Solar Panel Efficiency Over Time

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Solar energy starts with the sun. 

Also known as “PV panels,” solar panels take in light from the sun, which is comprised of energy particles called “photons,” and convert it into usable electricity that can power all kinds of appliances and functions. 

You can use solar panels for a broad range of applications, such as remote sensing, telecommunications equipment, power systems for cabins, and, of course, to generate electricity for solar electric systems used in houses and commercial buildings. 

In this guide, we will review the history, technology, benefits, and long-term efficiency of using solar panels. 

A History of Solar Panels

Solar energy’s history dates back more than 100 years. 

In its early days, people initially used solar energy to produce steam that they would then use to drive machinery. However, it wasn’t until Edmond Becquerel discovered the “photovoltaic effect,” named such for its ability to convert sunlight into solar electric energy, that allowed the technology to take off. 

This discovery later led to the invention of the first genuine solar cell in 1893 by Charles Fritts; he formed this cell by coating selenium sheets with thin gold layers. This new development would eventually lead to the device we currently know as a solar panel. 

In 1941, Bell Laboratories’ inventor Russel Ohl patented the first silicon solar cell. His invention led to Bell Laboratories’ production of the first solar panel in 1954. The first solar panels found use in space satellites, but most people’s first exposure to the technology was embedded in their calculators from the 1970s. 

A History of Efficiency

The earliest silicon solar panel cells were not very efficient. Additionally, running them was more often expensive than not. Fortunately, efficiency has gone up over time as prices have gone down. 

In 1955, Hoffman Electronics introduced photovoltaic products with an energy cost of $1,785 per watt at just 2% efficiency. Two years later, the same company introduced 8% efficient cells, followed by 9% cells in 1958 and 10% cells in 1959. The following year, efficiency skyrocketed to 14%.

In 1985, Australian researchers at the University of New South Wales constructed a solar cell with more than 20% efficiency. In the 21st century, efficiency continues to increase with no signs of stopping. For that matter, solar energy costs keep decreasing.

Today, complete solar panel systems power a wide range of applications. Of course, they still power calculators, but they also power entire homes and commercial buildings, such as Google’s headquarters.

How Solar Panels Work

Solar panels are designed to collect clean, renewable energy by absorbing sunlight and converting its photons into electricity. Homeowners and property owners can use this energy to provide power for electrical loads. 

The Photovoltaic Effect

Manufacturers put together several individual solar cells to develop solar panels; each of these cells is made with layers of boron to provide a positive charge, phosphorous to give a negative charge, and silicon to provide photoconductivity. The panels absorb the photons and initiate an electric current in doing so. 

As a result, the energy produced from the photons striking the solar panel’s surface allows the electrons to come out of their atomic orbits, ending up in an electric field. The solar cells generate this field and then pull the free electrons into a directional current. This whole process is called the Photovoltaic Effect. 

Efficiency of Solar Panels

An average home has more than enough surface space on the roof to store the number of solar panels needed to generate enough free energy to supply all of the homeowner’s needs. The excess electricity the panels generate goes onto the primary power grid, which means your electricity use pays for itself at night. 

In a well-balanced grid, a solar array spends the day absorbing the sun and generating power that the house uses during the night. Net-metering programs allow people who own solar generators to get paid if they generate more electricity with their systems than they need to power their homes. 

You will need a charge controller, battery bank, and likely an inverter to put together a solar system in an off-grid application. The array takes direct current (DC) energy and passes it through the charge controller to store it in the battery bank. Then the system draws the power from the bank to the inverter, which converts the DC energy into alternating current (AC) electricity suitable for non-DC applications, such as powering a home. 

Solar panel arrays can thus use inverters to meet demanding electrical load needs. The AC powers residential and commercial needs, cottages, remote cabins, recreational vehicles, remote traffic controls, boats, oil flow monitoring, telecommunications equipment, and more. 

Benefits of Solar Panels

Everyone can benefit from the practicality of solar panels in producing electricity. 

The most obvious benefit is the off-the-grid living opportunity. Living off-grid means living somewhere that a city’s main electric utility doesn’t service, such as a remote home or cabin. Instead of having to pay expensive fees to have cabling and electric utility poles installed, those living off the grid can use a solar electric system to provide power for 30 years or longer with proper maintenance.

Not only do solar panels make it possible for someone to live off-grid, but they also provide a clean and renewable source of energy; many consider this benefit to be the greatest one possible from using solar power. In addition, with the imminent arrival of permanent global climate change, it’s become clear that we must all do whatever we can to alleviate the pressure of greenhouse gas emissions on our atmosphere. 

Solar panels require little maintenance and have no moving parts; manufacturers build these rugged devices to last for decades with proper care.

Finally, one last benefit of using solar panels is the fact that any electricity they produce after paying for its initial cost covers the rest of the grid’s lifespan. As we’ve mentioned, a properly-maintained solar grid can last 20 years or longer depending on the quality, which means you can reap the benefits effectively for free for that entire time. 

For those who install grid-tie solar power systems, the benefit begins when you turn on the devices for the first time. In other words, this kind of system could eliminate your monthly electric bills or even generate additional income for yourself; if you use less power than you produce with your solar electric system, you can sell that excess power back to the utility company.

There are several other benefits of potential applications for relying on solar panels to generate electricity for your personal needs. Working with Impact Energy to install your grid will give you a broad knowledge of how convenient and versatile solar power can be. 

