Types of solar power stations

Types of solar power stations

There are two main types of solar stations: –

• Off Grid stations
• On Grid Stations connected to the governmental electricity grid

Off Grid

We depend on the Sun’s energy at 100% to provide all the electricity the facility needs because there is not definitely another alternative to the energy supply. The station is also designed in a way that includes providing all the needs throughout all seasons of the year . It is advised to resort to this system which can dispense in any alternatives of energy during Long periods of bad weather, as the support is not available from the government network.

When we design this solar station system, consideration must be given to providing all of the following information:

• Electric loads, i.e. all devices that operate with electricity and their number
• Duration of work hours for each of these loads separately
• Day and night time for the load operation
• Geographical location of implementation
•  There is a program in the design stage of the station on the computer through which the previous data is formatted and calculated accurately to determine the main components of the station, which are four: –

• Solar panels

Where the size, number of panels and the angle of inclination are determined according to the program of calculating the productivity of cells. It is noted that the program takes into account when entering data the geographical location to determine the amount of annual solar radiation available for that place.

• Inverter

Here, the inverter has nothing to do with the inverter with a geographical location or with the ability of the panels, but the size of the inverter is determined by knowing the maximum limit of all loads when operating them at the same time, taking into account that it must be of the type that gives a capacity of 3 times the same (Surge Power) when starting the motors.

• The batteries

There is a program for designing batteries that enables us to obtain accurate information about the length of daylight in each month, in each city in connection with the maximum productivity of the one kilowatt of cells, through drawing a curved line of daily loads in which the AutoCAD program is used. Thus we obtain the required number and capacity of the battery storage appropriate for use in The station.

• Charging regulator

It is the device that regulates the electrical voltage issued by the cells before it reaches the storage batteries so that the batteries are preserved and the completion of the charging process is completed in an optimal way.

Advantages of the (Off Grid) stations

• When the governmental network is cut off, the solar station will not be affected.
• When the supply of electricity networks is not available in remote areas, and the alternative is not available. Also when the price of such as gasoline and diesel increases, it will be the best solution.
• Through it, a lot of infrastructures with their extension of cables, adapters, and pressure towers are dispensed.
• No need for governmental licenses and permissions.
• Within one day, it is possible to implement a small station and run loads on electricity, which is thus the fastest energy supply.

Disadvantages of the (Off Grid) stations

• When talking about central cooling or heating systems and factory operating, we stand facing a non-economic system that is not sufficient to provide energy for these large loads.
• As we always need to provide a reserve of energy consumption throughout the year that covers the worst months of solar brightness, then an electricity surplus occurs in some months as a by-product that cannot be taken benefit of.
• We design stations according to criteria that take into account the worst months of solar brightness, but we cannot foresee any catastrophic climatic events that may lead to the station stopping of production for up to a week, for example, although they are rare weather conditions, but when we encounter them, they are definitely catastrophic.
• During the so-called charging and discharging cycle of the batteries there is a large waste of electrical energy up to 30% This is just for charging and discharging that has nothing to do with consumption or efficiency. In addition to that, there is a waste about 5% as it may be caused by the charging regulator and another waste about 5% caused by the inverter and thus the total loss reaches 40% of Energy compared to ON Grid stations.

Stations connected to the government electricity grid (On Grid) )

The solar power station is linked to the government electricity grid, exporting the surplus to it, or selling it according to a contract whose terms are agreed with the electricity company. The station is designed on a basis that allows it to produce the highest annual return until the slope angles of the panels are set to achieve this goal regardless of the balance of the annual electrical production for that. Many are looking for the possibility of using such stations as an investment project that will bring them profit, as well as achieving self-sufficiency and avoiding energy crises.

The station productivity depends on the number and efficiency of the solar panels used, the angle of inclination and also the capacity and efficiency of the inverter besides the geographical location.

How to design stations (On Grid)

• The solar cells absorb and collect the sun’s energy and produce a continuous electric current (DC)
• This constant current travels through the inverter that converts it to alternating current 220 volts (AC)
• That (AC) electrical current comes out from the inverter to the cables during the day flowing to the national network through the reciprocal electricity mete

Station Features (On Grid)

• This system of projects, according to feasibility studies, represents a profitable investment in the long run. Therefore, when contracting with the station owner, the Electricity Company will purchase all the energy generated by the panels for a long period, unlike other projects that suffer from market fluctuations.
• These stations do not need batteries, which reduces the costs of the station and the expenses of operating and maintenance
• Compared to traditional power stations, the photovoltaic power stations are 90% less than that cost besides they do not consume with them water, oil or gas, and more they do not require workers’ wages to operate the station.
• As for residential facilities, if the customer complains of a very high level of electricity bills and does not have enough space to establish stations that cover his need, even entering the savings process by constructing a station, that is less than his consumption, that means that he will be able to reduce the burden of those bills over time.

Station Disadvantages (On Grid)

• In the event of a power outage issued by the government network, the facility that owns the station connected to the network will suffer from a power outage automatically even though the station may still be producing due to the presence of a reflector connected to the network, disconnecting automatically when the power is cut off.