Photovoltaic grid-connected system
The biggest feature of the solar photovoltaic grid-connected system is that the DC power generated by the photovoltaic array is converted into AC power that meets the requirements of the mains grid by the grid-connected inverter, and then directly connected to the mains network. Outside the load, the excess power is fed back to the grid.
This type of system is usually able to use city electricity and solar photovoltaic module arrays in parallel as the power source for local AC loads. Reduce the load shortage rate of the entire system. And the grid-connected PV system can play a role in peak regulation of the public grid.
Solar photovoltaic effect, abbreviated as photovoltaic (PV), also known as photovoltaic effect (Photovoltaic), refers to the phenomenon of uneven semiconductor or a combination of semiconductor and metal when there is a potential difference.
Photovoltaics is defined as the direct conversion of ray energy. In practical applications, it usually refers to the conversion of solar energy to electrical energy, that is, solar photovoltaic. Its realization is mainly through the use of solar panels made of silicon and other semiconductor materials, and the use of light to generate direct current, such as solar cells that can be seen everywhere in our daily lives.
Photovoltaic technology has many advantages: for example, it does not have any mechanical operating parts; it does not need any other "fuel" except sunlight, and it can work under direct and oblique sunlight; and it is very convenient and flexible in terms of site selection. , The roofs and open spaces in the city can be used. Since 1958, the solar photovoltaic effect has been applied for the first time in the field of energy supply for space satellites in the form of solar cells. Today, from the power supply of automatic parking meters and solar panels on the roof to the large solar power centers, their applications in the field of power generation have spread all over the world.
Solar energy is a rapidly growing form of energy, and the solar energy market has also made considerable progress in the past decade. According to data, calculated on the basis of the annual average solar system installed capacity, the global solar market has a compound annual growth rate of 47.4%, from 598MW in 2003 to 2826MW in 2007. It is predicted that by 2012, the average annual solar system installed capacity may further increase to 9,917MW, and the sales of the entire solar energy industry may increase from US$17.2 billion in 2007 to US$39.5 billion in 2012. This growth momentum is largely attributable to the rapidly increasing global market demand, increasing feed-in tariffs and various government incentives.
In some major countries in the world, especially Germany, Italy, Spain, the United States, France and South Korea, the federal government, state governments and local government agencies have provided tax rebates, tax credits and other incentives to end users of solar products. , Distributors, system integrators and manufacturers provide subsidies and economic incentives to promote the use of solar energy in grid-connected applications and reduce dependence on other energy sources. However, traditional public power companies with huge political lobbying power may also try to change the relevant legislation in their markets, which may also have a relatively negative impact on the development and commercial applications of solar energy.
But generally speaking, due to the political and economic instability in many oil and gas producing regions around the world, governments of many countries are taking active measures to reduce their dependence on foreign energy. Solar energy provides a very attractive power generation program, and does not form a serious dependence on foreign energy. In addition, the increasingly prominent environmental issues and the risks of climate change associated with fossil fuel power generation have formed political motivations, prompting the government to implement greenhouse gas emission reduction strategies aimed at reducing carbon dioxide and other gas emissions. Solar energy and other renewable energy sources help solve these environmental problems.
Governments around the world have implemented a variety of incentive policies to promote the development and application of solar energy and other renewable energy. Many European countries, some Asian countries, many states and provinces in Australia, Canada and the United States, and some Latin American countries have promulgated renewable energy policies. Customer-centric financial incentives include capital cost tax rebates, mandatory photovoltaic feed-in tariffs and tax credits. The capital cost tax rebate policy provides a fund to offset the consumer's initial investment in solar energy systems. The mandatory photovoltaic feed-in tariff policy requires that public power companies pay users for the electricity they generate through solar systems based on the kilowatt-hours generated, and the price is guaranteed for a certain period of time. These have encouraged the development of the photovoltaic industry.
In my country, the bottleneck problem that has long plagued the development of my country's photovoltaic industry, that is, the problem of raw materials and markets overseas in the industrial chain structure has also received policy support. In the first half of the year, major changes in the policies of European countries, especially Spain, in the field of solar energy caused the global photovoltaic market to shrink sharply, which in turn led to generally unsatisfactory operating conditions for global photovoltaic companies in the first quarter. In order to reverse this situation, my country is determined to launch a large number of photovoltaic power generation projects, solve the "sales market" problem, stabilize the domestic demand of the photovoltaic industry to a large extent, and gradually form rational output expectations. Some time ago, the Ministry of Finance also formulated the "Implementation Opinions on Accelerating the Application of Solar Photovoltaic Buildings" and the "Interim Measures for the Management of Financial Subsidy Funds for the Application of Solar Photovoltaic Buildings." The "Opinions" have formed two major positive messages for the solar energy industry. The first is the support of industrial policies. The central government not only arranges special funds, but also subsidizes qualified photovoltaic building application demonstration projects to partially compensate for the initial investment in photovoltaic applications. Moreover, regions that have introduced relevant fiscal and taxation support policies will be given priority to receive central financial support. The second is that the "Solar Roof Plan" stimulates downstream demand, etc., may form relatively optimistic expectations, that is, expand the development space of the solar energy industry, and downstream demand will definitely improve.