The appropriateness of a particular orientation of the panels in relation to the points of the compass depends on the objectives and characteristics of each individual case. This article provides a detailed analysis of the orientation of solar panels as part of a solar power plant to the east and west simultaneously, including the identification of their advantages and characteristics. Although the installation of solar modules facing south is the most common in Ukraine and is efficient in terms of annual energy production, sometimes the east-west orientation can be more promising under certain conditions. Let’s take a closer look at this case study.
Photovoltaic panels work best when the sun’s rays hit their surface at an angle of 90 degrees. Therefore, in cases where it is desirable to maximise energy production and it does not matter when it is produced during the day (for example, when selling electricity at a green tariff), it is best to orient the panels to the south, as this allows the panels to be installed at such an angle that the sunlight falls on them perpendicularly.
However, in cases where the time at which the solar panels produce energy is critical, the choice of PV orientation becomes less obvious. For example, if electricity is only consumed in the afternoon, it is advisable to place the panels facing west. Of course, production will be lower at 12 o’clock, but from 4 o’clock the panels will receive more direct sunlight, which will increase production. So, after 18 hours, the south-facing panels will effectively stop working, while the west-facing PV panels will still be generating electricity.
Let’s take a more practical example: many businesses operate at 12 noon, 8 am and 6 pm. Accordingly, the company consumes electricity throughout the working day. And if this consumption is evenly distributed throughout the day, then replacing their own electricity consumption with south-facing panels will only be good during the day, while in the morning and evening they will be using more expensive electricity from the grid. By using a combination of east- and west-facing panels in this case, the company will have an evenly distributed replacement of electricity consumption throughout the day, which will significantly reduce its electricity costs.
Of course, there is no one-size-fits-all solution for every situation. And different solutions will be optimal for different conditions. We have analysed some cases where the east-west system has an advantage due to its design features and better generation in the morning and evening hours.
Another major advantage of using east-west systems, in our opinion, is the ability to install a much larger number of PV modules, and therefore more power, on the same free surface. This advantage is due to the fact that, when installing south-facing panels, their angle of inclination is quite large (from 25 to 35 degrees) because, as mentioned above, this optimises their operation. However, in this case, adjacent rows of panels can cast shadows on each other, which, as you can imagine, reduces their efficiency. To avoid this problem, gaps are made between the rows of panels to prevent them from shading each other. When using the east-west system, the tilt angle of the panels is usually no more than 15 degrees. As a result of the design features, the problem of shading is cancelled out. As a result, almost twice as many panels can be installed in the same area using the east-west system.
Let’s imagine a solar power plant with a total rated power of 50 kW of panels, this power is generated by direct current, hereinafter referred to as DC (direct current), because the panels generate direct current. In addition, all these panels are connected to a solar inverter with a rated capacity of 50 kW, whose output is alternating current, or AC, because, as you know, the function of the inverter is to convert direct current into alternating current, which is the most commonly used in electricity grids.
In ideal weather conditions, the panels will deliver their maximum power and we will get a maximum of 50 kW from the inverter output. Unfortunately, ideal weather conditions, when they exist, are very rare. For example, on a less sunny day, such a station will have an output of 40 kW instead of 50 kW. Therefore, in order to ensure acceptable power generation at the inverter output, more panels are installed, if space permits, so that the rated DC power is greater than the rated AC power. This ratio is called the DC/AC ratio, and typically economically viable values of this ratio are between 1.2 and 1.3. This means that for the more efficient operation of our imaginary station, it is better to install panels with a total rated power of 60 kW, in which case the DC/AC ratio will be 60/50=1.2.
In fact, for the efficient operation of solar stations using the east-west system, our engineers consider it appropriate to have a DC/AC ratio of around 1.3. This allows you to collect more energy during the day.
Thus, the use of combined east-west orientation of solar panels is a very effective solution for some companies that need to replace electricity consumption, which is evenly distributed throughout the working day, with cheaper solar energy due to a number of advantages.
Our company has many years of experience in the installation of various solar power systems. You can be sure of the quality of our services and the reliability of the stations we install, and above all that the solution we propose will be the one that best suits your needs and parameters. If you have any questions about the specifics of using East-West PV power plants, please contact Avenston. We will be happy to advise and assist you in making the most of your project.