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How To Choose Energy Storage Batteries?
- Jul 23, 2018 -

One: The status of battery energy storage


From the external point of view, China is an energy importing country, 60% of its energy depends on imports, which brings great risks to the energy security strategy. From the internal point of view, coal and electricity consumption accounts for more than 60% (before 2016), improving energy structure, developing new energy and clean green energy. Urgent affairs.


Wind energy and solar energy are the absolute main force of new energy generation, but all have the characteristics of large fluctuation and difficult to predict. The battery energy storage has the characteristics of quick dispatch response, flexible configuration, precise control and friendly environment. It has become the best partner of new energy generation, which has been recognized by the industry and has been recognized by the relevant departments of the state.


Although gas power generation and pumped storage power stations can also complete some new energy peak shaving work, the smooth output and frequency modulation effect is far less than that of battery energy storage. The wind power and photovoltaic power generation in the same place can naturally balance part of the output fluctuation (such as the wind and wind complementation effect), but the time of neither wind nor light will occur, so a certain scale of battery energy storage power station is the ultimate choice for the new energy power station to realize the tracking plan.


According to the authoritative department of the state, by 2030, the installed capacity of wind and solar power will reach 833 million kilowatts in China. Assuming that 2% of the proportion of energy storage, new energy generation supporting energy storage installed capacity will reach at least 16 million kilowatts.


There are various forms of energy storage power station supporting new energy generation, such as light storage, wind storage, scenery and so on. From the use effect, utilization efficiency, dispatch convenience and business model, the author thinks that the independent energy storage power station of 100 megawatts will occupy the main position.


Two, the value of battery energy storage


Battery energy storage has both economic value and social value (all kinds of value other than economic value). From some point of view, its social value is far more than its economic value, such as its military value, the value of electricity security, the value of energy strategy and so on. Only from economic value, it mainly depends on its size and use, such as rechargeable treasure can only solve the problem of mobile use of one or two mobile phone users for one day; family energy storage or emergency storage power supply can only solve the problem of partial household electricity or temporary power outage; user side storage can only consider the use of peak valley electricity price difference. Problems such as peak valley and demand side response.


The economic return period of several energy storage applications listed above is long or not, and there is even a certain risk of investment (for example, the user side storage can have the potential to extend the estimated return period due to the smaller peak valley price difference).

In contrast, large-scale energy storage (above 100MWh) has a huge social value, such as fast response speed, precise control and two-way regulation, such as the power grid dispatching in the field of power grid security strategy such as FM peak regulation and so on. At the same time, the return is also rich (mainly FM service fee, capacity service fee, etc.), but the premise is to have The open electricity market (including power assisted services market).


Three, the main battlefield of battery energy storage in the future


Although the new energy micro grid, distributed photovoltaic power generation and the user side peak peak filling (peak cutting) will use energy storage technology, I think the field of large scale application of battery energy storage will be the side transmission and distribution of power grid. The battery energy storage power station, which is more than 100 megawatts, independent and directly dispatching by the power grid, can not only guarantee the power supply safety of the power grid, but also improve the power quality of the local area. The battery energy storage will even subvert the traditional design concept and design rules of the power grid, improve the utilization rate, reduce the waste of resources and delay the waste of resources. Increase the construction cycle.


With the gradual liberalization of the electricity market in the future, the spot market and auxiliary services market will generate a large number of energy storage power plants.


Four. Selection of energy storage battery


As a photovoltaic power generation, the energy storage power station is a very important part of the energy storage power station. The energy storage battery is a very important part, which must meet the following requirements.


It is easy to achieve multi mode combination to meet higher working voltage and higher working current; the capacity and performance of the battery can be detected and diagnosable, so that the control system can control the load of the power station under the condition of the capacity and performance of the battery; high safety and reliability: under normal use, the battery normally uses life. Life is not less than 1--5 years; in the extreme case, even if a fault occurs in a controlled range, explosion, combustion and other failures that endanger the safe operation of the power station should not occur; with good rapid response and large rate charge discharge capacity, 5-10 times the charge discharge capacity, high charge discharge conversion efficiency, easy installation and maintenance; It has better environmental adaptability and wider working temperature range.


From the initial investment cost, lithium ion battery has strong competitiveness, sodium sulfur battery and all vanadium redox flow battery have not formed industrialization, supply channels are limited and more expensive. In terms of operating and maintenance costs, sodium and sulphur needs continuous heating, and all vanadium redox cells require a pump to control the fluid, increasing the operating cost, and the lithium battery almost does not need to be maintained. According to the application status and battery characteristics of energy storage power station at home and abroad, it is suggested that the battery selection of energy storage power station is mainly lithium iron phosphate battery. The reason for not recommending the use of lead-acid batteries is battery life. Large brand lead-acid batteries have a life span of about 2.5-3 years in the case of frequent charge and discharge, and the life of lithium batteries will be much longer.


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