Foreword With the advancement of science and technology and human civilization, "coexisting with the environment" has become an increasingly important concept for modern humans. Environmental and resource issues are now before us, requiring everyone's consideration and solutions. Global environmental problems include the greenhouse effect, acid rain, ozone layer depletion, hazardous waste, marine pollution, deforestation, desertification, and changes in the natural food chain. Among these, the most important issue is preventing the greenhouse effect and controlling the emission of polluting gases such as CO, NO, and SO. The most direct method is to use green and environmentally friendly products to build our home. In China, the main sectors contributing to greenhouse gas emissions are the chemical industry (such as chemical plants and fertilizer plants), energy conversion sectors (such as thermal power plants), and the transportation sector (such as vehicle exhaust). To address this, relevant units and departments have taken many measures from both the generation and control perspectives, such as ensuring vehicle exhaust emissions meet standards, desulfurizing and dephosphorizing exhaust gases, and using high-efficiency energy-saving products. Global energy resource issues: The proven exploitable reserves of major chemical fuels such as oil, natural gas, and uranium have only been explored for half a century. The effective utilization of these resources and the search for new energy sources have become urgent issues. The global resource issue is the search for safe, pollution-free, and renewable green energy sources, such as solar, wind, ocean, and geothermal energy, to replace chemical fuels in power generation. Solar power generation systems are tangible technological, green, and human-centered products. Because they use green and renewable energy—solar energy—they produce no harmful gases or substances, making them truly green and environmentally friendly products. Solar Power Generation System Composition Solar power generation systems are high-tech products integrating multiple disciplines such as physics, chemistry, electronics, electrical engineering, optics, mechanical engineering, optoelectronics, and systems engineering. The solar energy conversion to electricity utilizes physics, chemistry, and optoelectronics. Specialized processes are used to treat silicon atomic materials at high temperatures (approximately 1500℃) and crystallize them, then precision-cut them into crystal wafers. Suitable chemical agents are added to produce solar cell wafers. The crystal structure must conform to the wavelength range encompassed by the solar spectrum and generate sufficient photoelectron flow to form an electromagnetic field, producing a certain voltage and current. The power controller for a solar power generation system uses polycrystalline silicon, which has lower conversion efficiency than monocrystalline silicon but is cheaper. Solar power generation systems are integrated with building structures and urban landscapes. Utilizing the shape of solar cells, they harmonize with the surrounding environment, creating landscape highlights that combine practicality, aesthetics, science education, technology, humanism, and environmental friendliness. A solar power generation system consists of solar cell arrays, a solar controller, and batteries (or battery banks). 1) Solar Cell Arrays: Solar panels are the core and most valuable part of a solar power generation system. Their function is to convert solar radiation into electrical energy, either storing it in batteries or powering loads. The quality and cost of the solar panels directly determine the quality and cost of the entire system. 2) Solar Controller: The solar controller controls the operating status of the entire system and provides overcharge and over-discharge protection for the batteries. In areas with large temperature differences, a qualified controller should also have temperature compensation functionality. Other additional functions, such as light-controlled switches and time-controlled switches, should be optional features. 3) Batteries: Lead-acid batteries are generally used. In small-scale systems, nickel-metal hydride, nickel-cadmium, or lithium batteries can also be used. Their function is to store the electrical energy generated by the solar panels when there is sunlight and release it when needed. 4) Inverters: Since the direct output of solar energy is generally 12VDC, 24VDC, or 48VDC, a DC-AC inverter is needed to convert the DC power generated by the solar power system into AC power in order to provide power to 220VAC appliances. In some cases, when multiple voltage loads are required, a DC-DC inverter is also used, such as converting 24VDC power into 5VDC power. Solar Power System Classification: 1) Based on the type of power supplied, solar power systems can be divided into three categories: DC power supply systems (see Figure 1), AC power supply systems (see Figures 2 and 3), and AC/DC power supply systems (see Figure 4). 2) Based on system composition or energy acquisition method, solar power systems can be divided into photovoltaic power supply systems (see Figure 3), wind power generation systems, and wind-solar hybrid power supply systems (see Figure 4). 3) Based on different system operating modes, solar power systems can be divided into stand-alone systems and grid-connected power generation systems. 