When orienting solar panels, the rule of thumb for the northern hemisphere is that the optimal orientation for solar panels is true south. For countries in the southern hemisphere, the solar panels must be oriented to true north.
However, recently, even with no restrictions on location, building roof orientation, facing high winds, or being in a utility area with time-of-use rates, interest in east-west solar PV systems has increased.The orientation of solar panels is an important factor in generating maximum energy. Installing a solar system in the wrong direction may produce up to 30% less energy than a system oriented in the best direction.
In this article, we will look at the differences between south-facing and east-west facing solar system. And why do some people prefer oriented theirs solar panels true east-west facing?
Optimum Solar Panel orientation
In order for the solar panel to reach the peak of its generation capacity, it must be oriented in order to achieve the ideal verticality of the sun's rays, i.e. oriented in the direction that will allow the sun's rays to hit its surface perpendicularly for a length of time.
South-facing Solar panels:
Orienting the solar panels to the south allows them to get the most direct sunlight throughout the day and produce the most electricity between the hours of 10 am and 2 pm. Thus, south is the traditional direction for solar panels in the northern hemisphere.
West-facing Solar panels:
Solar panels facing west produce less electricity than panels facing south, and they do not produce electricity in the early hours of the morning. But the most important thing is that it produces the most electricity between 2 pm and before sunset.
East-facing Solar panels:
Solar panels facing east are identical to those facing west. Compared to the panels facing south, the panels facing east generate more electricity in the middle of the day, while the panels facing west generate more electricity in the morning hours. But over the course of the day, it produces less electricity than panels facing south.
East-West facing Solar panels:
Unlike south-facing panels, where peak output is reached in the middle of the day, east-west solar panels have the advantage of producing more stable output over a longer period of time.
However, in terms of total energy output, panels split between east and west may have a reduced total output (15% less than if all panels were placed facing south).
Benefits of East-West Solar PV Systems
A few years ago, unless the electricity produced by the panels was used at the time it was generated or could be stored, most people had feed-in tariffs to send electricity to the grid.
When the feed-in tariff was high, they had to increase the amount of electricity they produced to the maximum by directing the panels to the south, but with the increase in grid fees for electricity and the decrease in the feed-in tariff for solar energy, the importance of increasing self-consumption increased.
1. Self-consumption maximization
Although the total solar energy production will be lower for east-west facing solar panels, they produce more electricity during the most active times of the day for energy consumption (between 9 am - 5pm).
In order to keep up with your large consumption habits during the morning and evening hours, the east-west solar power system is most suitable for you, and it will benefit you by reducing the consumption of a lot of network energy during these periods, especially in the utility area with high time-of-use rates.
2. High Energy Production DensityThe most important advantage of east-west solar systems is the ability to install a higher density of solar panels in a limited space on flat roofs and in areas where a large amount of land is not available. The east-west solar PV system saves 10% of the area.
Since the installation of this system requires fewer structures and connection cables, the east-west solar panels save 24% of the costs required for mounting piles and steel structures.
During the summer season, when the sun is high in the sky, the total energy of east-facing PV systems is closer to the total energy of south-facing systems. Thus, the closer the solar system is to the equator, where the sun rises higher in the sky throughout the year, the greater the total energy production produced by the east-west solar panels.
3. Less Wind Loads Pressure
The east-west arrays are installed at a lower height and inclination angle than the south-facing arrays, which reduces their exposure to the north and south side winds with a small tilt angle and the aerodynamic construction of the system (a delta shape), the effects of the east and west winds are more streamlined and calmer.
4. Less Roof Loads Pressure
The other important factor is the amount of pressure resulting from installing the panels with structures on the roofs of buildings. When directing the panels to the south, we need large structures, and of course they will be heavy and cause greater pressure on the roof loads.
With the East West systems, the size of the structures is smaller, and they have a lower inclination angle. Thus, the pressure of the roof loads will be less and with a better homogeneous distribution than in the case of conventional fixed-tilt systems.
5. East-West Solar Panels and Solar Inverters
6. Less Capacity of the Interfacing Power Substation
When solar PV systems are connected to the grid, the connection is usually done by a power transformer. For example, with a one megawatt peak system, a 700 kVA transformer is required to connect the south-facing system to the grid.
As for the system with the same size but divided into 0.5 MW peak to the east and 0.5 MW to the west, in the morning it will mainly generate about 65% of the power capacity, which means that instead of needing a 700 kVA transformer to integrate to the grid, we can use about 450 kVA to integrate half of the half side of the system, the same story in the evening.
so this means that the same energy can generated at lower power.
Favoring East-West solar PV systems
When we talk about photovoltaic systems, we're not just talking about energy and how much energy we get; sometimes we talk about many other technical issues, including power, electricity, current, voltage distortion, and power quality.
At the beginning of renewable energy, we were very supportive. We need photovoltaic systems connected to the grid, but now we need to optimally plan them because sometimes those systems cause some distortion to the grid.
So in order to assure the smooth integration of the grid without high distortion because of the solar radiation fluctuation. At the same time ensure that we produce the same energy but in a different way in a much better way, east-west solar PV systems is one of these way.
East-West vs. South Solar Panels: What Is the Best?
The answer is it depends. It depends on how you use your electricity, and what time of day your electricity demand is highest.
Solar PV systems facing south will produce the most kilowatts over the course of a day. As a result, if you have an off-grid solar panel system, pumping system, or any current-based system, go with the south-oriented systems because you need high current to charge the battery. As long as you have high current, you have a higher charging rate.
But if you have a grid-tied solar panel system and your utilities charge you a variable rate based on the time of day, you might be better off using an east-west orientation if your electricity demand is high in the morning and evening hours.