What Is A Solar Panel And How Does It Work? Solar Panel FAQ
What is a Solar Panel?
Solar Panels are used to convert the sun’s rays into energy that is used to generate electricity. Each panel is constructed from solar cells that are fixed together on a semiconductor lattice.
Solar cells are photovoltaic devices, so called because they generate electricity from light.
Photovoltaic cells in the form of solar panels convert sunlight into an electric current by absorbing photons of light and using them to directly excite electrons across the cell’s wider surface area.
Solar cells convert sunlight into electricity by exciting and moving electrons
The excited particles then spontaneously emit negatively-charged electrons as they return to their lower energy or ground state. This flow of negative charges is what generates an electric current in the circuit.
Solar cells are made from layers of organic semiconductors that are coated with a photosensitive material, which is then exposed to light.
The most common types of solar cells in the market today are silicon, gallium arsenide, and cadmium telluride. Different solar panels are used for different applications.
For example, thin film solar cells work well in extreme environments like the space industry. They are also used in some military applications due to their higher resistance to heat.
The two main types of solar panel for domestic use are :
Monocrystalline Silicon
Polycrystalline Silicon
What is a Solar Panel System?
Solar panel systems include the following main components:
- Solar panels which convert solar radiation into DC (Direct Current) power.
- A solar inverter converts this DC power into AC (Alternating Current) power, which can then be used to run appliances and electronic devices.
- A battery bank stores excess energy generated by the panels so that it can be used later when sunlight intensity is lower or there is no sunlight at all (optional for a grid-tie system and necessary for an off-grid solar system.)
What goes into as solar system?
What is a grid-tie solar electric PV system?
In a grid-tie solar system, the solar panels are connected to the grid. Electricity is generated by the solar panels and then fed into the electrical grid through an inverter.
Power can also be drawn from the grid and the two flows are monitored by a net metering mechanism that identifies the amount of power generated by the system.
Do I need to worry about my roof type when considering solar panels?
Solar panels can be installed on any type of roof. The only consideration is the weight bearing capacity.
Normally this is not a problem because solar panels themselves are very lightweight and the mounts used for solar panel installations are designed to bear and spread the weight of the panels across the load-bearing beams.
How long does it take to install a Solar Panel?
It depends on several factors such as the types of roofing, whether it is flat or sloped, and also the extent of the wiring work needed.
Normally you should expect about 1-3 days to mount your panels and connect to your main electrical circuit.
What should I know before deciding to go solar?
Below are some considerations when deciding whether or not to go solar:
- What is my roof type?
- Do I have an adequate roof space for solar panels?
- Do I have access to the proper wiring for connecting with the system?
- Is my home in a location where there is good sunlight (peak-sun-hours)?
- What are the incentives and tax rebates for going solar?
- Do I know about the costs of ownership and solar panel maintenance?
- Do I have an adequate budget for going solar – what does it cost?
Which type of solar panel is most efficient?
Monocrystalline solar panels have the most efficient output
The answer is a monocrystalline silicon panel. This type of panel is made from a single crystal of silicon, which has the best chance of maintaining the crystalline structure through annealing and during subsequent high temperatures beyond typical panel operation.
These panels are more expensive than their polycrystalline counterparts, but they also have a higher efficiency rating because of the single crystal structure.
Why now is the perfect time for homeowners like me to invest in solar panels?
Solar panels have been around for a long time, but they’ve only recently become affordable.
The federal government offers tax credits and rebates that can help cover the cost of solar panel installation.
Homeowners who are eligible for the renewable energy tax credit will be able to use it to receive 22% back on their personal taxes in 2021.
The government also offers grants and other types of incentives that are available to people who go solar. These programs help make the decision even easier by providing some financial assistance and support from government and state agencies.
The benchmark used to assess the viability of a solar system for any location is to calculate the payback time, which is the number of years needed for the system cost to be paid back with electricity savings.
For any location, it depends on the size of the solar panel arrays and the peak-sun-hours.
