The popularity of solar panel systems is continuously growing in Hungary, as they enable the production of clean and inexpensive energy. However, the question arises: when is it worthwhile to install a battery energy storage system alongside a solar panel system? A battery allows for storing surplus energy generated during the day and using it later, thereby increasing energy independence and reducing electricity bills. At the same time, it is a significant investment, so it is important to understand its advantages, operation, regulatory environment, and expected return on investment. Below, we will review these aspects in detail, yet accessibly.
How does a battery-powered solar system work?
The essence of the system is to allow the energy generated by solar panels to be used not only immediately but also later. Its operating principle in brief: while the sun is shining, the solar panel system supplies energy for the property's current consumption, and stores the surplus in a battery. During the day, if the battery is full, any further surplus generation is fed back into the electrical grid (if permitted). After sunset or in cloudy weather, the energy stored in the battery covers the house's consumption, and only if this is depleted do we draw electricity from the grid. With this solution, you can utilize excess energy generated during the day in the evening or at night, reducing the amount of electricity purchased from the grid.
Operating modes and functions: Modern battery inverters can operate in several modes depending on the needs:
- Maximizing self-consumption: In this mode, the primary goal of the system is to fully use the energy you generate within the house, minimizing feedback to the grid. The solar panels first supply the immediate consumption, then charge the surplus into the battery. When the solar panels do not generate enough (e.g., at night), the battery provides power, and only after it is depleted do we connect to the grid.
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Emergency (backup) mode: In this mode, the battery serves as a backup power source in case of a power outage. The system continuously keeps a certain battery capacity charged so that if the power supply fails, there is still energy for essential consumers (e.g., refrigerator, heating control, lighting). This essentially functions as an uninterruptible power supply (UPS).
- Timed charge/discharge mode: If you have a two-zone (night/day) electricity tariff, the system can be set to charge the battery with cheaper night-time electricity, then cover consumption from it during expensive daytime peak hours. This way, the energy storage can save you money on your electricity bill, even if solar panel production is not sufficient. (Note: for average household consumers, the discounted night-time "B" tariff is typically only available for certain appliances - e.g., boilers - but in special cases, it can also be used for charging the battery.)
- Off-grid mode: In this case, the household can operate completely independently of the grid. The combination of solar panels and the battery forms an autonomous energy supply system. All generated energy is stored in the batteries, and all consumption is served by them. This mode is used in locations without grid connection, or where complete energy independence is specifically desired. It is important to note that off-grid systems typically require larger and more expensive battery capacities to ensure continuous supply, especially during winter, less sunny periods.
The brain of the battery system is the hybrid inverter, which coordinates the operation of the solar panels, the battery, and the grid. In addition, many hybrid inverters also feature smart energy management (e.g., mobile app tracking of production, consumption, charge level), allowing you to easily monitor your home's energy flows.
Usage possibilities
The benefits of energy storage depend on when and how you use electricity. Some typical usage examples:
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In family homes, daytime production is often a surplus that would need to be bought back in the evening. The battery stores this energy, so you can "reserve" it for yourself. Important appliances can also remain operational during power outages.
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For small businesses, energy storage helps balance peak loads, thereby reducing demand charges and ensuring uninterrupted operation (e.g., computers, lighting).
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In remote properties, such as farms or holiday homes where grid connection is difficult, a battery is almost essential for off-grid operation.
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For conscious users, a battery is not just a financial but also a strategic decision: it promotes energy independence, reduces the ecological footprint, and provides protection against electricity price increases.
So, a battery truly pays off when it aligns well with your energy consumption habits. To ensure proper sizing and system setup, it is always advisable to seek expert assistance.
Hungarian regulatory framework and authorization
The installation of battery-powered solar systems is significantly influenced by the domestic regulatory environment. In recent years, several important changes have occurred, determining when and how it is worthwhile to install energy storage alongside solar panels. Below, we summarize the most important information:
Restriction on grid feed-in: After October 31, 2022 – temporarily and indefinitely – new household-sized solar panel systems with grid feed-in could not be authorized in Hungary. The government justified this step by the overload of the electrical grid. In practice, this meant that anyone installing solar panels after this date could not feed the surplus into the grid unless a relaxation occurred later. As a result, interest in batteries surged, as anyone considering a new system could only utilize the generated energy with their own energy storage. In the second half of 2023, the restriction began to be gradually lifted: according to the government decree, the grid's capacity was reviewed by region in September 2023, and where possible, feed-in is again allowed.
