Who makes the world’s most efficient residential solar panels? The panels listed here have earned the right to be considered when homeowners are looking for a system to provide the best savings over the years. Remember that solar technology is moving quickly and striving for higher efficiency with each new panel created, so manufacturers regularly discontinue solar panels and release new,
more efficient panels to take their place. This chart will help get you started
understanding available solar panel efficiencies from a variety
|1||SunPower||USA||X21-345||Mono||21.5%||240 WP||25 YEARS|
|2||JA Solar||China||JAC M6PA-4||Mono||20.9%||290 WP||10 YEARS|
|3||Sanyo||Japan||HIT Double 195||Mono||20.5%||195 WP||20 YEARS|
|4||SunPower||USA||327-320||Mono||20.4%||327 WP||25 YEARS|
|5||SunPower||USA||245-235||Mono||20.1%||245 WP||25 YEARS|
|6||Schosser Systems Photovoltaik||China||SSP180-260||Mono||20%||260 WP||2 YEARS|
|7||SunPower||USA||E19-320||Mono||19.8%||320 WP||25 YEARS|
|8||AUO||Taiwan||Sun Forte PM318B00||Mono||19.5%||318 WP||5 YEARS|
|9||Sanyo||Japan||VBHN245SJ25||Mono||19.4%||245 WP||20 YEARS|
|10||SunEdison||USA||R355BzC||Mono||18.2%||355 WP||10 YEARS|
|11||SunTech||Japan||STP285S-20/Wem||Mono||17.5%||285 WP||10 YEARS|
|12||Yingli Green Energy||China||YL225C-24b||Mono||17.1%||225 WP||10 YEARS|
|13||Phono Solar||China||PS330M-24/T||Mono||17%||330 WP||10 YEARS|
|14||JA Solar||China||JAP6 60- 275/4BB/RE||Poly||16.8%||275 WP||10 YEARS|
|15||Canadian Solar||China||275 M||Mono||16.8%||275 WP||10 YEARS|
|16||REC||Norway||REC275TP||Poly||16.7%||275 WP||10 YEARS|
|17||JA Solar||China||JAM6 (R) 72-325||Mono||16.7%||325 WP||10 YEARS|
|18||Jinko Solar||China||JKMS320P||Poly||16.5%||320 WP||10 YEARS|
|19||JA Solar||China||JAM6 48-215/SI||Mono||16.4%||215 WP||10 YEARS|
|20||Trina Solar||China||315||Poly||16.2%||315 WP||10 YEARS|
|21||JA Solar||China||JAM6(TG)-60-265/SI||Multi||16.2%||260 WP||10 YEARS|
|22||Yingli Green Energy||China||YL205P-23b||Poly||15.8%||205 WP||10 YEARS|
|23||Kyocera||Japan||KU255-6BCA||Poly||15.5%||255 WP||10 YEARS|
|24||Sharp||Japan||ND-F4Q300||Poly||15.3%||300 WP||10 YEARS|
|25||Yingli Green Energy||China||YL 235 P-29b||Poly||14.4%||235 WP||10 YEARS|
Understanding Solar Panel Efficiency
Solar panel efficiency can make an enormous difference in the savings realized on monthly utility bills over the long run. The efficiency of solar panels is based on the ability to convert sunlight into electricity. If the same amount of sunlight shines for the same duration on two different panels, the one with the highest efficiency will produce the most electricity.
Though solar panel efficiency is rising quickly, some companies still do claim efficiency numbers that are garnered only under strictly controlled test conditions – which is not what homeowners get when they install a system. In the real world, efficiency depends upon the type and brand of solar panel being used, as well as on-site considerations. Getting the maximum efficiency from your solar panel depends on several factors:
- Irradiance (the amount of sunlight)
- Wind speed and temperature
- Angle of the panel
- Panel direction
What can homeowners reasonably expect?
“On the high side at around 22.1 percent and on the low about 14 percent,” MacLeod said. “I almost never see a panel produce to its full efficiency rating in field conditions. There are usually as much as 20 percent in losses.”
To ensure solar panels are top-notch in terms of efficiency, it’s time to do some homework. This guide is designed to help homeowners understand how efficiency works, how to choose the best solar panels for the job and learn how to compare solar panels to find the ones that work best for a particular environment.
Solar Panel vs. Solar Cell Efficiency
Solar panels are only as efficient as the solar cells inside them – but why doesn’t the higher solar cell efficiency translate into higher solar panel efficiency? One of the top reasons is simply how those cells are used in the panel space.
“Look at the cell layout on the panel face,” MacLeod said. “Some manufacturers make more efficient use of the available area on the front and back of the panel. More cells, less cells, types of cells – all determine efficiency.”
