The solar panel is also afraid of high temperature

No introduction

The weather has been too hot recently, not only in Asia, but also in Europe, and even at the North Pole! How to deal with this terrible temperature? What else can ordinary people do besides turn on the air conditioner? But what we can do when out of power? Especially now that energy is in short supply and the prices of various energy sources are rising rapidly, Some people has considered using solar energy to support household electricity. But what we don’t know is that the solar panel is also afraid of high temperatures.

solar panel also afraid of high temperature

So the question is, do solar panels produce more electricity as the temperature rises?

It is said that under this kind of weather, the solar power generation in the UK reached 66.9 GWh in one day in July, which can meet 8.6% of the national demand. It is said that Germany has also reached a new single-day high in solar power generation.

Could it be said that there is so little benefit to extreme heat?

But, I’m so sorry, your thinking is so naive.

Solar power generation is also afraid of high temperatures!

The principle of solar power generation is essential to use the photovoltaic effect generated by light irradiation of semiconductors to directly convert light energy into electrical energy. Specifically, by irradiating sunlight on the PN junction formed by the contact between the P-type semiconductor and the N-type semiconductor, after the PN junction absorbs the energy of the photon, it excites electrons and holes (moving in opposite directions), so that charges of opposite signs appear. The accumulation forms positive and negative poles, which generate a voltage. From this perspective, more light energy does produce more electricity.

But, high temperature does not equal more light energy (even without sunlight the ambient temperature can be very high).

Temperature affects the efficiency and maximum photovoltaic output of solar panels. 

The hotter the panel, the less power it produces. Ambient temperature, the temperature coefficient of the actual panel, and the type of installation are all factors that affect the power generation potential of a solar power system.

Every solar panel has a temperature coefficient.

Every solar panel will have a temperature coefficient that tells us how quickly the solar panel’s efficiency decreases when the temperature rises by 1 degree Celsius (33.8°F). 

For example, when the temperature coefficient is negative 0.6%, that means a 0.6% reduction in efficiency for every degree above 25°C (or every 33.8 degrees above 77°F). The better solar panels have higher temperate tolerance. Therefore, this parameter needs to be considered when purchasing solar panels.

It is usual for solar cells to reach 65°C on a hot summer day, but high temperatures can reduce panel efficiency by as much as 26%, resulting in significantly less power output.

Mounting type can change the temperature

Mounting type can change the temperature

Other Ways to Change Temperature

Passive cooling methods: 

White or light-colored roofs also help reduce the temperature around the panels, as these colors reflect sunlight more and are not heated as much as darker roofs.

Active cooling method:

For example, fans that blow air across panels, water cooling systems

Side note: Be careful rinsing the panels with cold water during the hottest part of the day! Because domestic solar power is mostly glass components, a sudden burst of glass can damage your solar panels irreversibly. Systems with water cooling are cooled by continuously circulating water through the pipes to absorb heat from the panels, and this water can be heated and used for showers in the home.

Calculate temperature derating

Calculate temperature derating

Actual project case:

power generation and revenue change chart

In one year’s power generation parameters, the power generation was the highest in May and June and began to decline month by month in July and August. This is very normal.

High temperature also seriously affects the working efficiency of semiconductors.

Affected by its nature, the temperature stability of the semiconductor is extremely poor, and it must be kept within the range of 20 ° C ~ 30 ° C to work normally.

be careful of fire

In addition, high temperature will also produce effects such as hot spot effect and PID effect.

The hot spot effect means that some components in the series branch are “shielded” for some reason, not only unable to generate electricity but also used as a load to consume the energy generated by other branches.

Once a high-temperature day occurs, the local high temperature will be aggravated, and the hot spot effect will be strengthened, which will directly lead to the aging and damage of the module panel.

After all, as a “big board” exposed to the outside world, photovoltaic panels will inevitably be polluted, such as bird droppings.

In normal times, bird feces will cause a small resistance, but when high temperature occurs, it will aggravate its impact, and it is very easy to burn out components.

In addition to this, the PID effect (potential induced decay) is also exacerbated with high temperature and humidity.

Since high-temperature weather is often accompanied by humidity, a large amount of water vapor in the air will enter the inside of the module through the edge-sealing silica gel or the backplane, which will cause a large amount of charge inside the module to accumulate on the surface of the cell, resulting in serious performance degradation.

Overall, the optimal temperature for photovoltaic power generation is 25 °C, and the temperature is too high, which will affect power generation.

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ERICSITY leverages its advantages in electrification, industrial automation and material science and technology, focuses on the global popularization of PV and the continuous improvement of energy efficiency.

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