For those of you who want to be energy self-sufficient and off the grid, you will ask is: how many solar panels will I need to go completely off the grid? The answer to this question involves a number of factors including your home’s energy consumption, your location’s sunlight conditions, and the performance of your panels. In this article, we’re going to walk you through how to figure out how many solar panels will meet your needs and help you build a system that provides consistent, stable power for your home.
What is “Off-grid”?
The term “off-grid” is commonly used to describe those who opt to keep their homes independent of the national grid. While traditionally, one may view off-grid living as a return to a strenuous lifestyle, it is anything but.
Off-grid living is the autonomous creation and utilization of natural resources, such as self-produced electricity, natural gas, and water through solar energy systems. This self-sufficient lifestyle is especially popular, even a necessity, in areas where access to traditional government-provided utilities is difficult.
But solar power is not only being adopted by homes in remote areas. A growing number of environmentally conscious, forward-thinking individuals are choosing to live off-grid, looking to save money on their monthly utility bills by reducing their impact on the environment.
What is an off-grid solar panel system?
An off-grid solar panel system is an independent power system ,in which power is generated without being dependent on the national grid. An off-grid type of solar panel system basically uses majorly photovoltaic panels to change sunlight into electrical energy and transfers that energy to the load through solar charge controllers and inverters. During sunny conditions, the off-grid solar system supplies power to the load via the solar panels while simultaneously charging the battery bank. If the sun is not available at noon or night, the solar system supplies power to the load from the battery bank.
Want to delve into the details regarding off-grid solar systems? Read our previous detailed explanation article. Click to read
How many solar panels do I really need to have off the grid?
The number of solar panels needed for off-grid depends on your daily consumption, average hours of sunshine in the area where you are living, and the conversion efficiency of the panels. According to the Energy Information Administration, the average monthly electricity use by a household in any given area is about 900 kWh, or about 30 kWh per day, but many off-grid homes seek energy efficiency and consume less.
A typical photovoltaic panel is rated at 300 watts and can produce approximately 1.5 kWh of electricity per day in areas receiving five peak hours of sunshine per day, which may be the case in some parts of California or Texas. The number of panels required can be calculated by the following formula:
Number of Panels Required = Daily Energy Consumption \ Daily Electricity Generation per Panel
Suppose your house uses an average of 30 kWh of electricity per day and the solar panel generates 1.5 kWh of electricity per day. You will then require roughly 20 panels to power up your house. Needless to say, this could be different based on peak sunshine hours where you reside. If the area gets very little sun, more panels will be required to get that amount of energy.
Following is the table that gives the approximation of how many solar panels may be used for different levels of energy consumption and hours of sunlight:
| Household energy consumption (kWh/day) | Peak daylight hours (5 hours) | Peak daylight hours (3 hours) | Quantity of 300W solar panels required (5 hours) | Quantity of 300W solar panels required (3 hours) |
|---|---|---|---|---|
| 15 kWh/day | 5-6 panels | 8-9 panels | 10-12 panels | 15-17 panels |
| 30 kWh/day (average household) | 20 panels | 25-30 panels | 20 panels | 25-30 panels |
| 45 kWh/day | 30 panels | 40-45 panels | 30 panels | 40-45 panels |
This means that for a household with an average consumption of 30 kWh/day, about 20 solar panels will be required in a region that has 5 hours of peak sunlight. For locations with only 3 hours of sunlight per day, about 25-30 panels may be needed to generate the same amount of energy.
How to Calculate the Number of Solar Panels Required
Everyone has a different energy consumption, per person or household, so it is impossible to determine standardized criteria on how many solar panels a house would need to take it completely off the grid.
There is a simplified means to calculate how many panels would be required:
you need to look at your electric bill to get an idea of your monthly energy consumption. After finding out how much electricity you consume in a month, multiply the average daily peak sunlight hours by 30 to estimate the total peak sunlight hours per month in your area.
Then, divide the total monthly electricity consumption by the total peak sunlight hours per month to get the average amount of electricity needed per day.
For example, the average electricity consumption of a U.S. household is about 893 kWh per month, and using the monthly peak sunshine hours in sunny Texas as an example, the calculation is as follows:
893 kWh/135 = 6.6 kWh
After getting the average amount of electricity needed per day, the next step is to convert kWh to watts, which can be done by multiplying by 1000.
6.6 kWh x 1000 = 6,614 Watts
To determine the number of solar panels, take the total wattage required and divide it by the quantity of electricity each panel can provide per hour. Assuming that solar panels are capable of producing an average of 250 watts of electricity per hour, to calculate the number of solar panels for a 300-watt system, one gets:
6,614 Watts / 300 = 22
Therefore, a Texas home that consumes about 893 kWh of electricity per month will require roughly 22 solar panels to satisfy its electricity demand.
How much do I have to invest in an off-grid solar power system?
The cost of the off-grid solar power system would depend upon a number of factors relating to the size of the systems, quality of modules, the cost of installation, choice of batteries, quality of solar panels, etc. For the average off-grid home with moderate energy consumption, an investment of approximately $25,000 to $35,000 will be required to purchase a complete system. However, for homes with higher energy consumption, the expense of a larger system may be significantly higher.
Now that you should have an idea of the entire process regarding how to calculate the quantity of off-grid solar panels a building will require, if in an off-grid system application, please refer to our solar products and our solar experts also will give you a well-thought-out plan.