5 degrees to 10 degrees; When the latitude is equal to 4 1 degree to 55 degrees, the power generation angle is equal to latitude plus 10 degrees to 15 degrees; When the latitude is greater than 55 degrees.
The power generation angle is equal to latitude plus 15 degrees to 20 degrees.
First, photovoltaic power generation:
1, definition:
Photovoltaic power generation is a technology that directly converts light energy into electric energy by using photovoltaic effect of semiconductor interface. It is mainly composed of solar panels (components), controllers and inverters, and the main components are composed of electronic components. After the solar cells are connected in series, they can be packaged and protected to form a large-area solar cell module, and then form a photovoltaic power generation device with power controllers and other components.
2. Principles:
The main principle of photovoltaic power generation is the photoelectric effect of semiconductors. When a photon irradiates a metal, its energy can be completely absorbed by an electron in the metal. The energy absorbed by electrons is large enough to overcome the gravity inside the metal and escape from the metal surface to become photoelectrons.
Silicon atoms have four outer electrons. If pure silicon is doped with atoms with five outer electrons, such as phosphorus atoms, it becomes an N-type semiconductor. If pure silicon is doped with atoms with three outer electrons, such as boron atoms, a P-type semiconductor is formed. When P-type and N-type are combined, the contact surface will form a potential difference, which will become a solar cell. When sunlight strikes the P-N junction, holes move from the P-pole region to the N-pole region, and electrons move from the N-pole region to the P-pole region, forming a current.
Photoelectric effect is a phenomenon that light causes potential difference between heterogeneous semiconductor or different parts of semiconductor and metal. First of all, it is a process from photons (light waves) to electrons, and from light energy to electric energy. Secondly, it is the process of forming voltage.
Polycrystalline silicon is made into silicon wafer to be processed through ingot casting, ingot breaking and slicing. Doping and diffusing trace amounts of boron, phosphorus, etc. On the silicon wafer, the schematic diagram of photovoltaic power generation forms a pn junction. Then, the prepared silver paste is printed on the silicon wafer by screen printing to make grid lines, and then the back electrode is made at the same time after sintering, and a layer of antireflection coating is coated on the surface with grid lines to make the battery chip. When the battery pieces are arranged and combined into a battery assembly, a large circuit board is formed.
Generally speaking, the assembly is surrounded by an aluminum frame, the front side is covered with glass, and the back side is equipped with electrodes. Together with battery components and other auxiliary equipment, a power generation system can be formed. In order to convert direct current into alternating current, a converter needs to be installed. After power generation, it can be stored in storage battery or input into public power grid. In the cost of power generation system, battery components account for about 50%, and current converter, installation fee and other auxiliary components account for another 50%.
3. Features:
① Advantages:
Compared with the commonly used thermal power generation system, the advantages of photovoltaic power generation are mainly reflected in:
(1) there is no danger of failure;
(2) Safe and reliable, without noise and pollution discharge, absolutely clean (pollution-free);
(3) Not limited by the geographical distribution of resources, the advantages of building roofs can be utilized; For example, areas without electricity and areas with complex terrain;
(4) local power generation and power supply can be realized without consuming fuel and erecting transmission lines;
⑤ High energy quality;
⑥ Users are easy to accept emotionally;
⑦ The construction period is short, and the time required for obtaining energy is short.
② Disadvantages:
(1) irradiation has a small energy distribution density, which means it will occupy a huge area;
(2) The energy obtained is related to meteorological conditions such as four seasons, day and night, sunny and rainy.
③ At present, compared with thermal power generation, the opportunity cost of power generation is higher.
④ Photovoltaic panels are not environmentally friendly in the manufacturing process.
4. Conversion rate:
(1), monocrystalline silicon:
Mass production conversion rate:19.8-21%; Mainly in
17.5%。 At present, it is unlikely that the technological breakthrough will increase by more than 30%.
② Gallium arsenide:
The conversion rate of GaAs solar cells is relatively high, about 23%. But it is expensive, and it is mostly used in important places such as aerospace. There is basically no practical value of large-scale industrialization.
③ Film:
Thin film photovoltaic cells have the advantages of portability, light weight and good flexibility, and are widely used, especially suitable for photovoltaic building integration. If the efficiency of thin-film battery module is almost the same as that of crystalline silicon battery, its cost performance will be unparalleled. Thin-film batteries prepared on flexible substrates have many advantages, such as being able to be curled and folded, not bumping and bumping, light weight, good weak light performance, etc., and their future application prospects will be broader. At present, the conversion rate of amorphous silicon thin films is about 9%.
④ Efficiency attenuation:
After the crystalline silicon photovoltaic module is installed, it will be exposed to the sun for 50- 100 days, and the efficiency will be reduced by about 2-3%. After that, the attenuation will be greatly reduced and stabilized at 0.5-0.8% per year, and about 20% after 20 years. The attenuation of single crystal module is less than that of polycrystalline module. The attenuation of amorphous optical elements is lower than that of crystalline silicon.
5. Development process:
Since the 1970s, with the development of modern industry, the global energy crisis and air pollution problems have become increasingly prominent, and the traditional fuel energy has been decreasing, which is increasingly harmful to the environment. At the same time, about 2 billion people around the world have no access to normal energy supply. At this time, the whole world has turned its attention to renewable energy, hoping that renewable energy can change the energy structure of human beings and maintain long-term sustainable development.
