Solar Hours per Day: How They Affect Average Solar Panel Output per Day

Introduction

This article will clarify how solar panels do not generate all the electricity from sunrise to sunset. It depends on how many solar hours per day reach the solar panels. ‘Solar hours per day’ measure reflects the real strength of sunlight reaching the solar panel. To predict the average solar panel output per day, one must understand that this factor is very important. By depending only on daylight hours, homeowners, businesses, as well as installers generally overestimate the production. More significantly, geography, weather, and installation settings determine how many usable hours of strong sunlight panels receive per day.

What Are Solar Hours per Day?

The solar hours per day represent the hours where the light of the sun is intense enough to generate energy at a rated capacity. This is different from the total hours of daylight. A city may get 12 hours of daylight; however, only 4-6 hours of that time will provide the sunlight to perform efficiently in panels.

The daylight hours are from sunrise to sunset. However, power generation in panels will start as soon as there is light present. Yet, in the morning or the evening, the number of sunrays is lower. So the rate of power generation will be low. When the accumulation of light rays reaches 1000 watts per square meter, the sun hours become the peak hours. This usually occurs at 12 pm when the sunrays are the strongest.

The panels in the labs perform under standard conditions, with a constant current. They perform 1000 W/m2 of irradiance at 25°C. As the temperature, weather, and location differ, the performance is different at different places. For instance, places near the equator line receive a fixed amount of solar hours in vertical distribution. But places in the north receive fewer sun hours due to seasonal changes. Hence, two systems with the same specs can deliver different experiences depending on their location.

Why Solar Hours Matter for Average Solar Panel Output per Day

The amount of average solar panel output per day depends directly on how many solar hours are available in a location. Your everyday solar panel productivity calculation is straightforward: system size in kilowatts x average peak sun hours = daily kilowatt-hour output. For example, a 5 kW solar array with 5 solar hours a day will give you almost 25 kWh of usable electricity.

The formula is essential because there are a lot of differences between different regions. In California, for instance, the number of average solar hours is about 5.5 per day. Thus, the aforementioned 5 kW system will provide almost 27.5 kWh. However, in Germany, with only 3.5 solar hours, the 5 kW system would produce about 17.5 kWh. In some parts of India, there are approximately 6 or more solar hours. So, the same 5 kW would give you about 30 kWh. These are the reasons why, when you want to know the solar panel generates the most energy, you have to look into both the location and the system size.

Factors That Influence Solar Hours and Panel Output

Solar performance depends on far more than sunlight availability. There are many other factors that also play a very important role in the calculation of solar duration and panel output. Sometimes, there are a few places on the surface of the earth where the sunlight duration is 24*7 for a full day.

The seasonal pattern is one of the most significant factors. In Summer, longer days and high solar intensity increase generation, while in winter, sunlight duration and intensity both decrease. Cloud cover also reduces the energy yield. Panels usually operate at about 60 – 80% of their capacity on overcast days.

The geographical location also plays an important role here. The regions near the equatorial line usually experience more consistent solar day times.

In the summer period, the number of solar hours is usually higher. There are a few other factors, too, that are included in the productivity of solar panels. With a south-facing installation in the Northern Hemisphere, or a north-facing installation in the southern hemisphere of the earth, a greater efficiency is usually achieved.

The arrangement of the panels also increases productivity. Panels claimed that the correct angle towards the sun increases the exposure of the panels. The panels covered beneath the trees or buildings may cause a significant loss in solar panels.

Regional Comparison: Solar Hours Across the Globe

How many hours of sunlight a region receives per day varies greatly across the continent. This is why solar panel adoption isn’t the same everywhere. Some areas had longer sunlight than others

Germany had an average of a solar panel being under 3.5 hours to 4.5 hours. That is not a lot in comparison to the United States or even India, but Germany is among the top solar panel adopting countries, due to their policies.

Studies show, southern areas of the United States, like Arizona or Texas, have over 6 peak sun hours each day. However, the northern states of the US have under 4 peak sun hours. China’s average sunlight was 4-5 hours, India had 5-6, and the Middle East is likely to have more than the average sunshine. The Middle East region, especially Saudi Arabia, receives more than 6.5 hours of sunlight each day.

South Africa and Kenya, in Africa, received very long durations of sunlight; thus, solar panels were practical for both their urban and rural electrification. In Australia, data shows average sunshine hours are 5.5 or higher. For this reason, identical systems produced varying results.

A 5 kW array in Germany might produce less than 20 kWh per day on average, but the same system in the Middle East and Australia exceeded 30 kWh per day if sized and oriented correctly.

Real-Life Example: How Solar Hours Impact Residential Output

A medium household generally requires 25-30 kWh/day. In India, which receives an average of 5 solar hours daily in many areas, sizing a system properly becomes a challenging task to meet this demand.

The simple calculation yields that the required size of the system is the daily consumption/solar hour. Let’s, for example, calculate the required system size for the loads of the 30 kWh house. The required system size is known by dividing 30/5 hours, and thus, the system size required will be 6 kW.

Therefore, with correct installation, a 6kw solar system can provide for an average daily use for this household. Moreover, this calculation considers conversion losses as well as transmission. So, at the end of the day, usually 80-75% of the electricity produced is usable electricity. Moreover, in high sunlight availability areas, families can cover their needs without oversizing the system.

The above example demonstrates how much energy does a solar panel produces need not entirely depend on the hours of daylight because varying hours of sunlight interfere. Moreover, a household can predict real average solar panel output per day by sizing the system according to the local sunlight conditions, thus avoiding the performance they had hoped for, as well as avoiding overspending on an oversized system.

Beyond Solar Hours: Other Ways to Maximize Daily Output

While the solar hours per day are crucial to determine the average output, there are other methods and technologies to maximise the daily output of solar panels in households or industries.

High-efficiency modules like monocrystalline or advanced N-type TOPCon have a much better conversion ratio than some older technologies. Thus, in places with moderately lower sunlight, these cells can produce more power.

The system electronics have a major role in it as well. Hybrid inverters such as Deye and Growatt, and other models, get the highest performance along with the flexibility of grid-tied and off-grid applications. These Hybrid inverters let the solar panels work better and control the voltage and other conversion ratios properly. The inverter even helps to increase the efficiency of power conversion and utilise the electricity to its maximum.

Another way to cope with the deficit in the panels’ output is by storing the power when the solar hours are less than required. The LiFePO4 batteries are made in a way that combines long cycle life and stable power output, and these kinds of batteries are now much more in use. Thus, LiFePO4 batteries are now used in most households, especially in countries where days are shorter because of winter or cloudy days.

To reduce the variation during winter seasons in the average solar panel output per day, we need to keep a balance between our requirements and the price we can afford. HBOWA supports installers and businesses around the world with the best quality solar panels and inverters with LiFePO4 batteries.

Conclusion

One of the most important things to know when you want to calculate the number of solar panels’ average output per day is the number of solar hours per day. It is important to know that the production variation by the size of the system, but also by the location, the technology used, and the season. To get reliable performance, planners should count on the efficiency losses and buy good-quality panels. The power of sunlight might fluctuate, so you should also take some storage into consideration to balance the fluctuation of the sunlight. HBOWA provides high-quality solar panels with great efficiency, advanced inverters, and lithium iron phosphate batteries in bulk to installers and businesses all over the world.