Solar panel peak efficiency. Solar Panels with the Lowest Temperature Coefficient

What Are the Most Efficient Solar Panels?

If you’re looking for the best solar panels, efficiency can be a good metric to consider. In this blog, we’ll explain what exactly solar panel efficiency means, and we’ll also share the brands with the top ten most efficient solar panels.

The efficiency of a solar panel is the percentage of the sun’s energy the panel converts to electricity.

For example, let’s say the sun shines the equivalent of 1 kilowatt (kW) or 1,000 watts on your solar panel. Your solar panel converts that energy into 200 watts of electricity that you can use to power your home or business. This panel would have an efficiency of 20%.

Most solar panels today are between 17% to 19% efficient. The least efficient panels will be around 15% efficient, and the highest are just shy of 23% efficiency.

The more efficient your solar panels, the more electricity your system will produce. In some cases, installing panels with higher efficiency means you can install fewer panels and still meet your electricity needs. This can be helpful with space concerns. However, it’s often the case that the more efficient the solar panel the more expensive they are as well. Typically, a higher quantity of less efficient panels will be cheaper than a smaller quantity of high efficient panels, even if the total system size is the same.

Why Aren’t Solar Panels 100% Efficient?

The most efficient solar panel comes in at 22.8%. That number can seem underwhelming. But the sun gives off such an immense amount of energy that even capturing a fraction of it can generate enough electricity to power many homes, businesses, and farms.

The efficiency of a solar panel is limited by the type of energy the sun produces. This energy falls across a large spectrum. Just like only a small fraction of this energy is visible to humans, present-day technology allows for only a portion of it to be converted into electricity with solar panels. Research and development teams at solar panel manufacturers are continuously working to harness a larger percentage of energy on that spectrum, which leads to increased efficiency of their panels.

If solar panels continue to get more efficient, you may wonder whether you’d be better off waiting until technology advances a bit more. But most people won’t be better off, as the small incremental gains in panel efficiency won’t make up for the months or years of free energy you’re missing out on.

The Ten Most Efficient Solar Panels

Here are the brands that offer the ten most efficient solar panels.

While efficiency can certainly be a valuable metric when selecting the solar panels for your system, it shouldn’t be the only thing you take a look at. A high-efficiency percentage isn’t the only indicator of a high-quality panel.

You should look at the duration of the product and performance warranties offered by the manufacturer. You should also take into account what size (60-cell vs. 72-cell) and what type (monocrystalline vs polycrystalline) of solar panel best suits your installation budget, available space, and aesthetic style.

In addition to installing the high-efficiency Q-Cell panels, we’re proud to install Axitec panels, which come in with efficiency ratings at 17.9%.

While not high enough to crack the top ten list, this brand creates high-quality, well-warrantied panels in a variety of sizes and types. Depending on the specifics of your system, you may be better off installing panels from this brands, even if that means a few additional panels.

Factors Affecting the Quality of Solar Panels

As the popularity of solar energy continues to rise, so does the number of solar panel brands. Although having a wide variety to choose from can be a good thing, it also complicates the selection process. To help with your search for the best solar panels within your budget, we stacked up the top solar panel manufacturers and brands against each other.

Efficiency

Solar panel efficiency is a measurement of how much sunlight a panel can transform into electricity. This means that if the sun shines for the same amount of time on two solar panels with different efficiency ratings, the more efficient solar panels produce more power than their less efficient counterparts.

Solar panel efficiencies range from a low 10% to a high 22%. Cheaper thin-film panels usually have the lowest efficiency rating, while most crystalline modules are rated at 14-15%. Of the two types of crystalline modules, monocrystalline solar panels are more efficient than polycrystalline ones. Outliers are those modules that use more modern technologies and can convert solar power into usable electricity at a higher than 22% efficiency.

Solar panels also have varying wattages or power ratings. The wattage indicates the amount of solar electricity they generate, ranging between 250-350 watts. Solar panels with higher wattages are generally more efficient, but they also cost more.

