1.1 The general trend of new energy has been set, and the energy storage industry is rising

New energy generation is unstable, and the demand for energy storage arises. The power system needs to maintain a dynamic balance, and when the power generation is too high, the electric energy needs to be converted into chemical energy or potential energy and other forms of energy to be stored. In the traditional energy era, coal power is controllable and can achieve stable regulation of the power grid, so the importance of energy storage has not been shown. With the advent of the era of the energy revolution, and the continuous popularization of new energy such as scenery power generation, the power supply is affected by uncertain factors such as climate and geographical location, and it is difficult to maintain the balance of supply and demand at any time under the original power grid system, so energy storage has become an indispensable part of the new energy power grid system. Pumped storage is currently the main energy storage and new energy storage is developing rapidly. From the perspective of energy storage structure, both global energy storage and China's energy storage structure are based on pumped storage, accounting for 86.2%/86.3%, respectively. However, pumped storage is limited by geographical location, and pumped storage converts potential energy into mechanical energy and then into electrical energy with a long response time, so a new type of energy storage with a fast response time and small limitations is gradually developed.

Electrochemical energy storage is the mainstream new energy storage, and Chinese suppliers lead the market. Electrochemical energy storage technology has the characteristics of high energy density, large operating voltage, long cycle life, fast charging speed, etc., so it occupies the mainstream position, and lithium batteries with leading safety, high efficiency, long cycle, and other advantages, the application proportion has risen year by year, and has stabilized between 80% and 95% in the past five years. With the international leading lithium battery industry, Chinese suppliers have increased their share in the energy storage market, and 2020, they have overtaken South Korea to become the world's largest supplier, accounting for 69%, and their leading advantage is deepening.

1.2 Household storage demand is stabilizing, and the trend of all-in-one machines is emerging

Diverse application scenarios and stable household requirements. From the perspective of the entire power system, the application scenarios of energy storage can be divided into three major scenarios: power generation side energy storage, transmission and distribution side energy storage, and power side energy storage. The application of power generation and transmission and distribution side mainly focuses on the power grid, and energy storage is often used for power peak regulation, system frequency regulation, grid connection of renewable energy, and alleviating grid congestion, delaying the expansion and upgrading of transmission and distribution equipment. The demand users of the power side scenario are generally households, industry and commerce, and public institutions. The energy storage system is mainly used for economic needs such as self-use of electricity, peak-valley price spread arbitrage, capacity, and electricity charge management, and improving the reliability of power supply. According to BNEF statistics, in global energy storage applications, household demand is stable at 20%-30%, much higher than that of industry and commerce. Household energy storage profit model: cooperate with photovoltaic, increase the proportion of photovoltaic self-use, peak valley spread arbitrage. Household energy storage is generally used with rooftop photovoltaic, there are three main profit models: self-use, surplus online: the policy of the early FIT price is higher than the price of household electricity, "benchmark price, full online" to promote rooftop photovoltaic installed capacity. With the increase in household electricity and the gradual decline of FIT subsidies, the price difference has widened, and overseas rooftop PV users have turned to configure energy storage to achieve a higher proportion of spontaneous self-use. Peak-valley arbitrage: California, Australia, major European countries, China, etc., have time-of-use tariff mechanisms, under which the energy storage system charges energy storage through the low period of the grid at night, and discharges during the peak of electricity consumption during the day, and saves electricity costs by using the peak-valley price difference. Virtual power plant: Based on the energy software management platform, the distributed energy storage system integrator integrates the distributed energy storage system scattered on the user side, analyzes, controls, and optimizes the operation of the energy storage system, and participates in power grid services to obtain application benefits. The optical storage integrated machine adopts DC coupling, which has higher comprehensive efficiency. At present, for different household needs in the market, according to the different degrees of integration, household energy storage systems can be mainly divided into optical storage units and energy storage units. Light storage machine, as the name thinks, by integrating the photovoltaic inverter and two-way converter, placed inside to form an integrated system. The integrated mode mainly adopts the DC coupling mode, which is ready to use, and realizes the integrated solution of "light + energy storage", which is suitable for the incremental market of synchronous installation of household photovoltaic and energy storage systems. The energy storage split machine is suitable for the installed household photovoltaic stock market, and the internal AC coupling mode is usually used to facilitate the connection with the photovoltaic inverter of the original photovoltaic system. The efficiency of the DC coupling mode is significantly higher than that of the AC coupling mode in the mode of power generation during the day and power consumption at night, and the mode accords with the power consumption habits of most contemporary families, and the efficiency of the two is about 95% and 90% respectively. The optical storage machine is highly integrated and effectively reduces the soft cost. NREL data show that the hardware cost only accounts for less than 50% of the total cost of household energy storage system, and the optical storage machine due to its highly integrated characteristics, no additional installation of photovoltaic inverters, on the one hand, reduce the hardware cost, on the other hand, can save one-time equipment investment, simplify installation, save installation costs, and facilitate after-sales maintenance. Effectively reduce subsequent soft costs. BNEF predicts that the future cost reduction of soft costs will be much lower than lithium batteries and inverters, and in the case of similar hardware equipment costs with split machines, the soft cost advantage of integrated machines will be further highlighted in the future.

1.3 Power supply reliability promotes further development of household storage

Frequent accidents, energy storage maintenance power supply stability. Sudden power outages, affect more than 100,000 people and have an outage duration of> 1 hour frequently occurring worldwide. The United States, Canada, Australia, Brazil, India, and other countries have the largest number of power outages, which are generally characterized by vast land areas, large power supply spans, and complex power operation conditions. North American power grid system facilities are old, and Asia, Africa, and Latin America lack strong power infrastructure construction investment, resulting in frequent power outages, power shortages, superimposed climate warming, cold waves, tornadoes, high-temperature drought, and other extreme climate, residents need emergency power supply is just a need. Household storage provides emergency power in power plant accidents or extreme natural disaster events to improve power stability. Globally distributed photovoltaics and household storage are still at a low level in the initial stage, the light storage penetration rate in most areas is below 10%, and the development space is large.