7 factors that affect the performance of your solar system
Key takeaways
- The efficiency of your solar system can be affected by environmental or weather conditions, your equipment and the setup of your solar system, and the efficiency of your inverters.
- There are some small changes you can make in many of these areas to increase the efficiency and performance of your solar panels.
- Choosing a microinverter system over a string inverter system can have one of the biggest impacts on solar system efficiency.
Installing a solar system can be a big investment, so most homeowners are always looking for ways to maximize their ROI by making their installation as efficient as possible.
That’s why it’s so important to understand the factors that can affect the efficiency and performance of your solar panels. Some of the factors are outside of your control, but there are plenty of small changes that you can make to ensure you generate as much energy as possible, as efficiently as possible.
Environmental factors
You can’t control the weather – but there are some small changes you can make to ensure that your solar panels adapt well to environmental conditions.
Irradiance
NASA defines irradiance as the amount of light energy hitting a surface – for our purposes, that means the amount of sunlight that hits your solar panels at any given time.
The relationship between irradiance and solar power performance is pretty simple: If your solar panels are getting less sunlight, they’ll produce less power. On the other hand, the higher the irradiance, the more power your solar panels will generate.
Some of this is outside of your control – you can’t affect whether or not the sun shines – but you canoptimize the performance of your panels by placing them so that they get as much sunlight for as long as possible every day. We’ll talk more about how to do this below.
Temperature
The higher the temperature, the lower the output of your solar panels.
This might seem counterintuitive at first, because light and heat are so closely tied together in our minds. But there’s a solid scientific reason behind it. When a solar panel heats up, the voltage of the semiconducting material in the panel drops, which reduces the panel’s output.
Temperature can have a significant impact on a solar panel’s performance. This graph shows the relative voltage (x axis) and power (y axis) of a solar panel at different temperatures.
As a result, high temperatures can reduce the output efficiency of a solar panel by between 10% and a whopping 25%.
Solar panels are generally tested at about 25°C and are rated to perform at peak efficiency between 15°C and 35°C.
You can find out exactly how much your solar panels are affected by temperature by checking the temperature coefficient on the manufacturer’s data sheet. The temperature coefficient shows how much power your panels will lose for every degree the temperature climbs over 25°C. For example, if the temperature coefficient of a panel is about -0.3%, the efficiency of the solar panel will decrease by 0.3% for every degree the temperature climbs above 25°C.
To avoid overheating your solar panels, you might want to try the following:
- If your panels are on your roof, leave at least a between your panels and the roof, so that air can easily circulate underneath the panels and keep it cool.
- If you’re using a traditional string inverter on your installation, move it into a shaded area. Alternatively, you can use microinverters; in addition to improving the overall efficiency and reliability of your solar system, these are installed directly underneath the panels, meaning they’re always in shade.
- Install white- or light-colored roofing that reflects sunlight around your panels.
- Look into ground-mountedsolar panels if you live in a hot climate.
Equipment and setup factors
The way you set up and maintain your solar system can also have a huge impact on its efficiency and performance.
Solar panel degradation
Like all technology, solar panels gradually degrade over time. The older they are, the less electricity they will produce. But don’t worry – solar panels usually take a long time to degrade, and most manufacturers guarantee at least 90% performance for the first 10 years, then 80% for the remaining 15-20 years of the panel’s life. Overall, you can expect your panels to degrade at a rate of 8-14% during the first 25 years after they’re installed.
The older a solar panel becomes, the less electricity it produces. This graph shows how different solar panels degrade over time.
The biggest contributor to degradation is the wear and tear that comes from solar panels being exposed to the elements. Wind, rain, and snow wear down the panels and create tiny cracks in the solar cells, corrode the panels’ frames, or harden the crystalline silicone, all of which can disrupt the power generation process.
Some of this is inevitable – you’ll rarely be able to completely protect your panels from the elements – but there are some things you can do to slow down solar panel degradation. This includes:
- Buying higher-quality solar panels
- Making sure solar panels are installed correctly, without being scratched or damaged in the process
- Installing panels at the right angle so that they can “self-clean” efficiently when it rains or snows
- Keeping up proper maintenance to remove any build-up of dirt or debris that might block the sunlight
Solar panel orientation and tilt
It’s simple: If you want your solar panels to generate as much energy as possible, you need to make sure they’re positioned to catch as much sunlight as possible across the span of a day.
Solar panels are most efficient when the sun’s rays are perpendicular to the surface of the panels – but, as the sun moves across the sky in the course of a day and through each season, the sun can’t always be in the perfect position.
