I. Introduction
With the continuous deterioration of the global environment and the depletion of fossil energy, countries around the world are looking for new energy sources suitable for human survival and development. The construction of photovoltaic energy storage projects is an important measure to implement energy transformation at the moment. Photovoltaics is actually an abbreviation for the use of solar power generation systems. It has unique advantages and is one of the most promising power generation technologies at present. Because solar energy is ubiquitous, there is no need to consider the source of raw materials when using it to generate electricity. Greatly improved the efficiency of power development.
Photovoltaics is a new power generation system that uses the photovoltaic effect of solar cell semiconductor materials to convert solar radiation into electrical energy. It has two modes of independent operation and grid-connected operation. The grid-connected photovoltaic power generation system mainly refers to photovoltaic systems that are connected to the grid and accept grid dispatching, such as centralized photovoltaic power plants and distributed photovoltaic power plants. Independently operating photovoltaic power generation systems refer to various photovoltaic power generation systems that exist independently of the power grid, such as photovoltaic power supplies and solar street lights. As for photovoltaic energy storage, in fact, it refers to a photovoltaic system using a battery as an energy storage device, which can provide a better environment for people to use electricity and improve people's quality of life.
Photovoltaic energy storage mainly includes grid-connected photovoltaic energy storage systems and stand-alone photovoltaic energy storage systems. 1. The advantage of grid-connected photovoltaic energy storage systems is that photovoltaic power can be applied regardless of day or night. Generally, distributed metering is used during the day, and the power of the power grid is still used at night. The energy stored in the energy storage device can discharge the energy storage system. Grid-connected photovoltaic power generation systems are usually directly connected to the power grid and directly input power into the power grid. Due to the inadequate energy storage system, there may be a phenomenon of abandonment of light and electricity, which affects the power output of the photovoltaic power generation system due to external factors. Large, it is not conducive to the promotion of renewable energy. If a suitable energy storage system is configured in the grid-connected photovoltaic system in the future, it can become an important direction for photovoltaic energy storage to expand the production scale; 2. Independent photovoltaic energy storage system, which is Refers to a photovoltaic system that operates independently without being connected to the power grid. Compared to a grid-connected photovoltaic system, its photovoltaic power output and the dissipation of charge load are not in the same time period. It can be installed at any time as long as there is sunlight. More convenient and practical.
In order to improve the global environment, support for the photovoltaic industry in various countries is gradually increasing. Especially in 2019, China has not yet started a large-scale photovoltaic installation market, but overseas markets have already begun since the beginning of the year. The total installed capacity in the international market in 2019 is expected to exceed 2018, and it is firmly believed that the global new photovoltaic installed capacity in 2019 will also be more than in 2018. At the end of 2018, the European Commission formulated the “Strategic Long-term Vision for the European Union 2050” and achieved 20% of the overall plan for renewable energy by 2020, striving to achieve zero carbon emissions in 2050 and 50% of energy consumption in 2005. The target of power terminal energy share doubled. Among them, EU countries will target renewable energy to 32% of total energy by 2030. EU member states have responded to the policy call and strived to have a higher installed capacity of new energy in the EU market. Taking Spain as an example, it approved the National Energy and Climate Comprehensive Plan from 2021 to 2030, and plans to increase its installed capacity of renewable energy to 120GW in 2030, and it is mainly derived from photovoltaics and wind power. According to the content of the plan, the Spanish country is expected to reach 8.409GW of photovoltaic installed capacity in 2020. By 2030, 74% of electricity will come from renewable sources, accounting for 41% of total energy, and the total installed capacity of photovoltaics will be increased to 50GW by 2050. In addition, Spain also plans to increase energy storage projects to 6GW, thereby promoting the construction of photovoltaic energy storage projects [1].
(II) Photovoltaic Module Market
Since November 2018, China has begun to implement anti-dumping measures and countervailing measures for solar polysilicon imported from the European Union. As a result, Germany replaced South Korea as the country of origin of China's polysilicon imports, and the number of imports with South Korea fell by 37.6% year-on-year. The global photovoltaic market is becoming more diversified, but the concentration of its module exports is declining. Affected by the domestic and trade friction events in the United States and India, China ’s PV module export market in the first quarter of 2019 turned from traditional markets to emerging countries such as Ukraine, Pakistan, and Vietnam Market, of which the top five global component export markets accounted for 52% of total exports, a decrease of 10% compared to 2013 [2]. Affected by the "Made in India" policy, China's exports to India have dropped significantly. The latest news released by India New Energy and MNRE requires that renewable energy should give priority to "Made in India" products when implementing national policies, and 100% of the modules required for grid-connected photovoltaic projects developed by central ministries and central utilities must be used. Local manufacturing, which will seriously reduce the returns of Indian investment projects and some projects will be delayed. As China ’s exports to the United States are decreasing, it has increased the rate of export to emerging markets such as Japan. The new law implemented in the Japanese market indicates that the grid connection period for unbuilt projects is limited to September 2020, and other emerging markets will drive the development of photovoltaic products in China.