Worked Example: Consider a solar electric PV system of 5000 watts in Orlando, Florida:
- City: Orlando, Florida
- What solar system power: 5kW
- Cost of solar system Florida 2021 = $2.64/watt
- Solar installation capital cost = $13200 – 22% federal tax credit = $10296
- Irradiance for Orlando, Fl = 1806 Peak Sun Hours
- Power produced by solar panels = 1806 x 5kw = 9030kWhrs (kilowatt-hours)
- Orlando residential electricity cost per kW = 11.11 cents/kWh
- Savings each year= solar production x elec. cost = 9030 x 0.1111 = $1003
- Solar payback time Tampa, Florida = solar cost/yearly savings = 10296/1003 = 10.26 years
How many solar panels do I need?
Number of solar panels depends on energy usage and peak-sun-hours
There are a few factors that contribute to determining how many solar panels you need. They include the square footage of your roof area, the the amount of sunshine where you live, and the electricity usage for your household appliances.
One of the most important considerations when determining how many panels you need is whether your roof has enough space for additional ones.
There are also some other factors that could limit your ability to place more solar panels, such as zoning regulations or roof height limitations.
A major factor you need to consider is your location’s climate. Where you live determines the amount of sunlight you receive throughout the year. This is measured in kWh/m2/year or peak-sun-hours.
If it’s a cloudy day, then your solar panels won’t be able to produce much energy for your home to use. Conversely, if it’s a sunny day, then you’ll probably have more energy than what you need.
Calculate how many solar panels needed for the home
In the calculator that follows you’ll need to input the solar panel wattage in kW. So, for instance, 0.275 watts would be typed as 275.
Solar electric PV systems can lose power through heat, inverter losses, and cable losses – the calculator will account for these losses.
The Global Solar Atlas website we used earlier is also linked on the calculator. Just enter the irradiance value that relates to your location.
The calculator will tell you approximately how many solar panels you would need to cover your energy requirements.
Please Note: This is for guidance only. It’s not the same as being guided by a professional installer.
What happens if I run out of electricity from the solar panels during the day?
If your home appliances consume more power than the solar panels generate, then you can draw from your local utility company’s grid.
This is called a net metering system – it measures how much power flows between your solar system and the grid. Your solar panels are only capable of producing energy during the day, so if you run out of energy during the day, you’ll be able to draw from the utility company’s grid.
What does a solar panel system cost?
It varies according to state. The average for 2021 is $3 per watt installed. The price per watt has been decreasing steadily over the years and is expected to continue to do so.
The table below shows average wattage needed for the average home and the cost per watt installed for 11 states picked at random:
|
State |
Peak-sun-hours |
Solar required for 100% energy used (kW) |
Installation price Per Watt ($) 2021 |
|
4 |
14.33 |
2.45 |
|
|
6 |
6.59 |
2.68 |
|
Florida |
4.25 |
12.76 |
2.61 |
|
3 |
11.89 |
3.03 |
|
|
4.25 |
15.07 |
2.92 |
|
|
3 |
7.55 |
3.13 |
|
|
6.5 |
10.94 |
2.62 |
|
|
3.25 |
7.44 |
2.83 |
|
|
4.25 |
14.26 |
2.67 |
|
|
4.75 |
13.90 |
2.74 |
|
|
5.75 |
10.58 |
2.57 |
The reason for reducing costs is that increase in scale as the demand for solar energy increases. Since there is more competition, costs are driven down and more people can afford to buy solar panels.
The recent drive for renewable energy will ensure that the prices will continue to drop. The price per watt in 1995 was $7.34 but had dropped to $3.49 by the year 2007.
Solar energy is becoming an affordable alternative to many people as it becomes more commercially available and popularized by government incentives designed to drive down the initial cost. These incentives are likely to continue as President Biden recently announced a push for renewable energy installation through to 2030.
As other renewable sources of energy are developed, for instance, a combination of wind and solar power, then the price will become even lower because there will be more competition on scale.
Can I get a federal solar tax credit?
