Victron Energy ESS Energy Storage System

Solar power plant energy storage.

Starting in 2022, new unfavorable regulations for the purchase of electricity will come into force for all new prosumers, i.e., owners of photovoltaic power plants. Until now, it could be balanced, i.e., stored in a power plant, in a ratio of 1 to 0.8 or 0.7, depending on the size of the solar installation. It was a perfect solution because you didn't have to invest in your own electricity storage. Unfortunately, beginning in 2022, this good period will end, and power plants will buy electricity from prosumers at an average price, which means selling it for about PLN 0.25 per 1 kWh. This is completely unprofitable and in such a situation it is much better to invest in your own electricity storage to become as independent as possible from the energy company.

Unfortunately, the average cost of purchasing 1 kWh electricity is about PLN 0.7. This means that we have to produce as much as 2.8 kWh from our own installation in order to be able to buy 1 kWh from the power plant. In such a situation, it is definitely better to use your own energy storage and save as much as PLN 1.96 per 1 kWh.

The operating principle of energy storage

Independent energy storage operation is not complicated. The central management unit, e.g., the MultiPlus-II GX, manages the entire process automatically according to the programmed scheme. Equipped with its own kWh meter, it can assess the power currently produced by your solar power plant and transmit this information to the battery inverter. If the power is too low and the amount of energy in the batteries is sufficient, the system automatically switches to battery power.

However, if your power plant produces enough energy, instead of sending it to the public power plant for pennies, the system stores it by charging the batteries. In this way, the stored electricity can be used at night or on cloudy days when production is insufficient. In a situation where the batteries are discharged and the solar power plant does not produce enough energy, it is taken directly from the energy company. The system, on the other hand, does not use public grid energy to charge the batteries, as such an operation would not make economic sense.

Is energy storage profitable?

If we take into account that our overproduction requires sending energy to the public plant with a value of PLN 1.96 or 2.8kWh, then the stored energy, e.g., 1 MWh (i.e., 1000 kWh), means savings of PLN 1960. 1 MWh is produced annually from an average of 4 solar panels, i.e., a relatively small amount. If your power plant creates an average overproduction of about 5 MWh, savings may reach PLN 9,800 each year. As you can see, unfavorable regulations significantly increase the profitability of energy storage.

Energy storage and uninterrupted power supply.

In addition to the economic aspects, each energy storage unit offers us energy independence. Thanks to the configuration, we can easily allocate a small part, e.g., 15% of the batteries to emergency power supply. In such a situation, even after the power supply from the energy company is completely turned off, we will have a reserve to run the refrigerator, the lighting, or the TV. If we exclude electronic devices that consume large amounts of energy, the backup time may even last several days. Also, a well-balanced and configured energy storage system can make the amount of energy used from the network negligible and we will only pay for the subscription and maintenance of the connection.

Which energy storage batteries should be used?

Energy storage batteries are used often and are deeply discharged each time. In such a situation, the LiFePO4 Lithium Gel Phosphate battery will be the best choice. These types of batteries are characterized by very high endurance and durability. When fully loaded, they can last for 7 or more years. However, if the system is not extremely loaded, it can last up to 20 years. The key issue here is the choice of batteries. 

Unfortunately, as with everything, there is an abundance of cheap LiFePO4 batteries produced in China at the lowest cost. These are cheaper but also very unstable and, after 2-3 years of intensive work, they will possibly need to be replaced at a high cost.

Replacing batteries not only involves the cost of purchasing new batteries, but also the additional expenses of disposing of hazardous old batteries. Also, the fee for installation services, if we do not want to undertake the replacement ourselves, may turn out to be an additional unforeseen and unplanned cost.

Another aspect is safety. Often the size of the battery bank is 400 or even 1000Ah. This means a very large amount of lithium. If low-quality batteries do not maintain stable conditions (e.g., by permitting temperature changes, allowing too-rapid charging, or permitting too much voltage discrepancy between cells), the battery bank may catch fire, which could lead to a fire in an apartment or house.

Victron Energy energy storage

Our company offers comprehensive energy storage solutions based on the products from the Dutch manufacturer Victron Energy. The company is recognized world-wide as a pioneer of photovoltaic solutions and at the same time is known for the high reliability and efficiency of its devices (as evidenced by a 5-year warranty on products, as well as by a large community around the world that has been using the company's products successfully for many years).

Also, the possibility of full customization, according to the customer's preferences, is an advantage that other companies do not offer. This can be done easily using a computer on the local network or via the Internet. It is also possible to observe the operation of the system over time using the VRM portal from Victron Energy.

By choosing products from the Victron Energy brand, you get a guarantee that not only the devices, but also the LiFeP04 batteries, will operate stably for years. Most importantly, because their production quality is the highest in the world, you can be sure that the batteries are safe because the risks of destabilization and fire have been completely eliminated.