(Three) photovoltaic industry chain
The industrial chain of the photovoltaic industry is mainly composed of crystalline silicon raw material production, silicon rod production, solar cell manufacturing, module packaging, photovoltaic product production, photovoltaic power generation systems and other links, among which solar cells are the most important production link. According to the internal materials of solar cells, they can be divided into crystalline silicon cells, organic polymer cells, thin-film cells, and new-generation solar cells. The conversion efficiency of solar cells actually refers to the percentage obtained when the maximum output power is divided by the solar intensity and multiplied by the light absorption area of ??the solar panel when the irradiation intensity is 1000M / cm3 and the solar temperature is about 25 ° C. According to the relevant requirements in the "Specification Conditions for the Photovoltaic Manufacturing Industry", the minimum conversion rates for polycrystalline silicon cells and single crystal silicon cells must not be less than 16% and 16.8%, respectively. In recent years, the global photovoltaic solar cell conversion rate has been increasing. On the contrary, prices are falling at an average rate of 0.3 yuan / piece / month [3]. The total investment cost of photovoltaic systems is 5 yuan / W. According to the current development trend, it is believed that the era of "parity on-grid" for photovoltaic power generation will soon come.
(Iv) Competition in the photovoltaic industry
The global photovoltaic industry itself is a high-density and high-value-added industry. However, due to the lack of core technologies, the development of China's photovoltaic industry generally relies on overseas technologies to develop. The market for products is often homogenized. According to the latest news, BYD will start a new energy photovoltaic energy storage project in Mexico. It will build a 100MWh photovoltaic energy storage system in Mexico. For Mexico, such a large amount of electricity is equivalent to the daily electricity consumption of 30,000 user households. Mexico According to the CEO of the Energy Fund, in order to maximize the environmental benefits of renewable energy through cooperation with BYD, 240MW solar power stations equipped with a complete energy storage system will be built in the next two years.
Development prospects of overseas photovoltaic energy storage projects
(A) favorable factors
Policy support
The construction of photovoltaic energy storage projects has received significant national support, and the development of the photovoltaic industry will inevitably have broad application space. At present, developed countries such as the European Union have successively introduced policies that regard solar power generation as an important part of renewable energy, and have formulated corresponding strategic plans to promote the development of solar power generation and the photovoltaic industry. It is believed that China will also adopt relevant countermeasures in the near future. Construction of photovoltaic energy storage projects. From the perspective of long-term development, the overseas photovoltaic market has developed tremendously, especially in countries with relatively developed economies and strong awareness of green energy applications, which have taken the construction of photovoltaic energy storage projects as a strategic goal. For example, Portugal, due to the country's relatively good heating conditions, and sunshine hours of up to 2,200 hours / year, the Portuguese government attaches great importance to the development of the photovoltaic power generation industry, and has therefore formulated a FIT strategy to ensure that its total installed capacity of photovoltaics continues to rise. According to the Portuguese APREN data, in 2017, Portugal's renewable energy power generation accounted for 44% of the total local power consumption, and its photovoltaic power generation accounted for a small proportion of the total power generation in Portugal, which means that it has huge development The potential, in the future development will certainly occupy a certain position in the overseas photovoltaic market.
2. Economic development
With the development of the global economy, problems such as energy shortages and environmental pollution have become increasingly serious. In order to properly solve these problems, domestic and foreign countries have begun to look for green energy sources and improve environmental problems. Traditional thermal power generation has been unable to meet global demand. Industrial manufacturing and town construction in various countries are also constantly improving their own construction levels to avoid placing a greater burden on the environment. And expanding the photovoltaic market at home and abroad has become an inevitable trend for the development of renewable energy in the future. Take the United States as an example. As the world's largest energy consuming country, in recent years, its dependence on foreign energy has gradually decreased, and its energy production and consumption structure has also undergone tremendous changes. According to statistics, in the United States' total energy consumption in 2012, oil accounted for 34.7%, coal accounted for 17.4%, natural gas accounted for 26%, nuclear energy accounted for 8.05%, and solar energy accounted for 0.235%, but the first three energy sources are expected to decrease in 2035. To 77%, although the construction scale of the US photovoltaic energy storage projects is still very small, but its development speed is accelerating. In the near future, it will effectively replace non-renewable energy as the green energy base in the total energy.
(B) adverse factors
Economic fluctuation
There are two types of photovoltaic energy storage systems, centralized and distributed, but the growth rate of distributed photovoltaics is significantly higher than that of centralized photovoltaics. And because of the small scale of distributed photovoltaics, fewer construction procedures, short cycles, and The ability to dissipate is strong, so in the future development, the construction of new photovoltaic energy storage projects will mostly focus on distributed photovoltaics. Affected by the global economic fluctuations, especially the US trade blockade policy and the European debt crisis, the anti-globalization wave has continued to strike, which will cause the industrial structure of some developing countries to be affected. The goal for the introduction of photovoltaic energy storage system technology It is also affected, which is not conducive to the global promotion of photovoltaic power generation systems. This requires each country to strengthen the photovoltaic industry in accordance with the actual situation, promote the development of the industry, and accelerate the construction of photovoltaic energy storage projects without being affected by the international background.
2. tight time
Due to the different economic policies of overseas countries and the time required for energy transition, coupled with the uneven level of R & D technology in the local photovoltaic industry, it has not been possible to achieve unified development of overseas photovoltaic energy storage project construction, and even some countries have not The over-strength talent team implements photovoltaic construction, which also poses a challenge to photovoltaic power generation instead of fossil energy power generation. Therefore, it is necessary for overseas countries to continue to learn, improve the level of photovoltaic technology, and make their own contributions to global environmental protection. In addition, since the photovoltaic industry has made less profits, it needs to be innovative to achieve the national energy transition.
V. Conclusion
In summary, photovoltaic energy storage projects are indeed an important foundation for countries at home and abroad to build a "resource-saving and environment-friendly" society. Only by promoting the development of the photovoltaic industry can we further improve the purification of the global environment. Therefore, for overseas photovoltaic The development of energy storage projects has bright development prospects, and relevant personnel are required to continuously improve their deficiencies. Under the positive influence of factors, work hard to use green energy to drive economic development.