A solar panel with higher efficiency can produce more electricity than one with a lower efficiency rating. This is a factor to consider when you have limited roof space vis-a-vis your energy consumption.

Temperature Coefficient

Lab tests show that the temperature of solar panels generally runs between 15°C (59°F) and 35°C (95°F). At this range, the solar cells inside the modules perform at peak efficiency. As the panels heat up, solar panel efficiency drops, leading to a decrease in solar output.

Solar panel manufacturers rate how well their product handles heat or cold in the form of temperature coefficient. This refers to the percentage decrease or increase in the electricity produced by the system for every degree the temperature rises beyond 25°C, or for every degree it goes down below 25°C.

Solar panels usually experience a 0.05% drop in efficiency for every temperature rise above 25°C. It may not seem like much, but the power loss adds up, which lessens the savings you get from using solar energy.

A more efficient solar panel exhibits a lower reduction in efficiency when exposed to heat or cold, which boosts its performance in transforming sunlight into solar power.

Materials Warranty

The material warranty on a solar panel protects you against equipment breakdown resulting from manufacturing defects and environmental factors. Your PV power system has different components, such as batteries and inverters, and each has separate warranties.

If, for some reason, your panel stops producing electricity or its production falls way below the rated capacity, a materials warranty will ensure that the manufacturer will replace the module at no cost to you. Sometimes the warranty will even cover the shipping fee.

These warranties vary depending on equipment types and solar panel manufacturers, but they commonly cover 10-25 years. Examine the warranties offered by different companies to help you find the best solar panels for your budget.

In connection with the warranties provided by the solar panel manufacturer, you should also consider the bankability or reputation of the solar company. Years of warranty won’t do you any good if the solar company won’t be around to honor their warranties.

The materials warranty can also be a gauge in determining the durability of solar panels. Logic dictates that the more extended the warranty provided by solar panel manufacturers, the higher their confidence in their product.

Performance Warranty

Solar panels naturally degrade over time. This degradation means that they start to produce less electricity over the years, sometimes losing between 10-30% of their original production. The performance warranties guarantees that your PV panel’s generating capacity won’t fall below a certain level within the warranty period.

A typical guarantee among manufacturers is that the panels will generate electricity at 80%-90% up to the end of their 25-year lifespan.

The level of coverage, as well as the duration of the warranty, vary from each installer.

Cost

The average cost of a solar panel system continues to fall. But even as the price of a solar system becomes more affordable, evaluating the costs in relation to the durability, efficiency, and performance of the different modules should be one of your considerations.

Solar panels cost around 5000.38 to 3.14 per watt. That means that the price for a 10 kilowatt PV system in the country may range between 17,612 to 23,236 after the federal investment tax credit (ITC).

Solar Panels with the Highest Efficiency

Highly efficient solar panels produce more solar energy per square meter compared to PV modules with average efficiencies. That makes them ideal for homes with limited installation space for their solar panel system. By using the most efficient solar panels, you can reduce the number of modules you’ll need for your energy system.

Based on efficiency alone, the companies that make the best solar panels are:

• Sunpower (22.8% efficiency)
• LG (22%)
• REC Group (21.7%)
• China Sunergy or CSUN (21.2%) and Panasonic (21.2%)
• JA Solar (21%)

Solar Panels with the Best Warranty Services

The warranties covering the solar panels can help reduce out-of- expenses when your solar panel system experiences some problems.

A ten-year warranty for a budget panel is pretty good. However, some of the best solar manufacturers offer warranties that last 25 years or longer. Based on the warranty coverage, here are what we deem the best solar panels made by the world’s leading manufacturers.

Panasonic

A Japanese corporation, Panasonic, is the manufacturer of the innovative heterojunction solar panel. This type of module combines a crystalline silicon cell and amorphous “thin-film” silicon. Using the two technologies allows the solar panel to capture more energy than using either technology alone.