So the key is calculating the azimuth angle– the compass direction from which the sun is shining – for your location, and placing your panels at a tilt that keeps them perpendicular to the sun for as long as possible. That means:
- If you’re north of the equator, your panels should be facing south. If you’re south of the equator, they should be facing
- The angle at which your panels are tilted depends on the latitude of your home, as this will determine the azimuth angle for your location. In the US, the best angle is generally somewhere between 30 and 45 degrees.
This diagram shows how the azimuth angle of the sun changes depending on your geographical position. To get the most value from your solar panels, you need them to be at an angle that catches the most sunlight. This diagram shows the difference between adopting a low tilt angle and a high tilt angle for your panels.
Of course, the position of the sun changes throughout the day, so a static panel won’t always be at the perfect angle to catch the sun. That’s why some homeowners use that adjust the position of your solar panel over the course of the day, so that the angle is optimized for as long as possible. These can be particularly valuable in areas that get less sunlight, or experience capricious weather.
Shading and soiling
If any part of a solar panel is blocked from the sun – either because the solar panel is in shade, or because dirt and dust is obscuring the surface of the panel – then the output of that panel will plummet.
But the effects aren’t limited to just one panel. If you’re using a traditional string inverter in your system, when the output of one panel drops, the output of every panel in your system drops to the same level.
If you want to maximize efficiency and performance, invest in a microinverter system instead. When you use microinverters, each panel in your system functions and converts power individually. So if one panel falls into shade or gets dirty, the rest of your panels will keep working just as efficiently as before.
Inverter efficiency
It’s not just your solar panels that can affect the performance of your solar installation – the inverters you use to convert DC to AC power can make or break the efficiency of your system.
Conversion efficiency
When your inverters convert direct current to alternating current, a small amount of energy is always lost. This is because inverters need some power to actually do the task of converting the current.
There isn’t much energy lost here – the best inverters for household use tend to be between 96-98% efficient. But there is some variation between different inverter brands, so keep an eye on the conversion efficiency of your inverters when you’re building your solar system.
MPPT efficiency
MPPT stands for maximum power point tracking. The MPPT controller sits inside an inverter and tracks fluctuations in the maximum power point of each solar panel, ensuring that the inverter is always converting as much energy as possible at any given moment. You can read more about MPPT and why it’s so important here.
This is another reason why multiple microinverters are often better for the performance of your solar system than string inverters. In a standard string system, there is only one MPPT controller converting power from multiple solar panels in series – so, as we discussed above, if the maximum power point of one panel drops, the MPPT controller will act as though the same has happened to all of the panels. But a microinverter system has individual MPPT controllers for each panel and isolates panels from each other, so the maximum power point of each panel is measured individually.
Different inverters have different levels of MPPT efficiency, depending on the quality of the algorithm they use to track the maximum power point of a panel. Hoymiles microinverters, for example, have an MPPT efficiency rating of 99.8% when used in real-world conditions.
Want to maximize the efficiency of your solar system? Choose microinverters
As we’ve seen, there are lots of factors that can affect the performance of your solar system – and lots of changes you can make to increase its efficiency.
But if you’re looking for one way to maximize the power your system generates, then choosing microinverters over a traditional string inverter can have a major impact. The right microinverters can affect everything from how shading affects solar panel performance to how much energy is lost during the conversion from DC to AC.
The efficiency of solar panels has dramatically increased over the past decade. While with time the cost of solar panels has fallen more than 80% over the last eight years making solar panels a very lucrative investment.
When you plan to buy a Solar Power System, many companies will promise many things about efficiency, savings and long term advantages with different solar technologies.
Many people are unaware of what factors affect the output of Solar Power System. Hence SolarSmiths today is going to take you in-depth about factors that influence solar energy production. Understanding these factors will help you to become a smart buyer who can make correct decisions.
Let’s understand the factors that affect the output of Solar Power System:
1. Weather Change
Lot of us assumes that high temperature leads to high solar panel efficiency, but it is just a myth.
As heat exposure can prematurely degrade solar cells as for daily production, high temperatures lead to a drop in voltage and a drop in overall power.
Solar cells perform better in the cold rather than in hot climates, such as if solar panels are exposed to 25˚C, which can be significantly different from the real outdoor situation.
Hence whatever single temperature rises above 25˚C the solar panel output decays by about 0.25% for amorphous cells and about 0.4-0.5% for crystalline cells.
Thus, in hot summer days, panel temperature can easily reach 70˚C or more where the panels will put out up to 25% less power compared to what they rate for at 25˚C.
Therefore in most of India when the temperature is High about 45 ˚C and high demand for electricity in April/May/June, a 100W panel will produce only 75W.
2. Shading
Shading is same as a clog in the pipe of running water, as it restricts the water in same pipe way solar cell is shaded, when the shadow falls on even a small part of the solar panel the current through the entire string is reduced.
