Energy storage facilities

We supply and install storages of both smaller capacities for companies’ own use and large commercial storages for both in-house use and for the provision of system services.

Our storage models are solutions from the biggest and best providers (LG, Sungrow, Intilion, BYD), both as off-the-shelf solutions and scaled to specific needs.

The RES Act defines an energy storage facility as a separate device or set of devices allowing energy to be stored in any form. It is important that the method of storage allows for partial energy recovery and does not cause emissions that are harmful to the environment.

Electricity can be stored in the following ways:

• direct – as electric and magnetic fields,
• indirect – in the form of kinetic, potential or chemical energy.

Storage methods are also divided into:

• mechanical – e.g. in pumped storage power stations, electrochemical – in rechargeable batteries and accumulators,
• chemical – converting energy into hydrogen or methane,
• electrical – in supercapacitors,
• thermal – heat storage.

Battery systems are most commonly used in photovoltaic installations or for own use.

Batteries can operate on-grid (connected to the power grid) and off-grid (independent of the power grid). The panels capture energy from the sun’s rays and convert it into direct current. The current generated in the cells is transferred to a hybrid inverter, which directs it to a storage facility or converts it to alternating current. This can then power all the devices on the grid connected to the photovoltaic installation.

However, the sun does not reach the earth with the same intensity all the time. For this reason, photovoltaic panels do not produce exactly the same amount of energy at all times. Their output is much higher on sunny days than on cloudy days and in summer than in winter. At night, the panels are idle. Surpluses produced during the day and not consumed by receivers can be stored in an energy storage facility for the night and in periods of lower production capacity (e.g. more cloud cover).

In an on-grid system, surplus electricity goes into storage instead of being fed into the grid. This means that the energy produced and stored can be consumed at any time.

In addition, photovoltaic batteries also allow you to store electricity drawn from the grid. You can use this solution when you have a tariff with a cheaper price at night. In winter, photovoltaic panels are less efficient, so you may run out of the electricity you produce during peak hours. In this case, you can use a supply purchased at a promotional night price. However, this solution will work especially well for companies and factories that periodically run a large number of machines (not anticipated in the power calculations that were made for the photovoltaic installation project).

Batteries in off-grid installations:

An off-grid installation is not connected to the external power grid. The lack of a physical connection means that no power can be resold from such an installation or bought back in the event of panel downtime. The photovoltaic modules are then a separate power plant, working for a specific grid, and energy storage facilities are required.

Off-grid photovoltaics are primarily used in areas where the distribution grid does not reach. This solution is popular in the USA and Australia, where a self-sufficient mini-grid solar power plant makes it possible to build a fully functional house even in complete wilderness. In Poland, there are few areas that are not reached by the electricity grid, and the climatic conditions do not ensure such high efficiency of photovoltaics as, for example, in sunny California. For this reason, installations of this type are not so popular.

Lithium-ion batteries are most commonly used in photovoltaics. They are distinguished by their low weight with relatively high capacity and fast charging. They can be regularly discharged to below 50% without fear of failure.

Older lead-acid batteries are an alternative. They are much cheaper than lithium-ion (even by about 50%). Their weakness is their inability to be regularly discharged to below 50%, so they can only be used with large photovoltaic installations. They require adequate ventilation of the room.

In Poland, batteries from several leading brands are the most popular:

• Tesla – distinguished by efficiencies of up to 90%, the possibility of discharging even to zero and a lifetime of about 10 years,
• SMA – the brand famous for its inverters has added batteries with a capacity of up to 25 kWh to its range, designed for on-grid and off-grid operation,
• LG – a series of LG Chem RESU batteries dedicated to photovoltaics is available from the well-liked electronics manufacturer. They are distinguished by efficiencies reaching around 90–95% and a guarantee of retaining around 80% of capacity after 10 years of regular operation,
• Enphase – a manufacturer of inverters for photovoltaic micro-installations, has also introduced small batteries (capacity up to 10 kWh) with efficiencies of up to 96%. They can be safely discharged even over 95%. The company provides a guarantee of 10 years of reliable operation and maintenance of 80% capacity.
• Sungrow
• Intilion
• BYD