How Long Does Solar Last?

Although solar energy can save you substantial amounts of money in the long run, benefitting takes a long-term commitment. Additionally, the upfront cost can be expensive, but the investment more than pays for itself through the years in terms of monthly energy savings and annual tax incentives. 

Depending on the manufacturer, most solar panels usually carry a 25-year warranty, so it’s reasonable to expect that your solar panels will survive that long. However, in reality, studies show that panels keep operating at a reduced efficiency even after the warranty ends. 

Standard Solar Panel Warranties

Most solar panel warranties last 25 years. During this period, a solar panel manufacturer guarantees that its products continue to operate at peak efficiency or close to it. Most panels are guaranteed to perform at an at least 80% efficiency rating for the duration of the coverage. For example, a 300-wat panel should still produce 240 watts after 25 years of use. 

Some manufacturers may offer different values, such as 85% efficiency or a 30-year warranty on its panels. However, these companies are the outliers; the industry standard is to expect 80% efficiency at 25 years. 

Solar panels may also come with an additional craft warranty so policyholders can get manufacturing defects, such as a broken frame or faulty junction box, repaired. These warranties are typically shorter at 10 years, but some companies may offer longer terms. 

How Long Do Solar Panels Really Last?

Once the 25 years are up, your solar panels will keep working. So even though their efficiency has gone down to 80%, there is no real reason to replace solar panels that are still working. 

Most solar panels still produce energy long after the end of their warranty. According to a National Renewable Energy Laboratory study conducted in 2012, the average solar panel degradation rate is just 0.8% each year. Likewise, 78% of tested systems experienced a degradation rate of under 1% per year; that means that four out of five solar panels still operate above 75% after 25 years of use. 

Efficiency In Terms of ROI

If your primary concern is a positive return on investment (ROI), solar panel means good news. 

We cannot guarantee that every solar panel will outlive its warranty; after all, the point of a warranty is to cover its sudden failure. However, in reality, most panels continue to produce at a reduced efficiency for years after the end of the coverage. Solar panels tend to be highly durable and reliable without any moving parts.

If your solar panels continue to produce energy long after it pays off the system, your ROI will continue to stretch far beyond your initial estimates. 

Extending the Life of Solar Panels

If you want to make the most out of your investment, it’s vital to perform proper maintenance to ensure your solar panels last as long as possible. 

Because they have no moving parts, the panels are probably the most resilient part of your solar energy system. However, you still need to maintain and replace batteries and inverters to ensure the systems stay up and running. Inverters tend to last fewer years than solar panels, and you will need to replace them no matter what kind of system you install. Additionally, if you install a system off-grid, your battery replacement costs will add a few more dollars over the years. 

The most intelligent way to protect your solar investment is to inspect it as soon as it’s installed. First, check the racking to ensure the wiring and the panels are secure; the biggest threat to a solar panel’s life is physical damage or suffering electrical failure due to an improper installation. 

Replace Inverters Every Decade

Most manufacturers guarantee their grid-tie inverters for 10 years, allowing homeowners to upgrade to 25-year warranties instead.

Considering the hefty investment required to install a solar energy system, it’s wise to opt for a warranty extension for an inverter. After all, it’s safe to assume that you’ll need to replace it at least once or twice before the warranty on the panels ends. If your inverter stops working after 15 years, a new and improved model is probably ready to replace it.

Check with the manufacturer about their policy and extended warranty options; you purchase extended warranties directly from the inverter manufacturer. 

On the other hand, Off-grid inverters have shorter warranties due to their potentially harsher conditions. These warranties typically last up to five years, but some companies offer 10-year warranties for select models. 

Although it’s always wise to opt for a warranty extension, check out all of the little details mindfully. For example, some warranties will not cover the cost of labor but do cover the cost of parts. If you plan to swap out the inverter by yourself, this detail may not bother you; however, if you have to pay a contractor to handle the labor, you’ll pay more. 

Maintain and Replace Batteries

Taking care of your solar energy system’s batteries is another expense that off-grid owners must consider; even lower-upkeep types of batteries, such as sealed lead-acid and lithium batteries, require inspection a few times every year.

Most battery warranties vary from three to 10 years, depending on the brand. However, if you don’t properly maintain your batteries, they’re liable to fail in their first year. For example, lead-acid batteries need a full recharge after use; they’ll suffer permanent damage if you neglect to recharge them for extended periods.

Most high-quality deep cycle batteries designed for off-grid systems last up to 15 years, depending on the type and how you use and maintain them. Like with other batteries, you can extend the life of deep cycle batteries with proper care and installation.

The best way to take care of your solar energy system is to make sure it’s done right from the beginning; account for the battery capacity, inverter output, and solar power to ensure everything works as it should.

Consider Efficiency Loss

It should come as no surprise at this point that you probably won’t need to replace your solar panels before the end of their warranty; this efficient technology lasts longer than the rest of the system’s components. 

However, efficiency loss could lead to your system failing to cover your energy needs. If your energy use grows or your system output shrinks, you can add compatible parts to it to add capacity.

Next Steps

Impact Energy is a full-service solar company with years of experience installing high-quality American-made solar panels. All of our equipment uses a sleek, low-profile design to provide a streamlined look for your efficient, long-lasting grid. Contact us today to learn more about how we can meet your energy needs!

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