Who qualifies for a federal solar tax credit?
Any US home owner who pays taxes is eligible for the solar tax credit.
This is a federal incentive that covers a percentage of whatever you spend on a solar system. The credit applies when you purchase and install a qualified solar system, such as a solar electric system, on your residential property.
What are the present solar tax credit incentives?’
The US federal government currently offered a 30% investment tax credit for solar installations from 2019. This incentive only applied to residential systems and dropped to 26% of the cost in 2020.
It was due to phase out completely by 2021 but was extended at a reduced rate of 22%. States may offer additional incentives to homeowners, so be sure to ask about any state or local tax credits that apply in your area.
What are grid-tied systems and stand alone systems?
Grid-tied systems are connected to the utility grid, which provides electricity during peak hours that solar panels cannot produce. Solar installations can tap into this energy when demand is at its highest.
Stand-alone systems, on the other hand, do not connect to the utility grid and use a battery for storing power from the sun or other renewable sources when there is an excess of energy.
How is a grid-tie different from a stand-alone solar system?
Grid-tied systems are more efficient and provide reliable power – they cost less than stand alone systems.
Stand alone solar system are more costly because they require additional equipment in the form of home energy storage batteries, which provide autonomy from power outages.
Grid-tie solar systems can also use batteries which can provide power for hours or days in the event of a power outage.
How much electricity can I expect from my solar panels?
The amount of power provided by a solar system depends largely on the location (peak-sun-hours) and the total area of your solar panels. If you live in an area that gets a lot of sun, then your solar panels will produce more energy, all else being equal.
Installers us a simple formula for quick estimate of solar power generation per year:
Solar panel power rating x peak-sun-hours/year (irradiance) = watt/hours
Example: How much power in kHh will a 5000 watt solar system in Orlando, Florida will generate over a year?
To work this out we need to know the irradiance for Orlando using this site.
Irradiance is measured in kWh/m2/year, also known as peak-sun-hours
Energy generated for the year will be:
5000 watts x 1806 peak sun hours = 9030 kWh per year (or 24 kWh/day)
If your home is in a cloudy area, then you won’t get as much energy from your solar panels because the sun is not always shining brightly enough to produce electricity to power your appliances and lights.
Do I need an installer or do I install my own solar panels?
It is possible to install yourself but it is easier to make use of the expertise of a solar company to take care of all the details, especially if you have a complex roof or want your solar system to be integrated with other systems on your property.
Homeowners can save a lot of time and money by working through an installer who installs and maintains all types of solar panel systems on residential properties.
What are the environmental benefits of solar power?
Solar power is clean, it doesn’t emit greenhouse gases or other pollutants. It doesn’t need fuel and can be paid for with capital savings instead of a fuel bill.
What are the benefits of solar as opposed to fossil fuels?
Solar is advantageous in that it is financially independent from petroleum products.
It’s environmentally friendly and produces no green house gasses or other pollutants. There are also tax credits for those who make the switch to solar energy.
What is the difference between a crystalline cell and an amorphous cell?
Difference between crystalline cells and amorphous
Crystalline cells are the traditional, older version of solar technology. Amorphous cells are newer and are very useful in certain applications. For one thing, they are incredibly flexible so can be put to good innovative use.
Crystalline solar panels are still the preferred choice of residential home owners because they’re more efficient and reliable than amorphous solar panels. See efficiencies and other information in the table below:
|
Characteristics |
Monocrystalline |
Polycrystalline |
Thin Film (amorphous) |
|
Composition |
One crystal |
Multiple crystals |
Thin silicon layers |
|
Color |
Black |
Blue |
Multiple – varies |
|
Efficiency |
17 to 23% |
10 to 14% |
5 to 6% |
|
Lifetime Duration |
25 to 30 years |
20 to 25 years |
15 to 20 years |
|
Manufacturing Process |
Complicated |
Easier |
Complicated |
|
Cost |
Expensive |
Cheaper |
Expensive |
|
Temperature Tolerance |
0 to 5% |
-15 to +5% |
-3 to +3% |
What is net metering and how does it work with solar panels?