Net metering vs. gross settlement: Traditionally, household solar panel systems were connected to the grid with annual net metering, which meant that the generated and consumed energy was simply balanced on an annual basis. Until December 31, 2023, this remained in effect for previously authorized systems. However, from January 1, 2024, due to a legal change, new entrants must apply gross settlement. The essence of gross settlement is that the service provider values the energy fed into the grid and the energy drawn from it separately. The price you receive for the electricity you feed in is lower, as network usage fees are deducted from it, while the electricity you draw is billed at a higher (normal) price. In other words: the electricity fed back is "worth less" than the electricity drawn - so to achieve a net-zero annual balance, you would have to generate and feed in much more electricity than you consume. This system encourages maximizing self-consumption, as you are financially better off if you use your own production yourself rather than selling it to the grid. Here again, the battery can provide a solution: without storage, due to gross settlement, you only receive a reduced fee for daytime surplus, while with a battery, you store and use that same energy later, avoiding expensive drawing from the grid.
Authorization and notification: Good news for residential and small business installers is that no building permit is required for the installation of roof-mounted solar panel systems under 50 kW. In practice, this means that the installation of a solar and battery system for a family house or a smaller business is not subject to a building authority permit, so there are no administrative obstacles. It is important, however, that the installation must always be notified to the electricity provider (distribution license holder). The parameters of the system must be agreed upon with the service provider, and if it is connected to the grid (even if the grid is present only in an off-grid configuration), a suitable bidirectional meter must be installed, and it must be ensured that no unauthorized feed-in can occur. A separate official permit is generally not required for battery installation if the system is optimized for in-house self-consumption. However, for grid feed-in mode - due to the aforementioned restriction - a special permit is required from 2024. In all cases, it is advisable to involve a qualified designer who is familiar with the current regulations (e.g., standard connection conditions, VDE-AR-N 4105 requirements, etc.) and ensures that your system complies with legal and safety regulations.
Hungarian regulation has therefore moved in the direction of encouraging new solar system owners towards energy storage and self-consumption. If you are still under the old net metering system, installing a battery might be more a matter of convenience and security, while for new installations (under gross settlement, or in case of feed-in prohibition), the battery can play an important role in financial returns.
When does a battery system pay off financially?
Installing battery systems is a significant investment, so it is understandable that many are interested in when it pays off financially. The return on investment depends on many factors: the price of the battery and the system, your energy consumption profile, electricity tariffs, subsidies or financing costs, and the system's lifespan all influence it.
Investment cost and lifespan: Currently, the price of a lithium-ion battery for residential use, integrated (with the inverter or installation), is roughly around 200-250 thousand HUF/kWh capacity. For example, a 5 kWh capacity battery pack installed costs approximately 1 million HUF. These modern batteries are expected to operate for 10-15 years (manufacturers typically provide ~6000 cycles / 10 years warranty), with proper use, a lifespan of up to 15-20 years can be achieved. The investment pays off if, during this time, the battery saves enough on electricity bills, or provides other value (e.g., security, power outage protection) that collectively exceeds its price.
Electricity bill savings: In Hungary, the price of household electricity is tiered: up to average consumption (~2523 kWh/year) ~36 HUF/kWh, above this approx. 70 HUF/kWh (based on 2023 values). With a battery system, it is mainly worth targeting the replacement of energy in the more expensive, over-consumption band. If your consumption exceeds the average limit, every kilowatt-hour covered by the battery means a saving of approximately 70 HUF. A fully charged 5 kWh battery can ideally return 5 kWh per day. Let's assume that this capacity can be fully utilized for half of the year (approx. 180 days) - thus replacing ~900 kWh annually from the high tariff. 900 kWh * 70 HUF = 63,000 HUF annual saving. These are very approximate numbers, but it can be seen that the system could pay off in approximately 10-15 years in this scenario. If you only replaced the cheaper (basic) tariff, you could count on approximately half of this, which would double the payback period (up to 20+ years), so in this case, it is not really worth it purely on a financial basis.
