplish this task is somewhat different. There are pros and cons to both crystalline silicon solar cells and thin-film silicon solar cells, which we will discuss in the next section.
Crystalline vs. Thin-Film Solar Panels
If you’re someone who’s new to solar energy, crystalline and thin-film solar panels may seem similar, and in several ways, they are. But the processes used to make the monocrystalline, polycrystalline and thin-panel solar panels are each unique. They also all have varying performance properties. Before we explore the pros and cons of crystalline solar panels and thin-film solar panels, let’s examine what makes them different:
Crystalline Silicon Solar Panels
As the name would suggest, crystalline panels use a configuration of crystalline silicon solar cells to achieve the photoelectric effect. Crystallized silicon (c-Si) is categorized as a photoemissive material because of a particular behavior it exhibits when light is shined on it. With photoemissive materials, light excites and frees electrons.
Although they’re called “photoelectrons,” they are identical to all other electrons. The term means they were liberated due to a reaction with light. The photoelectrons are channeled toward a conductor, which produces an electric current. Crystalline silicon solar panels utilize two different types of crystals: monocrystalline and polycrystalline.
Monocrystalline silicon is produced using the Czochalski process, which results in high-grade, high-purity crystal silicone ingots. The monocrystalline ingot is cut into thin silicon discs, which are arranged into panels. During the shaping of the monocrystalline silicon wafers, a considerable amount of the material is lost, which makes this an expensive process. Monocrystalline silicon solar panels are efficient and tend to work better in warmer weather than their polycrystalline counterparts. They also have a higher wattage output than monocrystalline silicon panels when all other factors are equal.
The process used to produce polycrystalline silicon wafers is much simpler, and more cost effective. The silicon material is melted down, molded and then cut into the wafers for the panels. Polycrystalline silicon solar panels don’t work as well in warmer weather, but the overall cost of the panels is lower, making the initial investment outlay for the consumer lower than with monocrystalline panels.
Thin-Film Solar Panels
At the molecular level, thin-film solar cells (TFSC) work almost identically to crystalline solar cells. Light interacts with photoelectrons, freeing them from their source material and converting them into an electric current. Unlike crystalline photovoltaic systems, however, the photoemissive materials aren’t cut from crystals. Instead, photoemissive materials, like amorphous silicon — as opposed to crystallized, cadmium telluride or copper indium gallium selenide cover the substrate material.
Because the process is simple, it’s easier to mass-produce thin-film solar panels, making the cost low. Thin-film solar panels are not as efficient as crystalline panels, but that doesn’t necessarily mean they’re an inferior product. Efficiency is important, but depending on a number of other factors, TFSCs may provide adequate electricity for your level of consumption, particularly if you have the space to install them.
The Pros and Cons of Crystalline Silicon Solar Panels
For the purpose of this section, we will examine the pros and cons of the two types of crystalline panels — monocrystalline and polycrystalline — together, and point out the differences as they arise.
- Efficiency – Crystalline silicon solar panels are more efficient than their thin-film counterparts. Consequently, crystalline panels require less roof surface area to generate the same amount of electricity. Because bigger residences often have greater power demands, even locations with larger rooftops may require solar panels with higher efficiency ratings. Monocrystalline solar panels have an efficiency rating of 15 to 20%, which is about twice as efficient as thin-film solar panels that range from 6 to 8%.
- Typically, monocrystalline silicon solar cells are more efficient than polycrystalline cells because of the purity of the photoemissive material. Recent improvements in the process used to make polycrystalline silicon panels, however, have closed the gap between the two products’ viability.
- Degradation – All solar panels slowly lose their ability to convert sunlight into electricity over time. This makes sense since the job of the photoemissive materials is to shed electrons that can be used to produce current. Crystalline solar panels lose up to 0.5 to 1% of their efficiency per year. This can be a confusing piece of information since we just stated that crystalline solar panels have a 15 to 20% rating. The degradation is 0.5 to 1% of the original efficiency, so if a panel begins with a 20% efficiency rating, and degrades by 1% after a year, it will have a 19.8% rating — 1% of 20% is 0.2. Crystalline panels have a longer life expectancy over thin-film solar panels — they usually come with a 25-year warranty — but TFSC panels should still provide years of service after you’ve reached your break-even point.