Solar panel warranty: 25 years

Power/performance warranty: 25 years. The maximum degradation per year is 0.25%, with a guaranteed output of 90.76% after 25 years

SunPower

This is an American company that manufactures a wide range of solar equipment. SunPower solar panels include the budget-friendly E-series, the high-end X-series, and the A-series, which are solar panels that come equipped with an integrated microinverter.

Solar panel warranty: 25 years

Power warranty: 25 years. With a maximum of 0.25% degradation per year and a guaranteed 92% output after 25 years.

LG

This South Korean company manufactures all sorts of appliances and electronics. Among their solar products are the LG bifacial solar panels that generate solar energy from both sides of the module.

Solar panel warranty: 25 years

Power warranty: 25 years. The panels are guaranteed not to exceed 0.30-0.35% degradation per year. Their output after 25 years is guaranteed to remain at a range of 89.60-90.8%.

Silfab

This Canadian solar panel company specializes in monocrystalline panels, but they also manufacture polycrystalline solar panels.

Solar panel warranty: 25 years

Power warranty: 30 years. Their panels carry a guaranteed maximum degradation of 0.5% per year for monocrystalline and 0.7% per year for polycrystalline. The warrantied output of their mono panels is 82.6% and 79.5% for polycrystalline modules at the end of 30 years.

Solaria

Although the company is US-based, it also manufactures solar panels in South Korea. Their solar panel line includes all-black AC and DC modules that come with integrated microinverters.

Solar panel warranty: 25 years

Power warranty: 25 years. 0.5% is the maximum degradation per year, and the solar panels come with a guaranteed 86% output after 25 years.

Solar Panels with the Most Reasonable Cost

The price of a PV installation is one of the barriers to the adoption of solar energy. However, affordable solar panels make it easier for those who want to go solar to switch to this renewable energy.

The best solar panels when it comes to cost are:

• ReneSola JC255M-24/Bb: 173.40 per panel,
  

  Solar Panels with Special Features

  As solar panel technology advances, we see more and better features in the newer solar panels on the market. The world’s leading solar panel manufacturers seek to address various issues associated with solar panel installations by producing more efficient modules, panels with low degradation rates, those with greater durability, and so on.

  So now we see high wattage and high-efficiency solar panels that can withstand strong winds. Some PV modules on the market today can also generate energy on both sides of the module. There are clear solar panels as well as frameless and flexible ones. We expect the innovations to continue as we see more residential solar panels blossom atop more homes in America.

  The best solar panels with added special features include the following:

• SunPower A Series: These are the world’s first 400-watt panels, and their efficiency rating goes over the standard 22%.
• Panasonic EverVolt: This solar panel line boasts of low degradation rates and a guaranteed power output of at least 92% after 25 years, one of the highest among the panels on the market.
• REC Alpha Pure Series: Using gapless cell technology makes this line one of the most efficient solar panels on the market. By eliminating gaps in the cell string, the PV modules can accommodate more solar cells, which boosts their efficiency.
• LG Solar Panels Neon Series: These solar panels utilize double-sided cell technology, which allows the modules to capture the sun’s power on both sides. This ability can produce up to 35% more energy.
• Hanwha Q CELLS Peak Duo: Strong winds and heavy snowfall can damage solar panels. The Hanwha Q CELLS Peak Duo can withstand wind loads of up to 2400 Pascals, which is similar to 140 mph winds and snow loads of up to 5400 Pascals.

.68 per watt

A short history of solar cell technology

Humans have been tapping the power of the sun for centuries. Magnifying glasses were used to concentrate the sun’s rays to ignite fires in the 7th century B.C., and architects throughout history have built structures with an eye toward the sky to capture as much radiant heat as possible. But it wasn’t until the 1800s when the PV revolution really kicked into high gear. Here are some highlights:

