with the advent of the grid parity era, both distributed energy in microgrid and centralized new energy power plants will usher in scale-up development. however, the status and responsibility of new energy in the power system are not equal, and the key solution to turning new energy from grid parity to equality is energy storage. however, the energy storage for new energy is always a "sugar-coated burden". tbea sunoasis is trying to break the deadlock by the new-generation energy storage product and solution.
at the snec expo 2020, dr. huang lang, general manager of microgrid product line of tbea xi'an electric technology co., ltd., a subsidiary wholly owned by tbea sunoasis co., ltd. commented on the development of microgrid and energy storage: driven by the quick decline of energy storage cost, the market-oriented operation of microgrid can be soon realized; with the issuance of relevant policies, we may see the explosive growth of energy storage market at the source side by the end of next year.
huge demand for grid-connected microgrid in domestic market
on jul. 21, 2020, six ministries and commissions including the ministry of industry and information technology (miit) jointly released the catalog of smart pv pilot demonstrative projects that included the demonstrative project of source-grid-load-storage coordinated microgrid of tbea xi'an industrial park. the new catalog puts microgrid once again in the spotlight.
since the national energy administration (nea) published the first batch of microgrid demonstrative projects in 2017, the power industry has been holding high expectation on microgrid. in 2018, jiangsu provincial development and reform commission issued the guiding opinions on promoting the development of distributed energy and microgrid that planned to build up 20 microgrid demonstrative projects by 2020. the nea also issued a file to clearly require that the power supply enterprises should not reject or postpone the connection to microgrid and distributed energy projects to facilitate the growth of microgrid projects. however, different from the prosperity in foreign countries, the domestic microgrid development tumbles in a dilemma of "much cry and little wool".
according to dr. huang lang of tbea sunoasis, differences in microgrid development at home and abroad attribute to reliable and resilient power grid in china. although china has a vast territory, the coverage of power grid has reached 99%, and only a few military bases and remote islands have the demand for off-grid microgrid. but in some other countries such as the african countries with no grid coverage, the local demand for microgrid is much larger.
however, due to the mammoth capacity of distributed energy market in china, the grid connection of a huge number of distributed power plants brings some difficulties that can be solved by grid-connected microgrid through the source-grid-load-storage coordination. dr. huang said, "the domestic market of grid-connected microgrid is extremely large but so far its commercialization has not been well proven, and thus its real scale-up and market-oriented development needs to take some time."
microgrid energy storage is the pertinent solution
energy storage may be the main obstacle that hampers the commercialization process of microgrid.
with respect to the market value, microgrid can serve as an auxiliary power service to respond at the demand side and help adjust the stability of power grid. however given the imperfect power market and immature pricing mechanism in china, the tariff cannot reflect the accurate supply and demand relation, and thus the value of microgrid is not fully demonstrated. in terms of cost composition, the cost of microgrid mainly consists of distributed power generation and energy storage. so far the distributed power generation is close to grid parity so the cost of microgrid turns out to be the most critical factor of the cost of microgrid project. "fortunately the cost of energy storage has a sharp decline in 2020 and the market-oriented operation of microgrid is just around the corner", dr. huang is confident in the future of microgrid.
energy storage is always deemed as a highly potential power technology. the energy storage of microgrid can store the excessive solar power for higher rate of self-consumed new energy, reduce the capacity of power distribution, utilize tariff variance to cut power consumption cost, and more importantly suppress the output volatility of distributed power generation for better quality of power supply. additionally in case of grid blackout, the energy storage may serve as the standby emergency power to sustain the voltage and frequency of microgrid. dr. huang said, "the microgrid and energy storage are a complex of multiple value and we must give full play to its multiple functions."
despite of the immature upstream and downstream of the microgrid industry, considering the demand of market and clients, tbea sunoasis adopts a relatively open business model: on one hand the company provides services such as project development, investment and financing, epc/boo/bot, etc. to meet clients' demand, and on the other hand the subsidiary tbea xi'an electric technology endeavors to take up technical challenges and provide more cost-efficient core equipment and solutions that yield satisfactory earnings to both clients and itself.
the data center, also nicknamed as a "power tiger", is one of the important application scenarios of microgrid. the ac/dc microgrid project of the district-level data center in dongguan southern power grid industry zone uses the four-port ac/dc electric energy router developed by tbea sunoasis, which solves the problem of power distribution efficiency and capacity of data center, and has a prominent cost-saving effect.