Crystalline silicon PV cells have laboratory energy conversion efficiencies as high as 25 percent for single-crystal cells and 20.4 percent for multicrystalline cells. However, industrially produced solar modules currently achieve efficiencies ranging from 18–24 percent.
Manufacturers are getting smarter about configuring solar panels, just as the industry is getting better about producing higher-efficiency cells for those panels.
“Eight years ago we were using panels that were 12 percent efficient, now we are up to 22 percent. Pretty good so far,” MacLeod said. “All the manufacturers are competing against each other for the efficiency prize.”
Manufacturers to watch are SunPower, LG, Solar City, Panasonic along with many others.
Another issue with higher-efficiency solar panels is the prohibitive cost.
“There are cells out there that are as high as 44.5 percent efficient but will take a lot of time before they come to market,” MacLeod said. “Pathfinder on Mars used cells that were 44 percent efficient but cost over a million dollars.”
Obviously there is huge room for growth with solar efficiency, but the world of solar changes very quickly, and companies are already tackling the efficiency issues. MacLeod said he believes that the near future will show big changes in wattage, battery storage technology and the makeup of the panels themselves.
“Efficiency will continue to increase as Multi Layered Cells and Gallium Arsenide cells enter the market,” he said. “Panel wattage is on the increase as well. Ten years ago it was 185 watt panels, now its 300s, 315s, 345s, 360s and on.”
Look for dramatic efficiency increases in the next
five to 10 years.
What Affects Solar Panel Efficiency?
Though the technology that makes up the panel itself has a strong impact on efficiency, the site where the solar panels are installed also has a hand in the amount of power created. In some areas of the country, solar panels will be more efficient simply because of a more conducive environment. But efficiency can vary dramatically from one neighborhood to the next or even from one home to another on the same street, based on site considerations. The following are the biggest factors in solar efficiency outside of the panel itself.
Obviously, the amount of sunlight hitting a solar panel will
determine how much of that potential energy is absorbed.
But shade does more damage than you might think:
the efficiency of the entire solar array can be compromised
by a little bit of shade on one solar panel, as it has the potential to
‘shut down’ or slow the efficiency of all connected panels. The best
possible site is a roof with no shade at all.
While it might seem that the hotter the area, the better the efficiency, that’s not true. Solar panels don’t necessarily like heat, which is why they are installed to allow a few inches of room between the roof and the panel – it allows for airflow that helps cool them down. Though some solar panels are designed to handle hotter temperatures, most actually experience a decrease in efficiency when exposed to high temps.Orientation
A roof with a true south slope is optimal for efficiency; however, others can work well. Though a direct east or west orientation will produce about 20 percent less power than a true south facing, even that can be improved with the right tilt of the panels.Roof tilt
The angle at which the sunlight hits the panel can drive efficiency up or down. When the sun hits the panels at a shallow angle, the light reflects away, which means the panels cannot collect as much as they would if facing the sun directly. Some roofs have a pitch that means the sun never quite hits the panels directly; this might be remedied by installing the panels in such a way that compensates for the tilt of the roof. This requires a strong site survey and excellent design to achieve maximum panel efficiency.
Solar Panel Tracking Systems
With so many issues concerning the tilt and orientation of solar panels, some homeowners might be curious about tracking systems. These systems do just what it sounds like: they track the path of the sun by moving the solar panels to achieve the best solar coverage possible.
follow the sun from morning to evening; dual-axis trackers also track from morning to evening, but take into account seasonal changes as well. Dual axis trackers obviously have more opportunity to capture energy; they can provide up to 40 percent more harvesting power than fixed arrays.
rely on the heat of the sun to warm liquid in canisters on the side of the array; the liquid in the exposed canister turns into a gas, which pushes excess liquid into the shaded canister, thus tilting the array throughout the day. Active trackers rely on photosensors or software to determine the route of the sun and uses hardware to move the array accordingly.
It sounds like a good idea: it would allow homeowners to capture as much of the sun’s rays as possible. But MacLeod has some misgivings.
“Trackers are mostly used for ground mounted systems,” he said. “They are ideal for areas like New Mexico and Nevada where the irradiance factors are the highest. They also have motors and moving parts that can fail in extreme environmental conditions of the northeast. As the cost comes down on trackers, then I might give more positive consideration to using them.”
As solar panels become more affordable, the costs of trackers will continue to drop in order to compete the in the market. But besides the cost, there are a few other downsides to consider.
Solar trackers might be very heavy, depending upon the size of the array, which doesn’t make them a viable option for many roof-mounted systems.
They are made of moving parts, which can lead to more maintenance requirements and opportunities for the system breaking down.
The warranty might be troublesome as well: companies routinely offer anywhere from two to 10 years under warranty, while inverter and panel warranties typically start at 10 years and go up to 25 years or more.