With the 60cent/kWh feed-in tariff next year and the expiration of the "gross feed" package, Australia is about to enter the era of full "net feed". This means that if you can't "self-use", the user's on-grid tariff will be reduced to one-tenth of the previous one, 6cent/Kwh. Even though the price of the battery is still very "astounding", based on the analysis of the return on investment in many aspects when the battery has a service life of about 10 years and the first maintenance starts from about the third year, it can break even in about 7 to 8 years. During this period, users can enjoy UPS services, optimize the power factor and independently adjust the power purchase demand from the grid. This article will introduce and analyze a set of residential energy storage systems completed recently.
The user has a 4kW microinverter system. Because it is a standard household system, more than half of the solar power generation is online. Fortunately, many people in Australia leave work at 3 or 4 o'clock, and they can consume part of the afternoon's power generation.
After the battery storage is installed, because it is an AC Coupled system, solar power will give priority to meeting the needs of electrical appliances. Subsequently, the surplus electric energy will not generate electricity to the grid but will charge the battery through a two-way inverter input AC/DC conversion. If there is excessive demand for electrical appliances during the start, the battery starts to discharge to make up. If necessary, the grid will also supply power.
If the battery is fully charged during the period and there is surplus solar power, the surplus power will be generated and connected to the grid.
Since we have installed the monitoring system in advance, the operation from the energy storage system is very obvious compared to before the operation.
To sum up, it can be proved that a reasonable energy storage design and reliable products can fully realize the expected guarantee to customers.
In the design, I personally think that the key points are the selection of the two-way inverter (the SP Pro SPMC240-AU model of Selectronic is used in this design) and the design of the storage battery capacity, and the premise is a set Completed survey report on consumer electrical appliances. Thank you for the grid-connected energy storage, which greatly reduces the risk of the system and improves the compatibility of the system in all aspects. It is almost difficult to use inverters of different brands in off-grid systems (this system always uses SP Pro and APS inverter systems). For the design of the battery library, the most critical point is how to grasp the autonomy day. For a reliable urban power grid, the outage time is only a few hours, which also minimizes the difficulty of design. For this system, there is no doubt about the system design concept, but the drawback is that it relies too much on solar energy. In other words, for non-benign solar power generation areas with cloudy or rainy areas, the payback period of the system will be greatly extended. Some time ago, I heard a new saying, charging in the peak-valley price period and discharging in the peak-valence period. Regarding the current price of a set of systems and the charging and discharging efficiency of the battery, I personally feel that it is better to think about it, although it is not economical.
Regarding the current rapid development of energy storage technology, my personal view is that the innovation point of the system is still in the battery bank. Whether it is an old-brand lead-acid battery or a new-type lithium battery or a cobalt-nickel battery, there are many places to look forward to and develop.