After 1990s, photovoltaic power generation developed rapidly. By 2006, more than 65,438+00 MW photovoltaic power generation systems and 6 MW interconnected photovoltaic power stations have been built in the world. The United States is the first country to make a development plan for photovoltaic power generation. 1997 put forward the plan of "one million roofs". Japan launched the new sunshine plan on 1992. By 2003, Japan's photovoltaic module production accounted for 50% of the world's total, and four of the top 10 manufacturers in the world were in Japan. However, Germany's new renewable energy law stipulates the on-grid tariff of photovoltaic power generation, which greatly promotes the development of photovoltaic market and industry, making Germany the fastest developing country in the world after Japan. Switzerland, France, Italy, Spain, Finland and other countries have also formulated photovoltaic development plans, invested huge sums of money in technology development and accelerated industrialization.
20 1 1 year, the global installed photovoltaic capacity is about 27.5GW, which is as high as 52% higher than the previous year's18./GW, and the global cumulative installed photovoltaic capacity exceeds 67GW. Of the total installed capacity of nearly 28GW in the world, nearly 20GW of systems have been installed in Europe, but the growth rate is relatively slow. The Italian and German markets account for 55% of the global installed capacity growth, 7.6GW and 7.5GW respectively. 20 1 1 year, the market demand of photovoltaic industry in the Asia-Pacific region, represented by China, Japan and India, increased by 129% year-on-year, with installed capacity of 2.2GW, 1. 1GW and 350MW respectively. In addition, in the increasingly mature North American market, the newly added installed capacity is about 2. 1GW, up 84% year-on-year.
In the next decade, the photovoltaic power generation market in China will change from independent power generation system to grid-connected power generation system, including desert power station and urban roof power generation system. China solar photovoltaic power station has great potential. With the support of active and stable policies, by 2030, the installed photovoltaic capacity will reach 654.38+0 billion kilowatts, and the annual power generation will reach 654.38+0.3 billion kWh, which is equivalent to building less than 30 large coal-fired power plants. In the next three years, the state will invest 20 billion yuan to subsidize the photovoltaic industry, and China solar photovoltaic power generation will usher in a new round of rapid growth, attracting more strategic investors to integrate into this industry.
6, system classification:
① Independent photovoltaic power generation:
Independent photovoltaic power generation is also called off-grid photovoltaic power generation. It is mainly composed of solar cell module, controller and storage battery. In order to supply power to AC load, it is necessary to configure AC inverter. Independent photovoltaic power stations include village power supply system, solar household power supply system, communication signal power supply, cathodic protection, solar street lamps and other photovoltaic power generation systems with batteries that can operate independently.
② Grid-connected photovoltaic power generation:
Grid-connected photovoltaic power generation means that the direct current generated by solar module is converted into alternating current meeting the requirements of public power grid through grid-connected inverter, and then directly connected to public power grid. Examples of photovoltaic power generation can be divided into grid-connected power generation systems with and without batteries.
③ Distributed photovoltaic power generation:
Distributed photovoltaic power generation system, also known as distributed power generation or distributed energy supply, refers to the configuration of small photovoltaic power supply system near the user site or power consumption site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet both requirements.
7. Structural composition:
Photovoltaic power generation system consists of solar cell array, storage battery, charge and discharge controller, inverter, AC distribution cabinet, sun tracking control system and other equipment.
8. Application areas:
(1), solar power supply for users: (1) 10 ~ 100 W, which is used for military and civilian life in remote areas without electricity, such as plateaus, islands, pastoral areas, border posts, etc. , such as lighting, TV, tape recorder, etc. (2)3-5KW household roof grid-connected power generation system; (3) Photovoltaic water pump: to solve drinking and deep well irrigation in areas without electricity.
(2) Traffic field, such as navigation lights, traffic/railway signal lights, traffic warning/sign lights, Yuxiang street lights, overhead obstacle lights, highway/railway wireless telephone booths, unattended power supplies, etc.
(3) Communication/communication field: solar unattended microwave relay station, optical cable maintenance station, broadcasting/communication/paging power supply system; Rural carrier telephone photovoltaic system, small communication machine, soldier GPS power supply, etc.
(4) Petroleum, marine and meteorological fields: cathodic protection solar power supply system for oil pipelines and reservoir gates, life and emergency power supply for oil drilling platforms, marine detection equipment, meteorological/hydrological observation equipment, etc.
(5) Power supply for household lamps: such as courtyard lamps, street lamps, portable lamps, camping lamps, mountaineering lamps, fishing lamps, black lamps, rubber tapping lamps, energy-saving lamps, etc.
(6) Photovoltaic power stations: 10KW-50MW independent photovoltaic power stations, wind and light (diesel) complementary power stations, various large parking lot charging stations, etc.
(7) Solar building combines solar power generation with building materials, so that large-scale buildings in the future can achieve self-sufficiency in electricity, which is a major development direction in the future.
(8) Matching with automobiles: solar car/electric car, battery charging equipment, automobile air conditioner, ventilator, cold drink box, etc.
(9) Solar hydrogen production and fuel cell regeneration power generation system.
(10) power supply for seawater desalination equipment.
(1 1) satellites, spacecraft, space solar power stations, etc.