Solar photovoltaic power generation solutions provide energy saving and emission reduction for telecommunication power supply

In December 2009, the 15th Conference of the Parties to the United Nations Framework Convention on Climate Change was held in Copenhagen, Denmark, and the Copenhagen Accord was issued. According to the agreement, industrialized countries should submit quantified emission targets for 2020 at the economic level to the Secretariat of the Convention before January 31, 2010, and developing countries should submit measures to slow down climate change under the condition of sustainable development.

Energy conservation and emission reduction is a major measure to implement the scientific development concept and build a harmonious society. It is an inevitable choice for building a resource-saving and environmentally friendly society. It is the only way to promote economic structural adjustment and change the growth mode. It is an inevitable requirement for safeguarding the long-term interests of the Chinese nation. my country's "Eleventh Five-Year Plan" outline proposes that the energy consumption per unit of GDP will be reduced by about 20% during the "Eleventh Five-Year Plan" period, and the total emission of major pollutants will be reduced by 10%.

The energy consumption of communication systems has increased year by year. The information industry has become the fifth largest energy-consuming industry in the world, and it is urgent to vigorously promote energy conservation and emission reduction. As early as two years ago, the former Ministry of Information Industry declared that: in terms of the communication industry alone, my country's communication industry consumes more than 20 billion kWh of electricity per year, and has become a high-energy-consuming industry. Paying attention to energy conservation and emission reduction in communication systems will not only help operators save costs, but also achieve a change in growth mode and improve the sustainable development capabilities of enterprises. At the same time, energy conservation and emission reduction is also a social responsibility that operating companies should bear.

Since Chabin and Pirson first developed practical monocrystalline silicon solar cells at Bell Labs in 1954, after more than half a century of development, crystalline silicon solar photovoltaic modules have become mature commercial products. The application of solar photovoltaic power generation in the field of communication power supply has also been explored for many years. Due to the characteristics of solar photovoltaic power generation that is not restricted by geographical location, compared with other "green" energy sources such as wind power generation, solar photovoltaic power generation occupies the most important position in energy conservation and emission reduction in communication systems. ZTE has accumulated rich experience in the application of solar photovoltaic power supply. In the overseas communication projects that have been implemented, the total capacity of solar photovoltaic power generation in operation has exceeded 10 megawatts peak (1 megawatt = 106). In June 2009, ZTE was invited to provide solar photovoltaic power supply solutions for mobile communication base stations at the Shanghai World Expo venues. In line with the principle of maximizing energy conservation and emission reduction and making full use of solar energy resources, the "best utilization" solar photovoltaic power supply solution is specially recommended.

The characteristics of the solar power supply requirements for mobile base stations at the Expo venues are as follows.

*Social benefits need to be considered to minimize annual carbon emissions.

*The amount of solar radiation in Shanghai varies greatly from month to month.

*Base stations in hot communication areas consume more power.

*The module installation method needs to be designed according to the existing building conditions.

*The reliability requirements for communication power supply are particularly high.

The power consumption of communication equipment is shown in Table 1.

The geographical location of Shanghai is 31°13""""48"N, with an average altitude of 7m. The meteorological data are shown in Table 2.

According to the design principle of "optimal utilization" solar photovoltaic power supply solution, the photovoltaic array installation angle is designed according to the maximum solar radiation that can be received throughout the year, maximizing the use of solar energy resources and reducing carbon emissions. The insufficient photovoltaic energy is provided by the mains, ensuring that the base station power supply CAPAX (capital expenditure) and OPAX (operating expenditure) are both minimized. The battery capacity is designed according to the battery backup power supply time of 3 days to extend the battery life and high power supply reliability.

The best tilt angle of the solar array is calculated to be 30° (towards due south). Furthermore, the average daily solar radiation energy at different tilt angles can be plotted as shown in the figure.

Through a series of calculations, the solar photovoltaic module configuration requires 40 175Wp modules and the battery bank is configured with 3 groups of 800AH GEL batteries. Then the solar photovoltaic module capacity configuration verification is carried out.

As can be seen from Figure 2, in the "optimal utilization" solar photovoltaic power supply scheme, the solar photovoltaic power generation just meets the load consumption in the months with the highest solar radiation, while the power generation in other months is not enough to maintain the load power supply. The part of the solar photovoltaic power generation that is not enough for the load power consumption is automatically supplemented by the city power supply through the control of the solar charge and discharge controller in the power supply system. The supplementary power supply from the city power supply only accounts for 8% of the total power consumption of the load, indicating that this scheme has made the most of the solar photovoltaic power generation capacity. Solar photovoltaic power generation provides 8488.3kWh of power for the load throughout the year. According to the average carbon emission of 0.785kg/kWh per unit of power generation, CO2 emissions can be reduced by about 6700kg each year, which is equivalent to reducing the burning of about 4800kg of coal.