Net metering is a billing system that credits customers for excess power fed back into the electric grid.
When a solar energy system’s generated electricity exceeds the home’s usage, the surplus electricity is sent to the electric utility grid and used by other customers in the area.
Each state have different solar buyback rates. Sometimes equal to the retail price and sometimes a little less. In several states the buyback rate for solar electricity is more than the retail rate, so it constitutes a great deal for solar homeowners.
When home usage exceeds a solar system’s production, the customer draws electricity from the utility company. This billing arrangement encourages renewable energy adoption because it is offset by lowered monthly utility bills.
How does net-metering work with solar panels?
What is a solar tracker?
A solar tracker is a device that follows the sun to produce maximum energy by efficiently moving the solar panels toward the sun throughout the day. Some models track the sun automatically while others require manual turning.
It can make a huge difference in output, as the sun’s irradiance varies a great deal across 24 hours – see below:
A solar tracker can improve output watts by up to 40%!
A single axis tracker is designed to follow the sun across the horizon and moves up and down on a single axis.
A dual axis tracker follows both the sun’s azimuth and elevation. It moves from east to west on one axis, and up and down on another.
A solar tracker can improve output by up to 40% and increase system life expectancy by as much as 2 times.
What is a solar tracker and how does it boost solar output?
How many multiple panels should I install?
Multiple solar panels connected together are called arrays.
Discover your solar saving potential
The number of panels you install depends on your specific energy needs. Most solar panels are rated by peak wattage, or the maximum amount of power that can be produced.
The average solar panel is effective for small installations such as a boat or RV and is approximately 30 watts. Larger installations should be sized properly to provide enough energy for your household’s electrical demands.
Solar panel output mostly depends your location and the latitude of your location. Placing panels on a roof that faces due south will maximize output. The average panel’s output is approximately 3 watts per square foot.
More information on multiple solar panels: https://www.solarempower.com/which-type-of-solar-panels-are-best/
What is the life cycle of a solar panel?
What is the life cycle of a solar panel and when should I expect power production from my panels to stop?
Solar panels normally come with a warranty of 20 years. Some manufacturers offer a 30-year warranty, while some offer 25-year warranties.
The life expectancy of the panels varies from panel to panel, but is typically related to how much power they produce daily and their exposure to the elements.
Renewable energy systems are designed to last 25+ years when properly maintained and monitored by skilled professionals.
However, solar panels will go on generating electricity for the next 20 to 25 years past their warranty period, depending on whether the solar panels are still in good condition and whether they are properly used.
How much energy can I expect my solar panels to produce over their entire lifetime?
That depends upon the orientation of your roof, the condition of your panels, and what percentage of sunlight they receive. Let’s assume a lot of averages and do a calculation:
Using the previous calculation for Orlando, Fl:
5000 watts x 1806 peak sun hours = 9030 kWh per year (or 24 kWh/day)
If we multiply the annual energy production by 30 years we get 270900 kWh.
However, output efficiency typically reduces by about 0.7% each year, so it’s a little more complicated than that! Even so, that’s an awful lot of free electrical power.
Why do I need an inverter and how is it different from a charge controller?
Does every solar system need an inverter?
An inverter is required to convert the direct current (DC) power generated by a solar panel into alternating current (AC) power usable by a home’s electrical system.
A solar charge controller is used to prevent a battery’s overcharge.
A solar storage battery or solar battery stores the energy collected by a solar panel and can be used at night or during cloudy days. Storage batteries include lead-acid, nickel cadmium, and lithium batteries, which vary in price and performance.
What is the life cycle of a charge controller and how often should I replace it?
Charge controllers are the electronic components that monitor and control a battery’s voltage. They determine whether the battery is being charged or discharged, as well as when the battery should be charged and how much time to allow it to charge before stopping.
They are generally good for 10 to 12 years before losing efficiency and wearing out.
