How is solar energy made and used in your home?
Well, the science behind solar technology is quite fascinating; however, the basic premise is quite simple.
- Solar panels, containing solar cells, are installed on your roof onto mounting racks.
- On sunny days (and even on cloudy days), the sun shines light on the solar panels.
- The solar cells convert sunlight into electricity in DC (direct current) form.
- The DC electricity is then converted into AC electricity by an inverter, which is installed somewhere in or around your home (typically the basement, garage or outside). AC is the form of energy used in your home to power all your lights, appliances and other household gadgets.
- Any excess energy you don’t use is sent to your utility company and measured via net metering.
- You get credit from your utility company for the electricity you produce.
- On rainy days and at night when the sun is not shining, you continue to receive power from your utility company, but you can utilize the excess energy you produce during the day.
- If you produce more electricity than you actually use, you build up credits with your utility.
Sunny Day vs. Cloudy Day
In this basic example, you can see how a solar system can benefit your electricity bill. Solar power production varies, depending on a variety of factors, including the size of the system, the season and each day’s weather conditions.
Electric power is measured in watts. 1 kilowatt (kW) is equal to 1,000 watts, for example, ten 100 watt light bulbs. Electric energy is the power produced over time and is measured in kilowatt hours (kWh). One kWh is the amount of energy used by those 10 bulbs in one hour. It is the measure used by your utility company to bill you for your electricity usage.
On a sunny day, if you produced 30 kWh of energy, but only used 15, the extra 15 would travel back to the electrical grid to be distributed by your utility company as needed. You would “bank” a credit of 15 kWh in your account which could be used on a day that you don’t produce as much electricity.
On a cloudy day, you may only produce 5 kWh, but still use 15. Therefore, you would need to take 10 kWh from your utility company for that day. Since you overproduced on the sunny day and have a credit of 15 kWh, you could take in 10 kWh from the utility at no cost on the cloudy day. And you would still have a credit of 5 to use on another day.
Don’t worry. You don’t have to do any of these calculations yourself. Your solar system works with your utility company to do these calculations automatically and the utility adjusts your electricity bill accordingly.
At the end of the billing cycle, your utility company will send you a bill which will reflect:
- What you owe them for using more electricity than you produced, OR
- A credit for using less electricity than you produced
In this example, at the end of this hypothetical 2 day billing cycle, you would receive a credit for 5 kWh from your utility company.
We hope this solar energy information in this simplistic example was helpful.