25 years(or longer).This is the industry warranty standard for first-class manufacturers.In fact,the service life of solar panels is much longer than that.The warranty generally guarantees that the panel can work at 80%higher than its rated efficiency after 25 years.A study by NREL(National Renewable Energy Laboratory)shows that most panels can still generate energy after 25 years,although the energy decreases slightly.
Investing in solar energy is a long-term activity.The upfront cost may be high,but over time,the investment will recover the cost through the monthly energy cost saved.
For customers who try to invest in solar energy,the first question we often receive is:”how long can solar panels last?”?
The warranty period of the panel is usually 25 years,so it can meet your time expectations.But in fact,the research shows that the panel will still operate with low efficiency for a long time after the warranty expires.
Let’s calculate:solar panels lose 0.5%to 1%of their efficiency every year.At the end of the 25 year warranty period,your panel should still generate energy at 75-87.5%of the rated output.
According to NREL research,nearly 80%of solar panels have a service life beyond their warranty period.
Standard solar panel warranty
The standard warranty period of solar panels is 25 years.During this period,the manufacturer guarantees that the panel will operate at or near peak efficiency.Most panels will produce at least 80%of their rated output during the warranty period.
For example,a 300 Watt panel should produce at least 240 watts(80%of its rated output)at the end of the 25 year warranty period.
Some companies offer a 30-year warranty or promise 85%efficiency,but these are outliers.
The standard is 25 years and the efficiency is 80%.
Solar panels also have a separate process warranty to cover some manufacturing defects,such as junction box or frame failure.Generally,the process warranty period is 10 years,and some manufacturers provide a 20-year process warranty.
So how long can solar panels last,really?
So what will happen after the 25 year mark?The panel output at 80%efficiency is still valid,right?
There is no question here-the answer is yes!If your panels still output energy,there is no real reason to replace them.
Panels often generate energy long after the warranty expires.According to a 2012 study by the National Renewable Energy Laboratory,the average attenuation rate of the panel is between 0.5%and 0.8%per year.
Output power attenuation of photovoltaic module:
The attenuation rate of photovoltaic module refers to the ratio of the output power and the nominal power under the standard test conditions(AM1.5,module temperature 25℃,irradiance 1000W/m2)after the photovoltaic module operates for a period of time.
Output power attenuation of crystalline silicon photovoltaic module:
The first stage is called the initial photoinduced attenuation,that is,the output power of the photovoltaic module decreases by 1%~2.5%in the first few days of use,but then tends to stabilize.
The second stage is called the aging attenuation of components,that is,the extremely slow power decline during long-term use.The main reason is related to the slow attenuation of batteries and the performance degradation of packaging materials.Manufacturers of crystalline silicon components generally provide 25-year power warranty.It is generally promised that the power at the end of the 10th year will not be lower than 90%of the initial value and at the end of the 25th year will not be lower than 80%of the initial value.
In the third stage,the PID electric potential energy induces attenuation(the battery sheet discharges to the module frame,that is,the packaged photovoltaic module has weak leakage phenomenon)
In fact,78%of the test systems have an annual decay rate of less than 1%.This means that after 25 years of use,about four fifths of solar panels still operate at 75%or higher efficiency.At this point,it can be estimated that your solar panel will still generate a certain amount of energy for a long time after the warranty period ends.
What does this mean for your ROI?
This is good news if your main concern is to achieve a positive return on investment(ROI)on your system.
Most of the estimated distributed PV benefits are based on a 25 year warranty period.Any increase in power generation beyond 25 years is an additional benefit.
We cannot guarantee that the panel will exceed its warranty period(after all,this is the focus of the warranty).However,in fact,most panels will still generate power with reduced power for a long time after the end of their service life.This is because the solar panel is very reliable without any moving components.
If your photovoltaic power generation system returns within the warranty period and your battery panel can continue to generate electricity,your return on investment will far exceed the project income estimated by us.
How to prolong the service life of photovoltaic system
Solar panels may be the longest part of your solar system.You still need to maintain or replace the inverter and battery to keep everything running normally.
The service life of the inverter is shorter than that of the photovoltaic module.No matter what type of system you have,you need to replace it.
The best way to protect your investment is to thoroughly check and accept the entire system during installation,and check your bracket to ensure that components and wiring are secure.The biggest threat of photovoltaic modules is physical damage or electrical failure caused by improper installation.
Replace the inverter after 10 years
Most grid connected inverters have a 10-year warranty,and many manufacturers offer the option of upgrading to a 20-25 year warranty.
Extending the warranty period of the inverter is a wise investment.The inverter shall be replaced at least once before the warranty period of the photovoltaic panel expires.If your inverter fails after 15 years,it may be replaced by newer and better models.
Consult the inverter manufacturer for their extended warranty options and policies.The extended warranty is purchased directly from the manufacturer.When you purchase an extended warranty,please check the small details carefully.Some include parts costs,but not labor costs.
Maintenance and replacement of batteries
Battery maintenance and replacement is one of the main costs related to off grid system.Even battery types with low maintenance costs,such as lithium batteries and sealed lead-acid batteries,still need to be inspected several times a year.
Most batteries have a warranty period of 3-10 years,depending on the brand.However,if you do not properly maintain the batteries,they may fail within the first year of possession.
For example,the lead-acid battery needs to be fully charged after use,and it will be permanently damaged if it is left uncharged for a long time.
The service life of most high-quality off grid deep cycle batteries is between 5-15 years,depending on the battery type and their use and maintenance mode.You can prolong the service life of the battery by proper maintenance and ensuring the correct installation of the battery.
When you start to plan to install the distributed photovoltaic system,demonstrate in advance the cost-effective energy storage batteries,solar panels with installed capacity above the standard and inverters with stable performance to keep the system working normally.