# Economic Analysis of Potential Secondary Use of Batteries from Electric Vehicles
## 3 Economic Analysis
### Important Investment Equipment  
For the proper functioning of the battery storage, not only the batteries themselves are needed but also a substantial number of other devices. These are mainly DC/AC inverters, SCADA remote control system, transformers, storage containers and air conditioning. In the case of small repositories at dealers, it is necessary to include the fast charging station. For the batteries to be connected to the power system, their DC/AC inverters must first be used to change the nature of their energy from DC to AC. A modern three-phase inverter with an output of 50 kW from the manufacturer Kaco, whose supplies, including an integrated control system, was chosen for this calculation model. It can be connected to the superior system of the entire dispatching via USB or LAN port. The device is stored in a separate cabinet measuring 140 cm \(\times\) 84 cm \(\times\) 36 cm, which can be placed inside or outside the universal container. According to [32] the market price was set at \(\xi\)3696. Universal storage containers were selected using the company Algeco s.r.o., which builds modular buildings in the Czech Republic with a variety of uses. Two options were considered for this model. The first larger container with dimensions 601 cm \(\times\) 244 cm \(\times\) 260 cm for the price of \(\xi\)2900. The basic electrical installation, including the switchboard, costs \(\xi\)192, air conditioning \(\xi\)958 and fire protection, including fire alarm, approximately \(\xi\)3300. Approximately 28 batteries can be accommodated in this container so that there are sufficient gaps between the batteries for airflow and space remains even for a small background for air conditioning, server and computer. The second smaller container with dimensions of 299 cm \(\times\) 244 cm \(\times\) 260 cm for the price of \(\xi\)1920. The price of electrical installation and air conditioning remains the same, only fire protection costs less--about \(\xi\)2000. Professional installation of batteries and the connection of other devices inside the battery storage was evaluated using the hourly rate of installation on electrical equipment for 13 EUR/hour [33]. It will take approximately 1 h to install one battery and about 24 h to install the entire container, including inverters and support devices. The small, decentralized battery storage will belong to the subcategory of production modules A2 (up to 100 kV) or the subcategory B1 (up to 1 MW). All manufacturers from category A2 are connected directly to low voltage. For B1, it depends on the local conditions of the distribution network, and this source can also be connected to low voltage. Due to this, it will not be necessary to install an expensive transformer at the expense of the car company. In the case of a large central repository, the installed capacity will certainly exceed 1 MW, due to which it will fall into the subcategory of production modules B2. This category is only connected to high voltage lines. For direct connection to the mains, it is necessary to change the low voltage inside the device (400 V) to a high voltage (22 kV). Transformers from RTS a.s. with an output of 1000 kVA costs \(\xi\)13,700, including installation. Regular annual inspection and maintenance cost \(\xi\)420, while as part of the simplification of the model, it is paid once during the procurement. According to the Code, PSS certification is performed regularly at a time interval of 4 years. When determining the price of FCP certification as battery storage, it was found that there is no exact price list for any company yet. However, one of the interviewed experts set the price at \(\xi\)1950. The fast-charging station was selected to have a communication interface for remote management and to be suitable for public use. The second condition would allow for the drawing of procurement subsidies from the European Union up to 55% of eligible costs. The EVlink Parking station charging station with an output of 2 \(\times\) 22 kW was chosen for this model.