Solar Panel Efficiency: The Most Efficient Solar Panels In 2020
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If you follow any of the latest news in the solar industry, you may see the phrase “solar panel efficiency” come up very often.
I think (around) every 6-8 months there is a new world record for the ‘most efficient solar panel’. Just by jumping on google and searching I can see there is so much information on new “highest efficiency solar cells of 50%”.
But what does it all mean…
What is solar panel efficiency?
Is solar panel efficiency important?
Is it something you need to consider when buying solar panels?
How can you work out your solar panel efficiency?
And… Which solar panels are most efficient?
If you’re anything like me (a solar fanatic) then you will want to know the answer to these questions.
Honestly, there are arguments for both sides here. Some people may tell you that you don’t need to worry about solar panel efficiency, whereas others might tell you it’s actually more important than you think.
I’m here to give you my honest opinion, on why it shouldn’t matter as much as you think.
What does solar panel efficiency mean?
In short, solar panel efficiency is how effective a solar cell can convert sunlight into electricity using photovoltaics.
In much longer (and nerdy) terms: It’s a measurement of the amount of energy that is captured by the solar cell and transferred through the panels wiring and busbars where it is converted into AC electricity.
The higher the solar panel efficiency the more electricity you will generate. This will mean that you are getting more energy from your solar panel system at a cheaper price.
On average in 2020, solar panels have around 16-24% conversion efficiency. This is the industry standard.
For example: If your solar panel has a rating of 19% efficiency, then 19% of the sunlight that hits the solar panel will be converted into electricity.
What determines solar panel efficiency?
There are 3 main factors that really determine the conversion efficiency of the solar panel (cell).
The material the panel is made from
Solar panels can be made from several different materials. The most popular ones are:
Thin-film (silicon solar panels)
Out of these the best material is monocrystalline with an average efficiency rating of 20%.
These different materials all affect how well the solar panel can convert sunlight into electricity.
How reflective the solar panel is
When sunlight hits the solar panel, some light may be reflected back. When the light is reflected back, it’s not being absorbed or converted into electricity.
This causes a loss of energy conversion and makes the cells less efficient. The less the solar panel can reflect, the better.
This is why most solar panels are made from glass, as it does not reflect much light back. Again, this is also why all black solar panels usually have a higher conversion efficiency.
The wiring and busbar of the solar panel
When sunlight is captured by the solar cell, it gets transferred through the panels wiring and busbar to get converted into electricity.
The number of bus bars and types of wiring will all affect the efficiency rating. The more bus bars the better meaning it can convert more energy with less tension.
Factors that affect solar panel efficiency
There are many different factors that may increase or decrease your solar systems overall efficiency. Some of these factors are an easy fix. Others you will need to consider before you buy your solar panels. This will ensure you are getting the most from your budget.
Here are the main factors to consider:
Shading of solar panels
This is a pretty obvious one. Any shading that may naturally occur from trees, time of day, clouds etc will all directly affect your solar panel efficiency.
Also, this applies to dirt and soil that may collect on your solar panels from time to time. The dirt will obstruct the light from reaching the solar cells and lower the conversion efficiency.
To prevent this from happening you can give your solar panels a clean from time to time. You may also want to consider designing your system so that it sees minimal shading from trees or other objects.
You can see this guide on how to buy solar panels for your home for more info.
Temperature derating & degradation
There is a certain point where sunlight will actually turn into thermal energy (heat) and begin to negatively impact the solar cells.
Over time, the hotter the solar panel gets the less efficient it will be. Some solar panels can actually get to temperatures of 65°C degrees or more. This could impact the solar panels output by as much as 26%.
This is why solar panels are installed using racks; to allow for airflow to happen through the panels. It helps cool them down and maintain a good level of efficiency.
Which way your solar panels face
Another pretty obvious one. If your solar panels are facing towards the sun they will get a higher sunlight coverage. The more sunlight, the more energy can be converted.
If possible, you really want to face your solar panels towards the sun. For those who can’t it’s not the end of the world. You can add some extra panels to make up for any loss however it means your system will be less efficient and may cost more.
The job of the inverter is to convert the DC current in AC current so that it can be used to power your house.
Although technology is improving, inverters are still not 100% effective. You may even see a loss of up to 8% in energy conversion. The best inverters for energy conversion are sungrow and fronius.
Long cable runs
Small amounts of energy are always lost through cables. This is why short cable runs will give you more energy as there is less time and length that the energy can be lost. The longer the cable runs, the more energy will be lost.
It’s also important to use good, strong cables to prevent further energy loss. Luckily, we do have a lot of requirements to meet so most installers will be using industry standard equipment and cables.
How do you calculate solar panel efficiency?
