Battery hybrid systems are more complex than on-grid systems and require professional installation and adjustments. They are not recommended for outdoor installation, and installation inside a house requires very serious fire protection measures, claim the representatives of the Association of Prosumers and Energy Communities (APCE), which yesterday launched a new Information Guide for future prosumers who will also use storage systems.
“Our predictions are that in a maximum period of 5 years from now, in Romania, almost 70% of prosumers will turn to storage.
The reasons are multiple: first of all, through storage, prosumers will have great energy independence, the price of accumulators drops annually by tens of percents with short payback times and storage offers immunity to electricity price fluctuations and network overvoltages, among many other benefits”, said Dan Pîrsan, president of APCE.
The new prosumers, beneficiaries of the Casa Verde 2024 program, will not be able to modify the system once installed for a period of 6 years, except for the addition of additional storage batteries, financed from their own funds.
Those who want to maximize their system can only do so at the beginning, both in terms of the number of panels and the inverter, which will have to be able to charge the batteries until sunset, during the winter. In the future, only adding batteries will be possible.
Therefore, APCE’s recommendation is that, in the case of a more limited budget, the accumulators should remain at the moment at the minimum energy capacity of 5 kWh, allowed by the program, with subsequent additions.
Photovoltaic panels with the best efficiency and technology at the moment
The world’s best solar panels are evaluated based on several factors, such as energy conversion efficiency, durability, warranties offered, manufacturing technology and low-light performance.
“APCE recommends that you ask the installers for monocrystalline photovoltaic panels with PERC, Half-Cut or bifacial technology, with N-type and TopCon technology, which are the most advanced at the moment, offering high yield and long-term performance. Ask for a return of over 22% and a certificate of compliance in Romanian,” say the authors of the Guide.
Hybrid inverters
The best hybrid inverters on the market are rated based on efficiency, compatibility with various batteries, load management technology and advanced monitoring and control features, as well as safety and protection features.
“First of all, ask the installers to choose a hybrid inverter with short-circuit protection and which triggers the fuses in the house in the absence of the grid. There are only a few brands available in Romania with this function, and these inverters are produced by top manufacturers”.
Important differentiating factors between hybrid inverters are:
- Battery compatibility: able to work with batteries from different manufacturers, including lithium batteries.
- Back-up functions: not all hybrid inverters have back-up capability. Models that offer this feature are essential in areas with frequent power outages.
- OFF-Grid functionality: It is essential to request this option for hybrid inverters.
- Mandatory, for monitoring, ask to have a Smart Meter installed
An extremely important component is the Battery Management System (BMS)
The battery management device (BMS) is essential to manage and protect the batteries connected to an energy storage system. The BMS monitors the voltage, current, temperature and other critical parameters of the batteries to prevent overcharging, full discharge, overheating or other damage that may occur.
The BMS component must be compatible with the type of battery used and ensure optimal power management. Ask the installer to fit a quality BMS with active balancing and minimum 100A capacities.
(Balance – active balancing: ensures that all cells in the battery are charged evenly, preventing imbalances that can affect battery performance and life).
Accumulators for indoor installation
The only viable option for batteries are the LFP type (LiFePO4 – Lithium, Iron, Phosphate), which communicates directly with the inverter. Other types, such as those with lead-acid or gel, are outdated and dangerous technologies, with no return on investment in time and which should not be accepted within this budget.
“Due to the fact that the price of quality materials has decreased year by year, and the total budget is 6,600 euros, future prosumers beneficiaries of the Green House 2024 program can benefit from a hybrid system with very good quality, world-class materials, with a power of 4-5 kW.
Such a system can provide energy for an average house and can supply critical equipment during power outages or in the evening, when the panels do not produce energy,” concluded Dan Pîrsan.
