A solar power station (also known as a photovoltaic power station or solar farm) is a facility that converts solar radiation into electricity on a large scale through the photovoltaic effect or concentrated solar thermal power generation technology. It is an important renewable energy facility aimed at reducing dependence on fossil fuels and lowering greenhouse gas emissions.
2. Core Working Principle
There are two main technical approaches to solar power stations:
a) Photovoltaic Power Generation:
Core Principle: The photovoltaic effect. When sunlight strikes a photovoltaic cell made of semiconductor material (primarily silicon), photons transfer energy to electrons in the semiconductor, causing them to undergo transitions, creating a potential difference (voltage) and ultimately generating direct current (DC).
Process:
Illumination: Sunlight strikes the surface of a photovoltaic module (composed of numerous photovoltaic cells encapsulated in a package).
Photoelectric Conversion: The photovoltaic module absorbs sunlight energy and directly converts it into DC electricity.
Energy Convergence: Multiple photovoltaic modules are connected in series or parallel to form a photovoltaic array, generating greater current and voltage. Converting DC to AC: DC is converted to AC that meets grid standards through an inverter.
Boosting and Grid Connection: After the AC voltage is increased by a step-up transformer, it is connected to the public grid or directly distributed to consumers through a substation.
Monitoring and Management: The monitoring system monitors the power plant's operating status (power generation, equipment status, environmental parameters, etc.) in real time to ensure efficient and safe operation.
b) Concentrated Solar Thermal Power Generation:
Core Principle: Uses mirrors or lenses to focus sunlight from a large area onto a small receiver, generating high temperatures.
Process:
Concentrated Solar Energy: A large array of tracking mirrors (heliostats) reflects and focuses sunlight onto a heat sink atop a central tower or onto linear collector tubes.
Heat Conversion: The heat transfer medium (such as molten salt) within the heat sink is heated to a high temperature (up to hundreds of degrees Celsius).
Thermal Power Generation: The high-temperature heat medium heats water through a heat exchanger, converting it into high-temperature, high-pressure steam.
Electricity is generated by steam-driven steam turbines, which in turn drive generators. Thermal Storage (Optional): Some CSP plants are equipped with thermal storage systems such as molten salt, allowing them to generate electricity continuously for several hours after sunset or on cloudy days.
Grid Connection: The boosted AC power is then connected to the grid.
3. Main Types
a) By Scale:
Large-Scale Ground-Based Power Plants: The most common type, typically installed in open wasteland, deserts, and other areas. They can reach capacities of tens of megawatts or even gigawatts, primarily supplying power to the grid.
Commercial and Industrial Rooftop Power Plants: Installed on the rooftops of large buildings such as factories, shopping malls, and warehouses, these plants are of moderate size and primarily serve industrial and commercial users, generating electricity for their own use and feeding surplus power to the grid.
Distributed/Household Rooftop Power Plants: These plants are installed on residential rooftops and are relatively small (typically ranging from a few kilowatts to tens of kilowatts). They primarily meet the electricity needs of households.
Agri-PV/Aquaculture-PV Complementary Power Plants: PV panels are installed above farmland or fish ponds, achieving spatial integration between power generation and agricultural/fishery production. Floating PV Power Plants: PV modules are installed on water surfaces such as reservoirs, lakes, and offshore areas, conserving land resources and potentially reducing evaporation and inhibiting algae growth.
b) By Technology:
PV Power Plants: Based on the aforementioned PV power generation technologies.
Concentrated Solar Thermal Power Plants: Based on the aforementioned CSP technologies (common technologies include trough, tower, Fresnel, and dish).
4. Key Components (Taking Large-Scale PV Power Plants as an Example)
PV Modules: The core unit for energy conversion (commonly known as "solar panels").
Mounting System: The structure that supports and secures PV modules, typically available in fixed or tracking (single-axis/dual-axis trackers) to maximize sunlight absorption.
Inverters are devices that convert the DC power generated by the modules into AC power. Types include centralized inverters, string inverters, and microinverters.
Combiner Boxes/Distribution Cabinets: Aggregate the current from multiple PV strings and provide primary protection.
Step-Up Transformers: Boost the AC voltage output from the inverter to a grid voltage suitable for long-distance transmission. Substations and switchyards: Contain high-voltage switchgear and protective devices, enabling the collection, step-up and step-down, distribution, and protection of electrical energy, ultimately connecting it to the grid.
Monitoring and data acquisition systems: Provide real-time monitoring of the operating status, power generation, and environmental data of all key power plant equipment, enabling remote monitoring, fault diagnosis, and operations management.
Cables: Connect electrical equipment and transmit power and signals.
Lightning protection and grounding systems: Protect power plant equipment and personnel.
Fences and security systems: Ensure the safety of power plant property.
5. Significant Advantages
Clean and renewable: Utilizing the vast solar energy supply, power generation produces no emissions (no pollutants such as CO2, SO2, and NOx, or greenhouse gases, are released during operation).
Resource-rich: Deployable anywhere there is sunlight, particularly suitable for areas with abundant solar resources.
Modular design: Flexible scale, ranging from a few kilowatts for residential applications to gigawatts for large power plants.
Low operation and maintenance costs: The main equipment has no moving parts (non-tracking photovoltaic systems), making maintenance relatively simple. Lowering electricity costs: Due to the maturity of technology and large-scale application, the cost per kilowatt-hour of electricity continues to decline rapidly, now lower than that of traditional fossil fuels in many areas.
Distributed potential: Supporting distributed deployment (rooftop PV) reduces grid transmission losses and improves energy security.
Creating jobs: Numerous employment opportunities are created from equipment manufacturing, project construction, and operations and maintenance.
Multifunctional land use can be integrated with agriculture, fisheries, and other sectors, such as the complementary use of agri-solar and fish-solar systems.
Quiet operation: Operating noise is extremely low (primarily from cooling fans).
Summary: As one of the most promising clean energy technologies, solar power stations are playing an increasingly important role in the global energy transition due to their significant advantages, including environmental friendliness, renewability, and rapidly declining costs. From large-scale ground-mounted power plants to distributed rooftop systems and various innovative application scenarios (such as floating systems and agri-solar hybrids), solar power generation is transforming our energy landscape with unprecedented breadth and depth.
For more information, visit:
http://www.fdjwang.com/