- Adaptability to heat – Crystalline solar panels tend to work better in warm conditions than thin-film solar panels, with monocrystalline outperforming polycrystalline.
- Cost – With the higher efficiency of crystalline silicon solar panels comes a greater initial cost per panel. Monocrystalline silicon solar panels tend to be pricier than polycrystalline panels, but if you have limited roof space, they may be your best option. However, while the per panel cost tends to be higher, you may end up requiring fewer panels to offset your energy consumption needs. This results in savings on the number of panels purchased as well as the connecting materials and mounting brackets.
- Shade performance – Partial shading can cause some of the crystalline silicon cells to stop producing electrons, and overall efficiency is reduced. Again, monocrystalline silicon cells outperform polycrystalline silicon cells under low light conditions.
It’s also important to note that shade may be a factor in whether any type of solar solution is a good fit for your home or business. If you are located near tall buildings that block your roof from the sun for part of the day, solar may not be a financially viable option for you. However, don’t be discouraged if you have some blockage. Professional solar panel installers are often able to develop creative configurations to facilitate your needs.
The Pros and Cons of Thin-Film Solar Panels
There are several photoemissive materials used to make TFSC panels. As we did with crystalline panels, we will examine thin-film solar panels in the aggregate and only point out the differences when they apply.
- Cost – Thin-film solar panels are manufactured using a much less expensive process than either monocrystalline silicone or polycrystalline silicone solar panels. They are still less efficient, however, which means more panels will have to be installed to achieve the same electrical output. Few residences are suitable candidates for thin-film solar panels. Most homes don’t have the roof area to support a sufficient number of panels to achieve energy independence.
- Degradation – This can be considered both a pro and a con. While most varieties of TFSCs degrade slightly faster than crystalline silicone panels, the lower cost may make the shorter life expectancy less of a concern. Where crystalline silicon panels degrade at 0.5-1% per year, thin-film silicon panels are consistently closer to 1% per year.
- Shade performance – Because of their construction, thin-film solar panels are not as susceptible to issues with shading as crystalline solar panels.
- Efficiency – Thin-film solar panels are generally not as efficient as crystalline silicone solar panels, so more are required to produce the same electrical output. For residences or buildings with limited roof area, this may be enough, and they’ll need to go with one of the more expensive crystalline silicon options.
- Additional costs – Because more thin-film solar panels are required for the same electrical output, more mounting brackets and connection hardware is needed. So, while the cost per panel is lower, the savings are somewhat offset by the additional materials needed to connect a larger system.
- Shorter life expectancy – Crystalline silicon solar panels last longer and typically come with a 25-year warranty. Because thin-film solar panels degrade at a faster rate, their warranties are often shorter.
Talk to a Professional Solar Panel Installer
The advantages of installing a solar power system are numerous:
- Reducing or even eliminating electric bills
- Increased property value for both residential and commercial real estate
- Tax breaks from the federal government in the form of the Solar Investment Tax Credit
- State and local tax breaks for states like Virginia and Maryland as well as the District of Columbia
When doing research, property owners often make decisions about solar choices before they talk to an industry expert. This can lead to overlooking a logical choice — or walking away from energy savings altogether.
Thin-film solar panels might be less expensive, but they may not be adequate to fill your energy requirements. Monocrystalline silicon solar panels are the most efficient, but you may take longer to break even if you go this route.
Before you decide on monocrystalline, polycrystalline or thin-film solar panels, speak to a professional solar panel installer in your area. An experienced solar panel installer can measure your home, examine your current and predicted power usage and develop a model for your specific home or business that will save you money years into the future. In DC, MD or VA, contact Switch to Solar.