The cells within a panel are mostly connected wired in series, and the shaded cells affect the current flow of the whole solar power system. But in real life, there will befall of shadow some or the other day; hence partial shading should be considered while planning the installation.
If the affected panel is wired in series (in a string) with other panels, then the output of all those panels will be affected by the partial shading of one panel. In such a situation, an obvious solution is to avoid wiring panels in series if possible.
3. Roof Orientation
The positioning of the solar panel must be facing a south direction for those living in the Northern Hemisphere and the sun is always along the southern part of the sky. Hence it is generally the best practice to position solar panels facing south to capture the maximum amount of sunlight overall.
The south-facing solar panels should be tilted between a 30- and 40-degree angle so that behind this angle specificity is to ensure sunlight hits panels at a perpendicular angle, which produces the most energy. An edge along these lines also helps snow to slide off of solar panels more quickly during winter in the northern latitudes.
The angle of inclination of the solar panels should be actively adjusted according to changes in seasons, latitude and longitude and sunshine hours.
4. Cleanliness of Solar Panel Surface
The cleanliness of the solar panel surface is directly connected to photoelectric power conversion. Due to polluted environment, rainfall, snow, dust, sandstorms are few factors can play a role in reducing the efficiency of solar module hence ensure cleaning frequency of the solar panels according to the local labour cost.
In most places, there`s more pollution in the winter; hence spring is the best time to do an annual cleaning. While once solar panels are cleaned once or twice a year they will produce 3.5% and 5.1% more electricity compared to uncleaned.
5. Location
Not all places have the same abundance of annual sunshine. To decide the amount of solar radiation received in your home isolation is a tough job in designing a cost-effective solar array for your usage.
Insolation is identified by elements such as local weather, the time of year, and most importantly, the latitude of your home orcompany.
Depending upon the season there will be a different climate in different locations; hence your solar panel’s production numbers will be different according to the season remember to consider annual production.
CONCLUSION
We must say that even the best solar panels can have their efficiencies significantly affected by environmental factors though with proper design if the above factors are not considered. We understand your major motive of going solar is to save money on your utility bills.
Insolation is identified by elements such as local weather, the time of year, and most importantly, the latitude of your home orcompany.
Depending upon the season there will be a different climate in different locations; hence your solar panel’s production numbers will be different according to the season remember to consider annual production.
In PV plants, the input is the value of radiation from the sun, and its output is electrical energy. While generating electrical energy, many meteorological factors are affecting the performance of the PV plants. These factors lead to losses in the production of electrical energy. Investors want to minimize these losses to avoid financial damage. Losses can occur due to meteorological factors as well as the design of solar PV plants. These can be shading, material quality, incompatibilities between parts, and inverter losses.
The losses that may occur in a solar power plant are shown in the image below.
The maximum electrical energy that can be produced in solar power plants can be determined. If the plant produces less energy than the maximum energy required, it means that there are losses in the plant. We can classify these losses into three main headings.
- Irradiance losses
- System losses
- Inverter losses
1.IRRADIANCE LOSSES
It is a situation related to the angle at which the solar panel is placed. The greater the amount of solar radiation coming into the photovoltaic module, the more energy the panel will produce. Minimizing the losses, that may occur in the radiation value received by the panel, will provide an efficient solar power plant.
REFLECTION LOSSES
It is the losses caused by the reflection loss on the PV module before the radiation reaches the cell. In the photovoltaic modules, the reflection is minimized by using protective coatings to prevent this reflection. According to the data obtained under normal irradiation conditions, the modules reflect 4% of the incident radiation.
SHADING THE HORIZON
It is the shading caused by factors such as mountains and hills in the area where the power plant is located. Horizon shading is generally equal at all points of the plant.
PANELS ROW SHADING
The shading of the solar panels on other modules is called modules row shading.
DUSTING AND SNOWING LOSSES
The amount of solar radiation coming to the solar panels decreases due to the dirtiness of the surfaces of the panels. For this reason, this effect is called the dusting effect. In this case, the panel surfaces should be cleaned until it can absorb sunlight sufficiently. Losses caused by snowfall are evaluated under this effect also.
2. SYSTEM LOSSES
There are designated parameters that need to be paid attention to while designing in the PV plant. There are losses due to the design parameters. The differences between the catalogue values and actual values of the solar panel cause the deviations in the panel technical features. These deviations cause system losses.
LOW IRRADIANCE LOSSES
They are the losses seen in the power output of the PV plant due to low irradiance.
TEMPERATURE LOSSES
There is an inverse proportion between the photovoltaic power output and the module temperature. If the module temperature increase, the received power decreases. Cell temperature is directly proportional to losses caused by temperature. When the ambient temperature where the panels are located increases, the cell temperature also increases. Therefore, the energy produced by the panel decreases.