We usually leave this up to the scientist in their labs to determine the efficiency of a solar panel. They can perform a series of accurate tests to work out how efficient the solar cell is converting energy at.
All tests are done based on a 25 degrees clear, sunny day. They will test the panel under common conditions of light exposure, panel orientation and panel temperature.
However, there are ways to find out the output and efficiency of your solar panels. It’s a bit long winded, but it will get you a fairly accurate rating.
You will need to multiply the amount of sunlight that hits the earth’s surface in your area by the area of your solar panel (measured in square meters). Once you have your answer you will need to divide it by the maximum wattage of your solar panel and times by 100. Here you should have your solar panel efficiency.
Does solar panel efficiency matter, or is it nonsense?
There are arguments for both sides of this. I’m going to run through both of the arguments and explain why they are important.
And yes, I am going to take a side and tell you why solar panel efficiency does NOT matter as much as you think.
Why people say it doesn’t matter…
The argument is that all solar panels will produce the same quality of electricity. Having a more efficient solar panels system won’t give you better energy, brighter lights or higher quality energy.
Homeowners don’t really need to have the most efficient solar panels on the market. Usually, solar panels with only 16-20% efficiency can be enough to significantly reduce your energy bill.
Yes, I agree that having the most efficient solar panel is cool but it’s actually quite unnecessary. It’s also more expensive. Unfortunately, solar cell technology is still young which means that the prices for the best are still really overpriced.
For systems with just 3-5% more efficient you will have to pay almost double in cost.
Is it really worth it?
For me, if I pay double I would at least expect it to be twice as good… Right?
Why people say it does matter…
On the other hand, a lot of people will tell you that solar panel efficiency is one of the most important factors you should consider when buying solar panels.
The argument is that with a higher efficiency solar panel you can generate more energy for less. It means that you will be able to see a quicker return on investment and more overall electricity.
Travis makes a good argument about why solar panel efficiency is important. He shows how a more expensive but higher efficiency system can give you more energy and faster ROIs.
It’s also good to point out that more efficient solar panels will allow you to fit more in a smaller space. This means you can utilise your roof and get more energy output.
To be honest, I wouldn’t worry about solar panel efficiency too much. I definitely wouldn’t make it one of my buying criteria. If you get a 6.6Kw system then that’s the amount of energy it’s going to produce regardless of the solar panel efficiency.
The 12 Most Efficient Solar Panels In 2020
Here are the 12 most efficient solar panels of 2020 as an easy to digest infographic!
And here are the 12 most efficient solar panels of 2020 as an comparison chart:
Hi Mo 4
Why is solar panel efficiency so low?
Well, there are a few reasons why.
Firstly, solar panels actually do have a maximum efficiency before they start to generate thermal energy, which is heat.
It’s around 60-85%, after this the solar panel will start to release heat and burn. This actually means we are limited in the amount of sunshine we can actually convert into energy.
Solar panels are fixed
Another reason is because most solar panels are fixed and do not follow the sun. As mentioned above, solar panel efficiency is determined by the amount of sunshine on the solar panel that is converted into energy.
Sometimes the position of the solar panel is not directly facing the sun, therefore the sunlight is ‘weaker’ will ultimately convert less. Panels that follow the sun will have a much higher efficiency rating.
Lastly, the materials that are used are really expensive and undeveloped. It costs a significant amount of money to research new materials that may work better. If it costs more to find new materials, then the price will flow down to the consumer making solar more expensive over all.
Solar efficiency costs a lot of money...
We have come really far in terms of price over the past few decades. Solar is becoming more and more affordable. New technology and more efficient solar panels may increase the price of solar, which may lose its popularity.
Now days, you can even generate oxygen with solar panels. New advanced technology breakthroughs are making progress in the right direction for a more stable future.
Either way, solar panels with around 20% efficiency will be able to significantly reduce homeowners energy bills. It means you can rest easy knowing that even with low efficiency, you are still saving money.
So there you have it, the most up to date information on the most efficient solar panels. Of course, it is always changing. As technology develops and companies grow they will invest in their products to improve efficiency.
Just a few months ago it was announced that Jinko had broken a record with the most efficient solar panel at 24.79%…
I will keep this list upto date, to make sure the information is relevant. However, I did hope that my readers may realise that efficiency is not everything. It’s something that you should probably consider if you have a large budget.
If you have a smaller budget, then don’t worry too much about it. It will be interesting to see where the future takes us with efficiency. Maybe we could get some technology that reaches up to 60-70% efficiency (without generating thermal energy)? Who knows…
Do you think that efficiency is the most important thing when buying a solar system? Let me know your thoughts. 🙂
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Lightning Solar & Eletrical