Solar panels have been used on homes, businesses and other commercial operations since the 1970s. There were over 1.5 million solar power systems being used across Australia in June of 2016. That means green, clean electricity was being safely and reliably delivered to home and business as opposed to grid electricity. This is an inspiring prospect of what is to come.
How Do Solar Panels Work?
Solar panel arrays are fairly simple pieces of equipment. Generically, the solar panels use the protons from the sunlight to produce direct current (DC) energy. Direct current (DC) energy is then pushed to the invert which is then converted into alternating current (AC). Alternating current (AC) is the type of electricity that your home appliance and electronics can actually use. Without the inverter, the energy would be useless.
Often times, the extra energy that is produced by your solar panels is sent back to the grid. This is an extra incentive for solar panel array owners because your get an offset or paid for that extra energy. This is called a feed-in tariff (FIT). Although some solar panel arrays, the better ones have battery storage so that you can use the power at a later time. Maybe at night when the sun is not out and you need extra electricity when you cannot produce it. This is a better option than having to feed your excess back into the grid.
How Do Photovoltaic Solar Panel Systems Work?
The first thing you need to learn to understand how a solar panel system works is to learn about the photovoltaic effect. The photovoltaic effect is the creation of electricity based on the exposure of light upon a material. So, in this case, the sunlight is used to convert solar cells into electricity utilizing the protons.
The panels work best when positioned towards the North. The North gives them the most optimal angle to produce energy. When selecting your location you always want to make sure your do not have any trees, poles or other obstacles blocking the panels. Direct sunlight gives the panels the most optimal chance of production.
The other thing you need to take into account is your location. The weather will always play a part in how well your solar panel array produces. The clouds, rain and snow will most certainly cause a lack in production.
Types of Solar Cells, Panels and Arrays
A solar cell is typically made up of silicon and solar panels are made up of several solar cells. The cells are connected and backed by a plate that is then covered with glass in between an aluminium frame (the glass is protective and meant to withstand hail and other obstacle). This is the solar panel itself, which is often called a module. Multiple panels are called modules. This entire installation is known as a solar panel array.
The Solar Panels
Monocrystalline Panels: Typically a black colour with rather high efficiency over the multi-crystalline or polycrystalline models. Those are more of a bluish colour and tend to be more temperature tolerant. The difference in the models occurs in the manufacturing process relating to the silicon cells. In theory there probably is not much difference between the three models. The advantage in the end simply relates more to the overall construction of the entire array and every component involved, rather than the type of cell used.
Interdigitated Back Contact Solar Cells (IBC): Also called Rear Contact Solar Cells, is a type of solar cell that is known to achieve a higher level of efficiency by having all of the electrical contacts at the back of the cell. This allows the sunlight to freely make contact with the surface of the cell. Makes perfect sense, because there is nothing preventing sunlight from hitting the cell.
Thin Film Solar Cells: Another version of solar cells which are made on a very thin piece of photovoltaic material such as silicon with a backing such as glass or another metal for protection. Although not as efficient, this type of cell is used on larger projects and smaller projects from buildings to very small garden projects.
Solar Panel Efficiency
The efficiency of a solar panel is the amount of sun converted into electrical output via photovoltaics. The more power generated from the solar panel area, the more efficient the panels. This might even lower your installation costs. Let’s say you have a large roof top space. You might consider a more economical solar panel array that is not as efficient. You will be able to make up the difference in efficiency because of the space you have. The more panels the more power generated. These are the things you will want to think about as you plan for your system.
Another thing to consider is the effect of the warmth. As solar panels get warm, they are not as efficient. This means on a 115 day your panels are not going to be as efficient as an 85 day. Even though it may be just as sunny on both days the warmer day is not going to be as efficient because your panels will operate at less than optimal range.
Note that some panels operate better at different temperatures. This is why it is important to pay close attention to which panels are installed and you know what the power ratings are at standard conditions. Also, air should be allowed to circulate below the panels to help keep them cool. This will help regulate the temperature and keep them at their standard operating temperature.
Temperature is just one factor that influences the efficiency of your solar panels. Let’s take a look at some of the other factors that influence efficiency.
The angle of the pitch of your solar panel is another factor that will influence the efficiency of your panel or panels. Depending on where you are in the world and where you are mounting your panel the angle of the pitch is extremely important for maximum output. For example, in Brisbane, for the optimum output of the panels the pitch needs to be at 28 degrees. We use tilt-kits to make this happen. Your installer can help select the optimum pitch for your panel or array of panels.
Age is yet another significant factor worth talking about. As with most other products on the market, solar panels will degrade overtime. For example, manufactures will de-rate their panels to about 80% efficiency at year 20 of operation.
