Rooftop solar power systems (PLTS) are increasingly popular as an energy-efficient and eco-friendly solution.
However, before deciding to install solar panels at your home or business, you need to know how to accurately calculate the required system capacity to ensure an optimal return on investment and that your electricity needs are met.
Solar installation services can also assist you in determining the right system capacity for your needs.
Why Is Calculating Solar System Capacity Important?
Arbitrarily determining solar panel capacity can lead to two main risks:
a. Insufficient Capacity (Under-sizing)
The generated power is insufficient to support daily loads, leaving you fully dependent on the grid (PLN).
Ultimately, the solar installation feels futile since you still rely on grid electricity. The payback period also becomes longer.
b. Excessive Capacity (Over-sizing)
Initial investment costs balloon without a commensurate gain in cost efficiency.
Steps to Calculate Solar Panel Requirements
The process of calculating solar system capacity is based on total daily energy consumption, measured in Watt-hours (Wh) or Kilowatt-hours (kWh).
1. Calculating Total Daily Electricity Consumption
The first step is to list all electronic appliances, their power ratings (Watts), and their daily usage duration. For example: LED lights (5 units): 50 Watts x 10 hours = 500 Wh 1 HP AC unit: 750 Watts x 8 hours = 6,000 Wh Refrigerator: 150 Watts x 24 hours = 3,600 Wh TV & WiFi: 100 Watts x 10 hours = 1,000 Wh Total Daily Load: 11,100 Wh (equivalent to 11.1 kWh)
Quick Alternative: You can also check your average monthly usage on your PLN electricity bill (e.g., 330 kWh per month) and divide it by 30 days to arrive at an average daily consumption of approximately 11 kWh.
2. Factoring in Peak Sun Hours (PSH)
Peak Sun Hours (PSH) refers to the effective duration of sunlight intensity received by solar panels per day.
In Indonesia, the average PSH duration ranges from 3.5 to 4.5 hours per day, depending on geographical location and weather conditions.
3. Factoring in System Efficiency (System Losses)
Solar power systems experience power losses due to inverter efficiency, cable resistance, and heat affecting the solar panels. The standard efficiency value commonly used is 75% – 80% (a correction factor of 0.75 – 0.80).
4. Battery Requirements
For a load of 11,100 Wh, a battery is necessary, at least for nighttime use.
If the system is used only during the day, a battery is not required.
Batteries can also be considered as a backup power source during grid outages. ## Formula and Example Calculation for Solar Power System (PLTS) Capacity Once you have the data for daily consumption, peak sun hours (PSH), and system efficiency, use the following formula:
Required PLTS Capacity (Wp) = Total Daily Consumption (Wh) / (PSH (Hours) x System Efficiency)
Example Calculation for PLTS Capacity Suppose your home's total daily consumption is 11,100 Wh, your location has an average PSH of 4 hours, and the efficiency factor is assumed to be 0.80: PLTS Capacity = 11,100 / (4 x 0.80) = 11,100 / 3.2 = 3,468.75 Wp
Thus, the estimated requirement is a PLTS system with a capacity of approximately 3,500 Wp (3.5 kWp).
Determining the Number of Solar Panel Modules and Supporting Components Based on the total power calculation, you can determine the number of solar panel modules and the specifications for supporting components.
1. Calculating the Number of Solar Panel Modules
If you choose solar panels with a capacity of 550 Wp per unit, then: 3,500 Wp / 550 Wp per unit; the estimate is that you need 7 solar panel modules.
2. Selecting the System Type and Components
a. On-Grid
Connected to the PLN grid without batteries. Highly suitable for saving on electricity bills during the day.
b. Off-Grid
Uses batteries to store power. Requires additional battery capacity calculations to meet nighttime needs.
c. Inverter
Choose an inverter capacity that matches or slightly exceeds the total peak wattage of the solar panels (minimum capacity of 3.5 kW–4 kW).
Important Considerations Before Installing a Rooftop Solar Power System (PLTS)
a. Roof Area and Orientation
Ensure the roof has a shadow-free area and faces the right direction to capture sunlight effectively. ...maximum.
b. PLN Power Capacity
Adjust the inverter capacity so that it does not exceed the installed power limit set by PLN when using an On-Grid system.
c. Roof Structural Strength
Check the load-bearing capacity of the roof structure before installing solar panel modules and mounting brackets.
Conclusion
Accurately calculating the required capacity for a solar power system (PLTS) is a crucial step in ensuring the system operates optimally and efficiently.
By understanding total daily consumption, sunlight exposure duration, and equipment efficiency factors, you can plan a solar panel investment that perfectly suits your home or business energy needs.
If you have any doubts, consult a technician or a professional solar power system installer to ensure the planning and installation are safe and effective.
Interested in a consultation regarding solar power system installation, including capacity calculations? Consult with Batari Energy via this link!