Impact of net metering vs. gross settlement: If you are still under the old net metering system, the grid acts as a "virtual battery": summer surplus can be returned in winter, balanced annually, sometimes down to the last penny. In such a situation, the battery does not bring direct financial benefit; moreover, there are losses during multiple charge-discharge cycles. In this case, battery installation may be motivated more by the need for a backup in case of a power outage, or because after the 10-year net metering period expires, a switch to gross settlement will be necessary. However, with gross settlement or a feed-in ban, the battery is almost indispensable for good utilization. Since the service provider settles production and consumption separately immediately (or monthly), summer sunshine "goes as a gift" to them at a low price if you do not use it locally. With a battery, this surplus is not wasted but stored for your own use. Simulations show that up to 50-60% of the production of a gross-settlement system without a battery can go into the grid as surplus, while with a battery, the proportion of self-consumption can be increased to 80-90%. This has a significant impact on the electricity bill, especially in replacing high-tariff consumption.
Different consumption profiles: The payback is very sensitive to when you consume electricity. Let's take two households: A) "Work-from-home" household, with continuous consumption during the day (e.g., air conditioning, computers, cooking, etc.), B) "Evening consumer" household, with little consumption during the day but intense consumption in the evening (cooking, washing, entertainment). In case (A), even without a battery, the solar panel's production is utilized quite well locally, with less feed-in - here the battery adds less (it can only provide for late evening hours). In case (B), however, without a battery, a large part of the daytime production is lost (fed back), and in the evening, the house buys from the grid. Here, a sufficiently large battery can drastically (by 50-70%) reduce the energy drawn from the grid because it shifts the daytime surplus to the evening. Thus, the battery pays off much better for a user with profile (B) than for (A). In families, a mixed profile is common (at home on weekends, not during weekdays), which also needs to be taken into account in the calculation.
Corporate and individual return on investment: For businesses, the situation can be different. Small and medium-sized enterprises typically buy electricity at market prices (there is no regulated utility price reduction). Thus, a battery for them, by replacing high peak-time energy costs, could pay for itself well within 10 years. According to Energoptimo's calculations, a corporate energy storage connected to a larger solar panel system could even recoup its cost in 5-6 years due to significant consumption. Additionally, the cost of downtime due to a power outage can also be high for a company - which can be avoided with a battery backup solution, so it also has business continuity benefits, not just energy savings.
In summary, from a financial perspective, we can say that a battery system pays off within an acceptable time if the following conditions are met:
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A significant portion of your energy consumption falls into high-tariff periods or bands, or a large portion of the energy produced by your solar panels would otherwise be unsold surplus.
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There is no possibility of net metering or normal feed-in, so the battery actually replaces the "storage" role of the grid.
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The price of the battery has been reduced by some subsidy or discount, or rising electricity prices accelerate the growth of savings.
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You value uninterrupted security or independence - this is difficult to quantify financially, but it is an important consideration for many. As one expert put it: "Acquiring a battery is definitely worth it, as it provides our own peace of mind and independence" - so this should also be considered alongside financial calculations.
Finally, keep in mind that batteries are continuously evolving and becoming cheaper. Based on technological trends, prices are expected to decrease and capacity/lifespan to improve in the future, which will further enhance profitability. It is conceivable that within a few years, an energy storage unit will be a basic accessory for residential solar panels.
Popular brands
Deye
Deye is an emerging Chinese manufacturer known for its hybrid solar inverters and energy storage solutions. Its products include hybrid inverters of various capacities, capable of simultaneously managing solar production, battery charging/discharging, and grid connection. The advantage of Deye inverters is their broad compatibility with different battery types (both lithium-ion and lead-acid batteries), allowing flexible integration with various energy storage systems. They also feature advanced functions (e.g., remote monitoring platform, smart setting options). Overall, Deye solutions offer good value for money, especially in systems where open compatibility and customizability are important.
SolaX
SolaX Power is also a Chinese manufacturer specializing in residential and small business energy storage solutions. SolaX hybrid inverters (X1 and X3 series) are widely used, and their designed Triple Power batteries are modularly expandable, allowing them to be configured for both smaller and larger needs. One of the advantages of SolaX systems is that they provide a comprehensive, integrated solution - the inverter and battery are 100% synchronized, installation is relatively simple, and the manufacturer's software optimizes operation. It should be noted that SolaX inverters are typically compatible with their own batteries; they do not, or only partially, support third-party (foreign manufacturer) batteries. In return, the SolaX brand is a well-proven and reliable choice for households seeking an easy-to-operate, complete energy storage system.