INCOMPATIBILITY LOSSES
Environmental effect is relevant to the panel’s damage due to the weather condition. If PV modules are at different operating temperatures or exposed to different irradiance values, we can consider this loss as a loss of incompatibility.
CABLE LOSSES
Cable losses are caused by ohmic losses in DC and AC cables used in photovoltaic systems.
3. INVERTER LOSSES
The inverter losses are calculated through the inverter efficiency curve, considering the energy consumption of the inverter at standby condition as well.
Standards such as European Standards are used for DC/AC power cycle efficiency calculation. DC/AC conversion losses in the inverter depend on the type of power layers and operational characteristics such as conduction and switching of semiconductor, magnetic elements, and capacitors used within the PV inverter.
As an example, PV inverter efficiency decreases 0.3% – 1% per 150 V DC input voltage amplitude. Also, the efficiency decreases down to 5% due to the power consumption of the control unit and switching losses in low irradiance and high DC input voltages. The maximum efficiency and European efficiency of the transformerless grid-connected inverters nowadays are around 98%.
WEATHER STATIONS REDUCE THE LOSSES TO THE MINIMUM LEVEL?
It is necessary to anticipate losses before preventing them. Anticipating losses in advance will help to obtain the maximum efficiency from the system. Otherwise, the desired performance and income will not be obtained from these costly systems. So, Weather Stations can be the optimal solution.
The Weather Station used in these systems provides data. As a result of evaluating these data, the performance of the system operation is evaluated and losses are minimized.
Seven Sensor, as Weather Stations manufacturer, sells Irradiance Sensor, Module Temperature Sensor, Ambient Temperature Sensor, Wind Speed Sensor, Wind Direction Sensor, and Relative Humidity sensor to build efficient Weather Stations to provide accurate data to system for evaluating the losses of the energy generated by PV Plants. You can visit our website for more detailed information about the Weather Stations we are producing.
The energy flow path of a grid-tie solar system usually contains a solar panels, a combiner box, a DC power distribution cabinet, an on-grid inverter, an AC power distribution cabinet, and the connection cables.
Based on the energy flow of the PV system, it is necessary to fully consider the six important factors affecting the conversion efficiency in the design of the solar power system.
Climate conditions
The solar panel modules are exposed in the natural environment for a long time, and factors such as wind and lightning will affect the solar cell. Light, wind, temperature and so on will change the photoelectric conversion efficiency of solar panels (cells), and some factors may even damage the functions and structures of the solar panels. It is required to fully collect the meteorological and environmental monitoring data in the solar power system design process.
Angle of inclination of solar panel
The solar panels need to absorb sunlight at the best angle, so that they can really play the role of improving the photoelectric conversion efficiency. Under different seasons, geographical locations and sunshine conditions, the optimal angle of inclination of solar panel will also have great changes, so the angle of inclination of the solar panels should be actively adjusted according to changes in seasons, latitude and longitude and sunshine hours. The fixed inclination angle should be chosen as the angle of inclination based on the maximum power generation in the whole year.
Cleanliness of solar panel surface
The cleanliness of solar panel surface also affects the photoelectric power conversion. It is required to know much about the actual situation of solar panel to be polluted in the environment, determine the contamination of the solar panel surface, especially the impact of strong wind, strong convection and sandstorm weather on the surface of solar panel, and then determine the cleaning frequency of the solar panels according to the local labor cost.
Solar panel spacing design (Shading)
Once the solar panel is sheltered, it will affect the power generation capacity of the solar system. Therefore, when designing the solar panel array spacing, it is necessary to consider the shading of the building to the solar panels and the self-shading between solar panels.
MPPT tracking accuracy
As the sunshine and temperature change, the output voltage of the solar panels changes accordingly, and the output power of the PV array will change as well. The goal of maximum power point tracking (MPPT) for the solar inverter is to enable the PV array to achieve maximum power output in case of any sunlight and temperature change, so the accuracy of the MPPT greatly affects the system efficiency. Now, the solar charge controller is also widely used to track the maximum power point of solar power generation in real time. Our MPPT solar charge controllers including 20 Amp to 60 Amp have high charging efficiency over 98.5% and tracking accuracy over 99.73%.
Power loss of each part
The power loss of the RV system in energy conversion and transmission process includes:
- Solar panel matching loss
These losses are caused by the series connection of solar panels in different light conditions. - Loss of deviating from the maximum power point
The power loss is caused by temperature influence, maximum power point tracking (MPPT) accuracy and so on. - DC line loss
According to the relevant standards, the cable loss needs to be controlled within a certain range. - Conversion loss of solar inverter
Different operation power points affect efficiency in the DC/AC conversion process. - Loss of AC grid connection
The transmission efficiency from the inverter output to the high voltage grid is mainly considered to the transformer efficiency.