• 1839: Edmund Becquerel discovered the photovoltaic effect in France when he noticed the voltage between two metal electrodes in an electrically-conductive liquid increased when exposed to sunlight.
• 1873: Willoughby Smith discovered that the element Selenium has photoconductive properties.
• 1876:William Grylls Adams and Richard Evans Day created a selenium solar cell that produced electricity when exposed to light, proving that solid matter is capable of transforming light into electricity (less than 1% efficient).
• 1932: The photovoltaic effect of cadmium sulfide was discovered by Audobert and Stora.
• 1954: Bell Labs developed the first silicon photovoltaic cell capable of producing usable electricity, with an initial solar panel efficiency rate of 4%.
• 1958: Hoffman Electronics created PV cells with 9% efficiency.
• 1959: Hoffman Electronics followed up with 10% efficient cells.
• 1960: Solar panel efficiency hit 14% by Hoffman Electronics.
• 1985: A 20% efficiency level was reached for silicon solar cells.
• 1994: The National Renewable Energy Laboratory (NREL) created a solar cell that exceeded 30% conversion efficiency.
• 1999: Spectorlab, Inc. and NREL developed a solar cell that was 32.3% efficient. (Three layers of photovoltaic material were combined into a single solar cell to achieve this level.)
• 2012: Solar Frontier achieved 17.8% efficiency on thin-film PV.
• 2015:SunPower recorded 22.8% efficiency for high-rate production commercial photovoltaic modules.
• 2016: NREL and the Swiss Center for Electronics and Microtechnology (CSEM) recorded 29.8% efficiency on a lab cell.
• 2016: SunPower broke their previous world record for the highest-efficiency (24.1%) commercial solar panel using silicon cells.
• 2019: EnergySage ranks SunPower #1 among the top 5 companies who produce the most efficient solar panels.

The major take-away from this quick skip through time is that the history of solar panel efficiency shows impressive advances at first, but is now running up against the barriers of physics. Higher efficiencies require technologies that are harder to produce at scale at an agreeable cost. In other words, don’t expect any major jumps in efficiency for commercially-available solar panels any time soon.

In fact, depending on which physicist you talk to, there is also a very real theoretical limit to how much efficiency is possible for commercially-viable modules. Most authorities put that upper cap at about 30%. For some perspective, the average commercial solar panels manufactured today (with a few exceptions) hit a range of 17% to 20%.

Bottom line: While the future of solar technology is bright, advances will likely be modest for high-efficiency commercial solar panels.

But records are made to be broken, right?

Creating high-efficiency commercial solar panels that break records is a worthy goal. However, when you see claims of a new efficiency milestone being reached, be warned the results are often confined to the laboratory with no practical real-world applications on the horizon. The maximum efficiency number noted earlier is for something called “single junction cells.” These are your standard, mass-produced (and relatively-inexpensive) solar cells. When you see efficiency numbers climbing into the high 20s or beyond, be sure to read carefully. It usually means there’s some fancy tech going on that won’t likely hit the commercial market any time soon (if ever).

There are some other processes that can produce greater solar efficiency rates that do offer real commercial potential. For example, layers of different materials can be sandwiched into a single cell to capture different light spectrums, resulting in greater efficiency (more light is captured). Another approach uses lenses to concentrate sunlight onto small, highly-efficient cells (more sunlight goes into the cell, so more energy is produced). These applications can vastly improve solar panel efficiency, but likely at a considerably higher cost. The added expense may be worth it if you’re trying to power an orbiting satellite—where size, weight and amount of power generated are key. For commercial solar power systems, however, they simply aren’t practical.

Comparing efficiency ratings

Now that you have a better understanding of what you’re looking at when you see a solar panel efficiency rating, here are a few other things to think about:

• Not all solar cells are made the same. Seems obvious, but it’s worth noting. Take the industry-dominant silicon solar cell. Is it mono- or polycrystalline silicon? Monocrystalline silicon is purer and produces a more efficient solar panel; however, it is also more expensive to produce. For an interesting overview of the pros and cons of different types of solar panels, check out this article from Energy Informative.
• Not all solar equipment providers readily offer up the efficiency of the panels they sell. It could be the company doesn’t want to provide the information if it doesn’t help sales. Or, they could actually believe that efficiency is not important. Having this information is required by law, so don’t hesitate to ask.

So how important are efficiency ratings?