SOFAR
Sofar (SofarSolar) is a dynamically developing Chinese company that offers both solar inverters and energy storage solutions. Sofar hybrid inverters and their compatible BTS series battery modules are well-known in the market. The Sofar BTS 5K is a 5 kWh lithium iron phosphate (LiFePO4) battery module, representing a long-lasting and safe technology. The advantage of these modules is their modular expandability: 1 to 4 units of 5 kWh modules can be connected in series in a single system, thus achieving capacities of 5, 10, 15, or 20 kWh in a single Sofar energy storage system. Sofar batteries have a robust design and are specifically optimized for home solar systems. Sofar hybrid inverters are also available in three-phase versions, making them suitable for apartment buildings or smaller industrial facilities. The brand's recognition is also growing in Hungary, as it provides reliable operation at competitive prices. In summary, Sofar is a brand where flexibility and scalability are major advantages – the system can grow with your needs.
Huawei
Huawei is a giant in the global technology sector, having introduced innovative solutions not only in telecommunications but also in energy. Huawei solar inverters are renowned for their outstanding efficiency (98-99% max. efficiency) and smart features. Huawei's smart energy management system (FusionSolar) allows for precise monitoring of production, consumption, and battery charge levels with 15-minute updates, and newer models even feature AI-based fault detection (AFCI). In terms of energy storage, Huawei offers a complete system with its proprietary LUNA2000 lithium-ion battery. The LUNA2000 has a modular design, consisting of 5 kWh units, and typically 5-30 kWh capacity can be configured as needed. It's important to know that Huawei inverters are only compatible with Huawei's own LUNA battery (they do not support third-party batteries). This intentionally results in a closed, optimized system, in return for which the components work together perfectly, and Huawei provides a full system warranty and service. In terms of price, Huawei falls into the premium category, but the quality and features offered can be convincing for many. If you want an energy storage system that represents cutting-edge technology and is reliable in the long term, Huawei is an excellent choice.
BYD
BYD (Build Your Dreams) is one of the world's leading battery manufacturers, a Chinese company that, despite its name, has grown into a global brand. BYD has a broad portfolio, ranging from electric vehicles (buses, cars, trucks) to household energy storage systems. In energy storage, BYD is a pioneer in lithium iron phosphate (LiFePO4) technology, which means safer cells (cobalt- and nickel-free, not prone to overheating) and longer lifespan. BYD's most famous product is the Battery-Box Premium series (HVS/HVM), which can be built as a modular battery tower. For example, the HVS tower stacks 2-5 modules, with scalable capacities between 5.1-12.8 kWh, while the HVM ranges from 3-8 modules, from 8.3-22.1 kWh. The modular design is a proprietary patent – an internal cabling-free "stacking" system – which allows for easy installation and flexible expandability. One of the biggest advantages of BYD batteries is their wide inverter compatibility: the most renowned international inverter manufacturers (e.g., Fronius, SolarEdge, GoodWe, etc.) all officially support connecting the BYD Battery-Box. So, if you choose a BYD battery for your system, it's highly likely to integrate well with your existing inverter. BYD products are also available in Hungary, primarily popular in premium category systems or among demanding users who invest in uncompromising quality for the long term when choosing a battery.
Leapton
Leapton Energy is a company with Japanese roots, known for its solar panels, but recently entered the energy storage market. Leapton promises Japanese precision and quality, combined with the efficiency of Asian manufacturing – its solar modules are Tier-1 rated, with manufacturing plants in both Japan and China. Its battery product line, the Leapton EH-A05, is a lithium iron phosphate (LFP) technology energy storage system. Its specialty is modular expandability: starting from a base 5.12 kWh module, the capacity can be expanded to 10.24 / 15.36 / 20.48 kWh as desired, simply by stacking modules. Smart monitoring was a key focus in the design of Leapton batteries: their built-in battery management system (BMS) continuously monitors charging-discharging parameters and provides 24/7 monitoring to the user via a smartphone application. The system is also flexible in terms of compatibility, working with several well-known inverter brands (according to the manufacturer, it can be integrated with ~15 different inverter types). In summary, Leapton is a new player in energy storage, drawing attention with its reputation for Japanese quality and the safe LiFePO4 technology. It may be worth considering, especially if you are looking for a complete solution where both the solar panel and the battery come from the same brand family (Leapton solar panels + battery combination).
Final thoughts
Battery energy storage adds a new dimension to solar panel systems: it allows you to maximize the use of the solar energy you generate yourself and become less dependent on the electricity provider. However, for this to be worthwhile, it is important to consider individual circumstances.
Our goal is for your solar investment to serve you as best as possible in the long term, both financially and in terms of convenience. And battery energy storage - with good timing and careful planning - can be the key to this. Thank you for your attention, and we wish you much success on your green energy journey!