How long will a charge controller last?
Where can I buy a solar inverter?
Solar inverters convert the DC power from solar panels into AC power which can be used in your home. They can also include a secondary DC circuit which is used to charge any batteries you might have in case of low levels of sunlight or for night use.
You can buy a solar inverter from various retailers – including Amazon, eBay, and Alibaba – but it’s best to research your purchase beforehand so you know what to expect when it arrives at your door!
What are good quality solar panels, complete with brand information and link to the manufacturer’s website?
Solar panels are great for powering your home as well as other electronic devices, but the quality of the solar panels can make all the difference.
Solar panels come in a range of types and sizes. Not all solar panels are created equal so it’s important to do your research before you buy!
The best quality solar panel manufacturer is one that has been around for a long time and shows an enduring commitment to providing high-quality products with competitive prices.
The best companies also educates their customers about how to take care of their product and offers excellent warranty protection so you won’t be paying for anything out-of-pocket if something goes wrong.
SolarDirect – since 1986
What are the benefits of solar panels?
Most of the benefits are financial, beginning with the advantages of the savings on your energy bills, and including:
- Using free sunlight as a source of heat and electricity
- Lowering your environmental impact because solar panels reduce carbon dioxide emissions from your home.
- Being able to harvest and store energy for days, months, or even years
- Reducing your carbon footprint by contributing to renewable energy sources.
There are also additional benefits that many people are unaware of, such as the fact that solar panels can be made of recycled materials – a factor in their being more sustainable than other types of equipment.
The environmental benefits include:
- Reducing greenhouse gas emissions by using a more efficient alternative to fossil fuels.
Is solar panel installation difficult?
Installing a solar system is not too difficult but is best done by a professional installer or solar company. The main components are a solar panel installation kit, a racking system and an inverter.
What is the difference between an inverter and a battery?
- A battery stores electricity that has been produced from the solar panels, it also supplies power when there is no sun.
- An inverter changes the DC electricity into AC electricity which you can use in your home.
Is it possible to live off grid with a solar system?
Yes, technically it is possible to do this. You would need at least a 2kW solar system (5 or 6 x 100 watt panels), and the battery bank would also need to be of substantial size.
Also the solar panels would need to be on your roof so that you were able to capture all of the sun’s rays year round. It will be easier in the summer months than the winter months because in winter you won’t get as much light per day.
Off grid solar systems need some kind of energy storage system to help make sure that you have enough electricity (batteries, such as charged by the sun during the day) when things get dark or when the sun is not shining.
A solar charge controller (which regulates how much energy your battery receives from the panels) is often included in off grid solar systems.
What is the best battery pack for living off grid with batteries?
Lithium based solar storage is cheaper over the longer term
Lithium Polymer (Li-Poly) batteries are the best for living off grid. They will last a lot longer than all lead acid batteries. Lithium Polymer is also known as Lithium Oxide and Li+O2 .
There are three main types of lithium polymer batteries:
- Lithium ion polymer battery or LiPo (polymer cells with cathode material but not anodes).
- Lithium iron phosphate (LiFePO4) or Lithium Iron Phosphate (LiFeP04) or LiFePO4 .
- Lithium manganese oxide (LiMnO2) or LiMnOs.
The lithium poly is a very good battery, but the problem is they are costly to manufacture and are not used much in small battery packs in off grid living because of their cost.
The cheaper lead acid batteries don’t last as long as the lithium variations, but they have a much-reduced life.
The LiFePO4 batteries can be charged and discharged more times than the others – up to 5000 cycles if discharged to 80% capacity.
Renogy Solar Storage Batteries
This might be a good choice for many applications, but if you are considering using it for off grid living with renewable energy – the cost is still high compared to the other options.
The benefit of having a lithium battery over a lead acid is that it can be discharged deeper without impacting its ability to hold a charge.
Lithium batteries do cost more than lead acids, but with the newer technologies they are now comparable in price to small lead acid batteries. Lithium phosphate batteries also will not freeze or explode.