Are efficiency ratings important if the differences are within a few percentage points? That depends who you ask.

• Some argue that as solar cell costs go down and efficiency improves, it becomes less important because mounting hardware, inverters and other components of a solar power system have a bigger impact on the overall install.
• Others counter that solar panel efficiency is important because more efficient solar panels can produce more power in the same amount of space. This is great for constrained areas or if you just want to get maximum output. It could also mean fewer solar modules to generate the energy you need, which can lead to lower installation costs and less preventative maintenance down the line.

When you realize that commercial solar is a long-term commitment, it would be short-sighted to FOCUS solely on upfront costs. Considering solar panel efficiency ratings, as well as other aspects of your investment that could lead to the most savings over the life of your system, is not only important—it’s the Smart thing to do

Time of Year

The amount of sunlight that reaches your panels is also affected by seasonal changes, or variation in daylight hours throughout the year. In California from late spring through the summer months there are more daylight hours than any other time period. This makes these months ideal for maximizing your system’s output potential without having to invest in additional hardware or equipment.

During winter months, daylight hours are fewer than those of warmer seasons. This can cause a decrease in solar power outputs. However, this doesn’t necessarily mean that your system won’t be able to produce enough energy during these times. In fact, the way you position your solar panel array can make all the difference. By positioning them so they receive direct sunlight for as much of the day as possible, you can still maximize their output potential even when daylight hours are fewer than usual. It is also important to consider weather conditions such as Cloud cover and rain when positioning your panels as well.

Ideally speaking, it would be best to install your solar array where it will receive direct sunlight at all times of year, not just during summer months when there are more daylight hours available.

Identifying Potential Obstacles

Once you have identified how much sun exposure your area receives at certain times of year, it’s time to look for potential obstacles that could impede the performance of your system. These obstacles can come in many forms—from buildings and trees blocking out the sun’s rays to nearby power lines interfering with signal transmission.

It’s important to take all these potential obstacles into careful consideration before deciding on a location for your array. Of course, if any obstacle cannot be avoided or removed, then other solutions such as using specialized mounting systems or changing the angle and orientation of panels may need to be considered instead.

When evaluating any potential obstacle that could affect your solar panel system’s performance, it is important to think outside the box when it comes to finding ways around them. For example, if nearby trees are blocking out most of the sunlight during certain months or times of day, trimming back branches or planting taller trees may be an option worth considering in order to increase access to direct sunlight without needing additional mounting hardware or adjusting panel orientation angles.

The time of day, the season, and potential obstacles are not the only things that impact your peak solar hours. Another big element that can change the output is the age and maintenance of your solar panels.

Age and Maintenance of the Panel

Solar panel technology has come a long way since its inception over 100 years ago! Today’s modern photovoltaic cells have higher efficiency ratings and longer lifespans than ever before which means that older models may not perform as well as newer ones do due to wear-and-tear over time caused by exposure to ultraviolet rays as well as other atmospheric conditions like temperature fluctuations or precipitation levels.

If you choose not to clean and maintain your system regularly then dust buildup can reduce its overall efficiency which is why we recommend scheduling regular maintenance checks with a qualified technician for optimal performance. Doing so will allow any issues to be identified quickly and addressed in a timely manner. This can also help prevent more serious problems from arising down the line.

In addition, it’s important to check your system often for signs of wear-and-tear due to exposure to ultraviolet rays as well as other atmospheric conditions like temperature fluctuations or precipitation levels. If any damage is found during the inspection, it’s best to get it taken care of right away in order to avoid any further issues with your system.

Conclusion

Solar panels are most efficient when they receive direct sunlight, which means that the time of day and year are major factors in determining a solar panel’s output. Additionally, the obstacles that block the light and the age and maintenance of your panels also play a role in their efficiency.

By understanding these key elements, you can make sure that your solar panels are working at their best and generating the most power possible. If you have any questions about how to get the most out of your solar energy investment, our team of experts is here to help. Give us a call today to learn more about how we can help you maximize the performance of your solar panels.

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