The photovoltaic power plant at the Parabel site is connected to the site's own consumption. This means that the energy from the sun is always first and foremost consumed in the company's operations or stored in the Amvolt Battery Container and only the surplus is sent to the distribution grid.

The three modes of use of the system change continuously and automatically during the year. In the first mode, the production from the sun is higher than the actual consumption of the site. Excess production is stored in batteries and any surplus goes into the distribution system. In the second mode, the solar panels produce less than the current consumption of the campus and the difference is made up by the batteries so that there is almost no draw from the grid. In the third mode, there is minimal or no production from the sun, the batteries are discharged and all energy is therefore drawn from the grid.

The transition between these modes is completely automatic and without user intervention.

All battery, inverter and power technology is housed in a container designed for year-round operation. In addition to increased fire resistance and insulation, it is equipped with an autonomous heating/cooling unit to ensure an optimum interior temperature between 15 and 25 °C. 

The annual savings due to the photovoltaic power plant should be up to about CZK 400,000 according to the price of electricity.

Technical Description

The power plant consists of three basic units:

Solar panels
• 270 panels of nominal power 270 and 375 W
• 28 panels are placed vertically on the façade to ensure increased electricity production in winter, when the sun is low above the horizon
• Total power plant output is 90,75 kWp

The total power value indicates the peak kW that the power plant can deliver under optimal conditions – relatively cool weather, direct illumination, and brightness. In practice, however, the value of production in kWh is much more important.

In the case of the implementation of this PV plant, annual production of 100–110 MWh of electricity is expected.

Inverters (voltage converters) and optimizers
• 3 inverters with a total output power of 80 kW
• Optimizers for each pair of PV panels

Optimizers and inverters ensure the highest possible efficiency of converting solar radiation into direct current (solar panel) and then alternating current (inverter output), usable for normal operation. In the event of an accident – for example, a fire – the system with optimizers then ensures a safe voltage of max. tens of volts on the part of the power plant between the inverter and the PV panel.

Battery system
• Amvolt Battery Pack – Non-flammable and non-explosive LFP batteries with a usable capacity of 105.6 kW
• 3 inverters with a total charging/discharging capacity of 36 kW

For the correct operation of the entire system, it is important to measure the energy at the entrance to the building. The current and voltage measuring transformers on the supply cable give the inverters the information on whether the batteries need to be discharged (a mode where the consumption is higher than the PV production) or charged (the electricity consumption is lower than the current production).

In addition, the Amvolt battery system with Victron Energy inverters is able to act as an island (backup) for part of the site. In the case of the Parabel operation, the administration and storage areas are completely backed up. In the event of a prolonged power outage, the distribution of products and the company's facilities will therefore not be compromised in any way.

General installation contractor: ENERG-SERVIS a.s. + Tomas Vocilka (Asolar s.r.o.)