How to calculate solar panel requirement?

The thumb rule for determining the solar plant capacity is to divide the total units consumed mentioned in the electricity bills by 120.

Understanding the Thumb Rule for Solar Capacity Calculation

At the heart of solar capacity planning lies the thumb rule: a simple yet effective starting point for homeowners. This rule suggests dividing your monthly electricity consumption, as stated on your utility bills, by 120 to determine the basic capacity in kilowatts required for your solar plant. For instance, a monthly usage of 600 units translates to a solar capacity need of 5 kilowatts (600 units / 120).

Beyond the Basics: A Holistic Approach to Solar System Design

However, this method is not completely accurate and there are other factors that need to be considered before finalizing the capacity of the solar plant. While the thumb rule provides a preliminary estimate, it's merely the tip of the iceberg. These factors include the number of occupants in the house, the size of the house, and the type of electrical appliances used.

To calculate the exact capacity of the solar plant required for your home in Delhi, follow these steps:

Step 1: Collect Your Electricity Bills

The first step is to collect your electricity bills for the past 12 months. This will give you an idea of your energy consumption and the average units consumed per month.

Step 2: Calculate the Monthly Average

Add up the total units consumed in the past 12 months and divide it by 12 to get the average monthly units consumed.

Step 3: Determine Your Load Profile

The load profile refers to the amount of electricity you consume during different times of the day. During the day, the solar panels will produce electricity, and any excess power will be stored in batteries. At night, when the solar panels are not generating any power, the electricity will be drawn from the batteries.

Step 4: Consider System Losses

It is important to consider system losses when calculating the solar plant capacity. System losses occur due to factors such as wiring resistance, inverter efficiency, and temperature. A general rule of thumb is to add 15% to 20% to the total capacity to account for system losses.

Step 5: Choose the Solar Panel Size

The final step is to choose the appropriate size of the solar panels. Solar panels are available in different sizes and efficiencies. It is important to choose the size that meets your power requirements and fits your budget.

An Alternative Method for Higher Precision

For those seeking precision, another method involves calculating your average daily energy consumption from your annual electricity bills and multiplying this by the peak sunlight hours in your area. This approach considers the intensity of sunlight available to power the solar panels, providing a refined estimate of the required capacity.

1. Gather Your Electricity Bills: Start by collecting all your electricity bills from the past year.

2. Calculate Your Average Daily Energy Consumption:

• Add up the total units of electricity consumed over the year.

• Divide this total by 365 to get your average daily energy consumption in kilowatt-hours (kWh).

1. Determine Peak Sunlight Hours:

• Understand that peak sunlight hours are the period each day when solar radiation is strongest.

• Note that in Delhi, the average peak sunlight hours are about 5.5 hours per day.

1. Calculate Solar Power Plant Capacity:

• Multiply your average daily energy consumption (from step 2) by the average peak sunlight hours in Delhi (from step 3).

• This calculation gives you the size of the solar power plant you need in kilowatts (kW).

1. Example Calculation: If your average daily energy consumption is 20 kWh:

• Multiply 20 kWh (daily consumption) by 5.5 hours (peak sunlight hours).

• The result indicates a required solar power plant capacity of approximately 4 kW to meet your energy needs.