1) For stand-alone systems, excess solar power generated during the day is stored in batteries to meet nighttime electricity demand and also serves as backup power during disasters. The operation of a stand-alone solar power system is as follows: ① During the day, solar energy is converted into electrical energy by solar cells. This electrical energy is then converted by a power regulator to supply power to the load, while simultaneously being stored in batteries. ② At night or in severe weather conditions, the electrical energy stored in the batteries is automatically supplied to the load via the power regulator. 2) For grid-connected systems, solar power generated during the day can be fed back to the grid for use at night, with any shortfall supplied by the grid. The operation of a grid-connected solar power system is as follows: ① Under normal conditions: Solar energy is converted into electrical energy by solar cells. This electrical energy is then converted by a power regulator to supply power to the load. When load demand is low, excess generated energy can be fed back to the grid for sale. When load demand is high, such as at night or in severe weather conditions, any shortfall is automatically supplied from the grid. ② During grid outages: When grid power fails, the power regulator automatically stops operating, and the load stops receiving power from the grid. Calculation of power generation of solar power generation system and its contribution to the environment (1) Based on the location where solar cells can be installed in the building and the investment in equipment, the form and capacity of the solar power generation system are determined. In order to ensure the advancement of technology and products, the future parallel expansion function and interface are considered when designing and selecting. The power generation of the solar power generation system is related to the solar radiation, the number of solar cell modules, the output of solar cell modules, radiation intensity and other factors of the region. The calculation formula is as follows: Annual power generation of solar power generation system Where, KW•h is the power generation (KW h); U is the solar radiation (KW•h/me day block); P is the output of solar cell module (W/block); P is the number of solar cell modules (blocks); H is the solar cell panel parameter; H is the power regulator efficiency; H is the line loss coefficient. (2) Engineering example of solar power generation system 1) Calculation conditions Taking a certain project in Beijing as an example: Latitude 39°56'N: Longitude 116°17'E; Altitude 30m: Azimuth 0° South, Inclination 0°. The solar cell array outputs 302.4 kW, and the modules output 120 W. The number of modules is 2520. The solar panel parameters are 0.95, the power regulator efficiency is 0.90, and the line loss factor is 0.98. 2) The attached table is a comparison of solar power generation systems (3) Evaluation of the environmental contribution of solar power generation systems 1) Power generation of solar power generation systems The design life of solar power generation systems is more than 20 years, so the power generation of a 300kW system is: 20x391742.18=7834843.6 kW•h, which is equivalent to 7834843.6X0.4029X10 =3156.66t of standard coal 2) CO emission reduction The CO emission reduction is 726x315566=2291t Note: According to the statistics of the power sector: ① CO emission is about 726kg/t of standard coal; ② SO emission is about 22kg/t of standard coal; ③ NOx emission is about 10lg/t of standard coal; ④ Soot emission is 17kg/t of standard coal. 3) SO2 emission reduction: SO2 emissions reduced by 22 x 3155.66 = 69.42 t. 4) NOx emission reduction: NOx emissions reduced by 10 x 3155.66 = 31.56 t. 5) Particulate matter emission reduction: Particulate matter emissions reduced by 17 x 3155.66 - 53.65 t. 6) Resource reduction: Resource reduction is calculated based on petroleum. ① Conversion of petroleum combustion calorific value to electricity: 418 x 10 J / 3600 Wh/kcal = 1.16 Wh/kcal; 1 kcal = 4.18 x 10 J. ② Converted to petroleum combustion at power plants: Power plant output = petroleum calorific value × conversion value × power plant to user efficiency = 10740 kcal/kg x 1.16 Wh/kcal x 0.37 = 4.61 kWh/kg. ③ The amount of petroleum resources that can be reduced can save petroleum. 834 843.6 Kw•h / 4.6l kW•h/kg = 1 7 x 10 kg This shows that solar power systems, while converting light energy into electrical energy, do not produce pollutants like CO2 or acidic compounds that cause air pollution, unlike thermal power plants. They also do not generate vibration or noise pollution. The emission of the greenhouse gas carbon dioxide has been fully considered in the engineering construction. Compared with fossil fuel combustion, solar power systems are green and do not produce pollutants. Therefore, the introduction of solar power systems will have an environmental protection effect. At the same time, the electricity generated by solar power systems saves the fossil fuel consumption of power plants and also saves fossil resources used as raw materials in industries. Conclusion Green energy and sustainable development are major challenges facing humanity this century. Developing new energy sources and making full and rational use of existing energy sources have received significant attention from governments worldwide. Solar power, as a clean and environmentally friendly energy source that is inexhaustible, will experience unprecedented development. With the deepening of the solar energy industry's industrialization and technological development, its efficiency and cost-effectiveness will improve, leading to its widespread application and greatly promoting the rapid development of solar power technology in China. (Article excerpted from "Energy Saving Innovation 2006 – Proceedings of the First National Electrical Energy Saving Competition")