Obtaining electricity from renewable sources – especially popular photovoltaics – is not everything. To fully use the potential of renewable energy sources, this energy must be stored. In this way, we can significantly increase its self-consumption, ensure energy security in the household and support the Polish energy sector. What is worth knowing about energy storage?
Storing electricity pays off
The biggest advantage of storing electricity generated by a home PV micro-installation is increasing self-consumption. Even in the case of a small energy bank, we can increase the self-consumption rate by about 30%. Increased self-consumption translates into financial benefits. Storage allows for the effective use of a renewable energy source and reduces electricity bills.
The undoubted advantage of storing electricity for your own needs is filling the gaps in the electricity supply. By equipping your home power plant with special devices for storing electricity, you cut yourself off from power outages caused by power grid failures. In other words, you ensure continuity of energy supply. However, this is only possible in the case of a hybrid system with an emergency power supply option (but more on that later in the article).
The issue of balancing electrical loads cannot be forgotten. If the energy generated by PV modules is not stored, it must be used immediately. Otherwise, it will be sold to the grid at a price that is unfavourable to the prosumer. Storage allows it to be used when the efficiency of photovoltaics drops – e.g. in the evening or at night. This in turn relieves the power grid.
The problem with storing electricity by prosumers
Most photovoltaic installations operating in Poland are so-called on-grid systems. Such photovoltaics generate electricity from free solar energy, but there is no way to store it. Any surpluses - which are really large during peak hours, especially in summer - are transferred to the power grid. According to the new rules adopted in April 2022, prosumers settle accounts with the power plant according to the net-billing system. That is, they transfer the excess energy produced and thus top up their prosumer account. In the event of increased demand, they can buy energy from the grid - reducing the funds in their account. Additionally, they must pay a variable distribution fee.
An alternative to the on-grid system is an off-grid installation. This is nothing more than photovoltaics with a special energy storage of a certain capacity, in which the generated surplus energy is stored for later use. Off-grid photovoltaics are not connected to the grid, which means that they must fully meet the energy needs of the house. Poorly designed installations can deprive household members of access to energy. Is it possible to store electricity and at the same time cooperate with the grid and thus protect yourself against the negative effects of energy shortages? Yes! The solution is a hybrid installation that combines the functions of on-grid and off-grid systems.
Hybrid installation – a solution tailored to the needs of prosumers
A hybrid installation is a solution that, on the one hand, increases the self-consumption of energy produced by photovoltaic modules, and on the other hand can serve as a potential source of emergency power supply. The truth is, however, that not every hybrid installation has the ability to function in off-grid mode, i.e. when the power supply from the power grid is cut off. In many cases, the hybrid installation is switched off when the grid fails.
In order for a hybrid photovoltaic system to operate off-grid, an additional backup power supply system (ASS) is required. It is also often necessary to adapt the electrical installation. Thus, during a grid failure, a hybrid system with a properly configured ASS can switch to off-grid mode, providing power for a home or business.
As a result, hybrid photovoltaic systems not only provide benefits related to greater self-consumption of energy, but also potentially can become an independent source of energy in emergency situations. However, it should be remembered that the latter function is not default for all systems and often requires additional equipment (Backup Box in the case of Huawei systems) and modification of the installation.
Interestingly, despite higher initial costs, investing in a hybrid set pays off more, as we wrote here:
5 reasons to choose a hybrid photovoltaic installation
How to choose an energy storage?
We already know that energy storage is possible and, most importantly, it brings benefits. The key is to choose the right energy bank. What to pay special attention to?
The key is to choose the optimal storage capacity. A bank with too small a capacity will not work effectively with a photovoltaic installation – the energy collected will not cover the actual demand. On the other hand, buying a storage that is too large is a waste of money. According to the basic rule, the storage should have a capacity equivalent to the power of the photovoltaic installation. For example, a 5 kWp photovoltaic bank should be selected.
As a rule, if the greatest electricity consumption occurs during the hours of its lowest production (e.g. in the evening), it is worth considering buying a larger storage. Otherwise, a small storage, selected according to the above principle with a capacity equal to the installation power, will be completely sufficient.
It is worth paying attention to the technology in which the warehouse was made, safety, certificates held and compatibility with individual hybrid inverters. Miellec energy banks use the safest lithium-iron-phosphate cells (LiFePO4), low voltage and intelligent energy management systems. The warehouses comply with the EN directive required in the EU and have a safety certificate. They are compatible with popular inverters available on the market, and their energy efficiency reaches as much as 98%.
Energy storage is the future of Polish energy and the security and energy independence of individual prosumers. Choose a proven solution and enjoy excellent quality for years!