Shading can be a huge factor in the efficiency category of panels. Shadows caused by trees, clouds, buildings, and other obstacles can have a significant effect on the output of a panel and/or array. This is why placement was mentioned before. It is important that an analysis takes place to determine what time of shading patterns throughout the year can affect your panel or array. The effects can be devastating on your production. It is highly important you review this prior to install.
Another investigation that needs to take place prior to install is your placement. Remember, also stated previously, your panel and/or array needs to face as much North as possible. This means you need a roof that is facing as much East to West as possible. Note that there have been some studies produced which suggest a roof which is Western facing can be used for panels that have a very high afternoon electrical usage. If you have a low feed-in tariff (FIT) rate and you have a home or business in which you utilize a lot of afternoon power, then a Westerly face solar array may be your best solution. You would be optimizing on both ends. This is something you should considering discussion with your installer.
The loss of cabling can be an issue if you do not use the proper grade. This means you could potentially have a power outage of the entire system. It is important that you use high quality cabling between the solar panels, inverter, batteries, and other components. Do not skimp on the small stuff. Every piece of the install is important. You do not want to cause a larger problem do to something you do not think is significant.
Regular maintenance of your system is important. Although solar panels are self-sufficient and do not require much ‘cleaning’, it is recommended that after dust storms, major weather incidents, etc. you check the arrays to make sure the panels are clear of any debris that would cause a decrease in output. There are industry specific solar cleaning crews that you can hire to maintain your system if you would like. The rise in solar panel arrays around Australia has provided a new job industry for others. You might consider taking advantage of this if your array is large enough.
Inverters are one of the keys to solar panel systems. Without the inverter, we could not utilize the produced energy. Most inverters are reaching efficiency levels of about 90%. This means most of the direct current (DC) coming from the sun is being converted to alternating current (AC). This is excellent efficiency.
Last, be careful with the type of panel you choose. Do not underestimate the importance of high quality solar panels as we have discussed. Finalizing your system with poor quality components like a less qualified manufacturer of solar panels can seriously degrade your system leaving you with a very inefficient system.
Question and Answers
Are solar panels mounted directly to my roof?
Solar panel arrays are not mounted in a flush manner onto the roof. Although most panels look like that are mounted flush against a roof, there is actually space between the panel and the roof to allow for circulation of air flow between the two. This helps keep the panels cool during a warm day. Remember, the panels are more efficient if they are run at as low of a temperature as possible. If the planes were attached directly to the roof they would get too hot. The correct install helps ensure a more efficient production of electricity.
If the sunlight is blocked by trees, will this affect the output of my solar system?
In short, yes; however, as talked about before during your design phase an analysis would have been performed to determine what the shading cast would be like year round. Your system would have been set up to ensure you receive the most sunlight possible given your location. It is best if your location has no shading at all; however, if you do receive some shading it is recommended that between 9:00 am and 4:00 pm the shading does not exist. If possible, this is the optimal time for producing electricity; therefore, the least amount of shadows the better.
Most installer’s would have performed the analysis and provided you with the results of where on your roof they would propose to put the system. Along with that they would have showed you the shading results. Now understand, if there is some shading, they may be able to use a micro-inverter which allows them to maximize each panel by itself. This means one panel will not affect the efficiency of another. Although this is a more expensive option, it does allow for maximizing the solution.
I do not have a Northern facing roof, what are my other options?
Your first option could be installing panels in an Eastern and Western direction. This really helps to meet the morning and late afternoon needs of home owners and is becoming increasingly popular. However, the only way this option would be a positive one is if you have high output during those periods of time.
The other issue has to do with your roof aspect. You need to look at the pitch of your roof and shading specifically. The installer needs to outline exactly what type of production can take place based on your roof aesthetics. If the shading is too much, the array will not be worth installing and you could end up with a lack of production. The inverter needs to be in a location that allows for split panel locations. You just need to do a lot of analysis with your installer and look at your usage patterns as well as the feed-in tariff (FIT) factor.
It is an option and can work as long as the right pieces fall into place. It is certainly worth looking into.
I’m building a new house, can solar panels be built into the new home?
Adding solar panels directly into a home is the next generation of solar panels for residential housing and it is coming. In fact, Australia is already starting to print the next generation of solar panels called ‘organic photovoltaics’ (OPV). These are very thin film solar cells that can be used directly in roof tilling and sheeting. It may even be possible to add these films into windows and walls.
This type of technology may put conventional solar panel systems out of business. It will be interesting to see what this new technology develops into. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) helped develop a facility where the new printing of this solar film is being developed. Their goal is to focus on electronics right now and then start integrating the film into roofing systems.
Tesla Roof Tiles
Tesla has just set out on its own adventure developing a solar roof project. The roof is glass with solar cells inside which produce electricity. Apparently the cost is similar to regular roofs with the added benefit of electricity ($21.85/sq ft). However, you can even get the look for a Tesla Roof without the added benefit for $11 each if you just want the look and feel of the roof.