How to Calculate Power Consumption?

 

Power consumption is the most important statistic to consider when determining the solar setup you want for your system. Depending on how much power your system uses throughout the year, you can get a solar power setup that gives you all the energy you need. Power consumption also determines the number of batteries, solar panels, and inverter types.

 

First Find Out the Power Rating

 

First thing is to make a list of all the electrical items that your system would be using:

• Lights (LED, incandescent, etc) 
• Appliances (Fridges, ovens, toasters, etc) 
• Electronics (TVs, computers, chargers, etc)
• HVAC (Heaters, air conditioners)
• Pumps (Water, heat, wells)

Once you've determined all the products that use electricity in your system, you will need to find the wattage of each of them. This can be done through online research or by looking at the label on the item.

 

Calculate the Daily Energy Use

 

Power consumption is measured in kilowatt-hours (kWh). You must use the formula:

• Energy (kWh)= Power (W) × Hours Used per Day / 1000

Example. ​If you have a 1000-watt air conditioner running for 5 hours a day the power consumption would =1000 W × 5 hours / 1000​ = 5 kWh/day

Once you figure out the power consumption of every item, sum it all together. This will give you the total daily energy usage for your system.

Keep in mind that certain appliances are used seasonally. Heaters are used in the winter while air conditioners are used in the summer.  Keep this in mind when figuring out your total energy usage and when determining your solar needs.

 

What Else do I Need?

 

You must account for battry storage in your off-grid systems. Each battery has a capacity in kWh and you may need multiple of them to cover your needs. Each operates at an efficiency loss of around 80-90% so keep this in mind when calculating your storage needs.

You must regularly track and monitor your energy usage. This is done using an energy monitor or smart meter so that your can observe it in real-time. This is a must have in off-grid sysytems as you will need to manage both your energy consumption and generation.