In this article, we are addressing some common yet important questions that arise in solar power plants. We hope to provide a comprehensive understanding of solar power plants in a deep yet easy-to-understand manner, enabling readers to gain valuable information and make solar energy and new energy familiar to them.

Several common questions and answers.

How exactly is electricity from solar energy produced?

Photovoltaic solar energy generation refers to the method of power generation that directly converts light energy into electrical energy. It includes photovoltaic power generation, photochemical power generation, photosensitive power generation, and photobiological power generation. The most commonly used at present is the direct power generation method which effectively absorbs solar radiation energy through photovoltaic cells and converts it into electrical energy.

Solar photovoltaic panels are a battery system consisting of series and parallel single-cell batteries, also known as battery modules (arrays).

A single cell is a silicon diode. According to the electronic characteristics of semiconductor materials, when sunlight shines on the P-N junction made of P-type and N-type two different conductive types of homogeneous semiconductor materials, under certain conditions, solar radiation is absorbed by the semiconductor materials, The non-equilibrium carriers i.e., electrons and holes are generated in the conduction band and valence band.

Due to the strong static electric field in the P-N junction, it can form a current density with an open-circuit voltage under light. If electrodes are led out from both sides of the built-in electric field and connected to the load, the P-N junction, connecting circuit and load form a loop, and there is "light-induced current" flowing through, then the solar cell module can achieve power P output to the load.

Simply put, the principle of power generation of photovoltaic panels is that the light makes the diode generate a static electric field. After connecting to form a circuit, the static electric field has a current, and our photovoltaic panel can generate electricity.

What’s the difference between solar PV panels and solar thermal panels?

  • Different principles of power generation:

    Photovoltaic panels directly convert light energy into electrical energy.

    Solar thermal panels use mirrors or lenses, using optical principles to gather sunlight from a large area into a relatively small focusing area, causing solar energy to concentrate.

    The focusing area on the generator rises in temperature due to exposure to sunlight, and the principle of light-heat conversion turns solar energy into thermal energy. The thermal energy drives the generator through a heat engine (usually a steam turbine engine), thereby achieving the purpose of power generation.

Solar thermal panels
  • Differences in energy storage methods.  The photovoltaic system is affected by sunlight, and excess energy can only be stored in batteries; for solar thermal power generation, the heat generated by solar energy can be temporarily stored, for example, in high-temperature molten salt. Such stored energy generates electricity more stably.
  • Different scales and suitable scenarios.
    Photovoltaic power generation devices are relatively simple, and the requirements for light exposure are relatively low, more suitable for miniaturization development, that is, smaller scales, such as homes, residential communities, balconies, etc.
  • Solar thermal power generation has better compatibility with traditional thermal and hydroelectric power and is suitable for large-scale development. That is, the scale is larger. And due to higher requirements for light exposure conditions, it is more suitable for areas with good light exposure.
  • Photovoltaic power generation is mainly used for distributed power generation, while solar thermal power generation is often used for concentrated power generation.
  • Different detection devices are needed:Photovoltaic power stations need to detect dust, solar incident angle and surrounding environment, etc. For solar thermal power, tests are needed for solar water heater performance, thermal performance of solar collectors, etc.
Cloudy day PV system

Can solar power be generated on a cloudy day?

After we complete the installation of the photovoltaic system, we will consider making the photovoltaic panel work as long as possible, and you asked, "Can solar power be generated on a cloudy day, or on a rainy day, or at night?"

  • First of all, according to the principle of photovoltaic cell power generation,  PV solar panels can use both direct and indirect light to generate electricity. As long as there is light, the cells can generate electricity.

Solar panels work most efficiently and generate the most electricity when they absorb direct sunlight on bright sunny days. When the light is partially blocked by clouds, the solar panels can still work, but their power generation capacity will be weakened, and they can only produce 10% to 20% of the normal output power.

Cloudiness usually accompanies rainfall, and here's a surprising fact: Rain actually helps solar panels work more efficiently. This is because rainwater washes away any dust or dirt accumulated on the panels so they can absorb sunlight more efficiently.

Do solar panels work at night?

At night, without light, the photovoltaic system cannot work. The reason is simple: The working principle of solar panels is known as the photovoltaic effect, where solar cells are activated by sunlight to generate electricity. Without light, the photovoltaic effect cannot be triggered, and electricity cannot be generated.

Will the photovoltaic system work and generate electricity when it is illuminated by street lights at night?The brightness of street lights is too minimal, so although photovoltaic cells can generate electricity, the current is very small, and the power generation can be completely ignored.

How is more solar power being brought into our electricity systems?

Regarding plans to add more solar energy into the power grid system, the most effective way to is to increase the number of photovoltaic panels, which can directly increase solar power generation.

Other methods include regularly cleaning your solar photovoltaic panels, adjusting the photovoltaic panels according to the seasons to maximize the reception of solar radiation, avoiding shadows on the surface of the photovoltaic panels, and a slight shadow can cause the efficiency of the photovoltaic panels to drop by half.

If your residential solar system can no longer be increased, you can also increase the battery energy storage system to improve the existing solar energy utilization efficiency. Storing excess electricity in batteries can collect and use during periods of poor sunlight, including nighttime and particularly cloudy weather.

Home energy storage battery to choose the most appropriate capacity

In terms of battery capacity, the choice is generally based on household demand and the capacity of the established photovoltaic system. The recommended capacity of the energy storage battery is the average electricity use for one to two days of the household.

If your home uses an average of 6 degrees of electricity a day, then we recommend 5kWh or 10kWh of energy storage batteries. In this way, when the battery is fully charged, the night electricity consumption can be supplied by the battery, reducing the use of grid electricity during peak electricity price periods.

Home energy storage battery to choose the most appropriate capacity

In terms of battery capacity, the choice is generally based on household demand. The recommended capacity of the energy storage battery is the average electricity use for one to two days of the household.

If your home uses an average of 6 degrees of electricity a day, then we recommend 5kWh or 10kWh of energy storage batteries. In this way, when the battery is fully charged, the night electricity consumption can be supplied by the battery, reducing the use of grid electricity during peak electricity price periods.

We will continue to answer questions about photovoltaic systems, products, scheme design, construction, etc. If you have any questions about photovoltaic systems, or want to consult for more specific information, you can contact us at email.

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