IRENA - Istrian Regional Energy Agency

IRENA installed one small PV solar plant of 6kW that will produce electrical energy solely for the power supply of one building . Plant will be placed in the area of Čepić field, or more precisely on the roof of elementary school Ivan Goran Kovačić, Čepić. Annually, plant will produce around 7,500 kWh of el.en. This building was chosen because is ideal for placement of this kind of plant; it has flat roof where you can easily place the solar panels and it annually spends around 9.775,00 kWh of electric power, what means that implemented solar plant will be able to cover about 70-80% of electricity needs of proposed building. Also, thanks to the fact that plant will be placed on the school, it will have a big visibility and demonstrative purpose.

Pilot investment: 

• PV solar plant of 6kW
• Elementary school Ivan Goran Kovačić
• Budget: 24.000 EUR

Main components:

1. Photovoltaic modules,
On the roof of the building 24 PV module units of total combined power of 6kW will be on mounted in 3 lines, placed to south east with the inclination of 30.

2. Grid power inverter el.en. (DC / AC inverter)
Most complicated part of the system probably are two power inverters. Grid power inverter converts DC power from PV modules into usable AC power and has integrated electrical and voltage protection on DC and AC side.

3. Bidirectional power inverter (AC / DC and DC / AC) and batteries,
Bidirectional power inverter which uses produced el.en. according to consumers’ needs or storages surplus of produced el. into the batteries. Inverter can work in two modes;
Normal mode - in the case where we have power from public network, inverter supplies the consumers with power from the public network and from solar power. Or in simpler terms, when solar plant is not working building will use the electricity from public network, when solar plant is in functions then the building will use the produced electricity and in addition will charge the batteries, depending on their condition. Just in extreme cases when plant is producing more than building can spend and if batteries are fully charged, produced energy would then be given to the public network. Off course for free.
Backup power mode- in case of the failure of public network, inverter will provide important electricity consumers with the energy stored in the batteries.

4. Main distributor cabinet (GRO)
Main distributor cabinet where is placed the equipment for protection and distribution of electrical installations. Also its represents the connection point of customers' installations, installation of PV power plant and external public network. In the case off power plant malfunction, it will be possible to manually unplug the plant from the network and the customer.

5. Cabinet for accommodation of active power equipment
Cabinet will be used for accommodation of active power equipment; inverters, batteries and equipment for protection and management of the PV power plant.

6. Surveillance and communication equipment,
Plant will have integrated surveillance and communication equipment, respectively microcomputer / communication unit with web interface-central circuit control and monitoring systems that provides monitoring and management of plant operation. This unit will monitor and visualize the condition and operation of all individual device powers and the possibility of optimization of energy production and consumption within the system.

7. External lightning protection system - LPS.
Upgrade of the external LPS – lightning protection system, will assure maximal protection of the power plant and the school building.