the solar energy storage and charging microgrid project tbea xi'an industrial recently listed in the miit's demonstrative project catalog is a typical case of microgrid commercialization. it is provided with 2mwp pv and 1mw/1mwh lithium battery storage system as well as 960kw charging points. according to dr. huang, the project is highlighted by the application of intelligent energy management system for optimization and coordination, which improves the self-consumed rate of solar power and utilizes the energy storage system for arbitrage of peak-valley price difference to cut down both the tariff of basic capacity and the tariff of electric output. moreover, the load side including air conditioners and electric vehicles is involved in the response of power demand within the microgrid that brings considerable overall economic benefits. compared with the original power distribution system, the new one saves about 1.723gwh of power consumption each year and reduces the general cost of power consumption by over 60%. in comparison with the conventional solution of pv solar storage system only, the new system reduces the tariff by 10.5% but uplifts the project investment return rate by 11.7%.
pertinent to the problems incurred in microgrid development, tbea sunoasis recently proposed an intelligent solution of "one core, two drives and x scenarios" that organically combines its advantageous products like electric energy router, energy management system, energy storage system, etc. and can be applied to a variety of scenarios including industrial and commercial parks, data centers, islands and the areas without power access.
priority on the cost of energy storage for developing new energy
apart from distributed power generation, the demand of energy storage for the centralized new energy power plants is also increasing. since xinjiang autonomous region took a lead in the demonstrative project of pv/energy storage combined operation, in 2020 a dozen of provinces encourage or require the provision of energy storage facility to the newly built pv and wind power projects. the domestic power giants such as state grid, spic, huaneng and huadian all started bid tendering for the energy storage projects for pv power plants.
dr. huang gave an affirmative comment, "the trend of new energy project equipped with energy storage facility is inevitable." with the expanding proportion of power generated by new energy facilities and the increasing number of grid-connected distributed power units, the volatility, intermittence and randomness of new energy bring heavier pressure on the grid stability, and randomness at consumption side such as charging of electric vehicles makes the grid control and regulation even more challenging. energy storage is able to balance the power system in different time scales.
"at the generation side of new energy, energy storage has diversified functions like peak shaving, frequency regulation, voltage regulation, suppression of frequency fluctuation, improvement of prediction accuracy, etc. such strength happens to make up for the latent weakness of new energy", dr. huang believes that driven by various policies of local governments, the explosive growth of energy storage market at the source side will probably appear before the end of next year.
however, the new energy power generation enterprises that just realize grid parity cannot afford the costly energy storage. without supportive policy, quite a few functions of energy storage cannot be realized and the project costs not be effectively recovered. "energy storage" might become the extra burden of these power generation enterprises. in view of this issue, tbea sunoasis takes higher voltage level and bigger system capacity as a feasible solution to reduce cost.
at the snec expo 2020, tbea sunoasis solemnly launched the energy storage converter with 1500v dc voltage and the largest single unit capacity of 1500kw. boasting many advantages of lower cost, higher efficiency, friendliness and multi purposes, it can be applied as the energy storage system at the generation and grid sides, which will be a new impetus of commercialization of energy storage.
most of domestic energy storage systems have a dc voltage below 1000v. tbea sunoasis' 1500v energy storage converter has a maximum conversion rate of 99%, and the cost per watt is 10% lower than that of 1000v converter. at the same time, the company launched a 3mw large-capacity integrated energy storage unit equipped with this energy storage converter that has multiple functions by virtual synchronous machine technology such as inertia response, primary and secondary frequency and voltage regulation, peak regulation, fluctuation suppression. it gives full play to the multiple values of energy storage and reduces the lcoe of energy storage system by 3.2%.
tbea sunoasis believes that new energy must shift from grid parity to the dual focus on both parity and equality so as to usher in scale-up development. the new energy power plant equipped with energy storage facility can be more friendly and supportive to the power grid. the target of parity and equality can be finally realized by declining lcoe of energy storage and maturing power market in china. in the future, tbea sunoasis will also concentrate on providing all-round solutions, target at low cost, high efficiency and reliability, speed up the energy storage layout at grid side and source side, and further transform the patterns of energy production and consumption.