If you ask a farmer about the biggest vegetable they have ever grown, they will excitedly tell you about the 2.5 kg potato that looked like a Teddy Bear. But ask a solar expert about the largest panel they have seen or used, and they will just shrug. The reason for this is not that gigantic solar panels can’t be made - it is simply because somewhat standardization of solar panel sizing helps with the logistics and installation.
But how big are solar panels exactly? Let us find out.
What is a Typical Solar Panel’s Size?
A typical solar panel is about 1 metre wide and can be 1.6 m to 2 m long, while the thickness usually ranges between 3 to 4 cm. These dimensions may vary with the manufacturer, but will have more or less the same numbers.
You may have noticed that the length varies quite a bit (1.6-2m), compared to the width and thickness. The reason for this is the two types of available solar panels - 60 and 72-cell. Each solar panel is made of an array of solar cells, each about 15 cm x 15 cm. A 60-cell panel has 10 rows of 6 cells each (10 x 6), while a 72-cell panel has 12 rows of 6 cells each (12 x 6). Most 60-cell panels will be around 1.6 m long, while most 72-cell panels will be around 2 m long.
What is a Typical Solar Panel’s Weight?
A typical 60-cell solar panel will weigh around 19 kg. A 72-cell panel, on the other hand, may weigh around 21 kg. Depending on the manufacturer and the materials used, these numbers can be higher or lower, but usually do not vary by more than 1 kg.
Interestingly, the solar cells in a panel are the lightest component of the panel, and make less than 5% of the solar module’s weight. The majority of a solar panel’s weight comes from the front glass - a large, rectangular piece of glass with anti-reflective layer. Then comes the aluminium frame and back sheet.
Solar Panel Sizes and Wattages
When two people from the solar industry are speaking to each other and they use the word “big” to describe a solar panel, they are likely referring to its power rating, and not its physical size. To understand if a solar panel is any good, knowing its physical size is hardly useful. What matters more is its power rating, given in watts.
While it is true that the physical size and watts will be proportional to each other, high-efficiency panels can generate more power per unit surface area. For example, a 60-cell polycrystalline solar panel may generate 250W while a 60-cell monocrystalline solar panel can generate over 300 W for the same physical size. In other words, “efficiency”, a.k.a. power produced per unit area matters more than the physical dimensions of a solar panel.
Does a Solar Panel’s Size Matter?
We just discussed that the efficiency of a solar module matters more than just its dimensions. But if we put the efficiency aspect aside for a while, how does the physical size impact the solar panel’s use?
Theoretically, it is possible to manufacture a solar panel of any size. You can build a single panel that is the size of your roof, and then have just one panel generating all your power. It might be a “cool” idea, but it is not a smart one. If a panel is too long, it becomes difficult for the panel to support its own weight, and it is susceptible to bending and breaking near the centre. Excessively large solar panels can also be difficult to manufacture, transport and install.
Overall, the industry has found 60-cell and 72-cell panels to be a good balance of dimensions, weight, and power output. There are, of course, half-cell solar panels where the cells are cut in half, so technically they become 144-cell panels, but since they are made from originally 72 full cells, they are similar to 72-cell panels when it comes to just the physical sizing.
Sizes and Weights of Solar Panels in New Zealand
Solar power companies in New Zealand offer a variety of solar panels. And though there are a dozen sizes available, the most commonly used panels are usually 60 or 72 cell ones - ranging from 300 to 500 W. Here is a table of sizes and weights for some of the most popular solar modules available in the country.
|SunPower Maxeon 5 AC||410 W||1835 x 1017 x 40 mm||21.1 kg|
|Trina Solar Vertex S||400 W||1754 × 1096 × 30 mm||21 kg|
|Canadian Solar CS3W-415W||415 W||2108 x 1048 x 40 mm||24.9 kg|
|Jinko Tiger Mono-facial||360 W||1692 × 1029 × 30 mm||19.3 kg|
|JA Solar JAM60S10-340W/MR||340 W||1689 × 996 × 35 mm||18.7 kg|
Solar Panel System Dimensions
Once we have answered the question of what the size and weight of a solar panel is, the next logical question is “how big is a typical solar system?” Usually, a 3 to 6 kW system fits the needs of most kiwis. While a 6 kW system will offset almost all of your power consumption, a 3 kW system might also make a good option to reduce your monthly bills.
Considering 400 W panels, you will need about 15 panels to generate about 6 kW of power, or about 8 panels to generate 3 kW of power. Considering the typical dimensions of 2 x 1.6 m for a 400 W panel, a 6 KW system may take up a roof area of 2 x 1.6 x 15 = 48 m2 , and a 3 kW system may take up about 25 m2. However, considering spaces between panels and some margins for wiring, racking etc., installers generally use the thumb-rule of 9 m2 per kW of solar installed.
Solar Panel Sizes and Efficiency
You may have seen the historic image from the 1950’s where four people are loading a 1 megabyte IBM hard drive into a truck, placed against the image of a modern 1 terabyte SD card the size of a thumbnail.
Although not that dramatically, solar panels have also consistently become more and more efficient. Just a decade ago, a panel efficiency of 18% was considered excellent. Today, 18% is the lower end of panel efficiencies, as most high-quality commercial panels boast efficiencies around 21-22%, while some lab models have also crossed the holy 25% mark.
Consequently, this means solar panels pack more power-generating ability in the same space. This means either the panels can get smaller, or remain the same physical size and offer more power. As it seems logical, manufacturers went with the latter option. A decade ago, a 200 W panel was considered “large”, but today, 400+ W panels are becoming more and more common.
We don’t know how solar panels will look in the future. But we know one thing for sure - solar panels have never been more powerful and more efficient, and this is definitely the best time to go solar!