Now that your solar system is producing, you might be wondering how the power flows from your panels and on to the grid. The most common questions we get are about tracking the kilowatt hours produced, why the numbers from Xcel Energy do not always match, and how the solar credits get used up.
When your panels produce power, they go through your production meter first. This meter is owned by the homeowner and starts at zero when the system is connected to the grid. It shows cumulative power produced. If you are on a program such as Xcel Solar*Rewards, the Made in Minnesota Solar Incentive Program, or an SREC program (also known as solar renewable energy credits), the production meter is where the total annual kWh credits will be electronically read. The production meter is not affected by usage from the homeowner.
Next, your solar power runs to your home electrical panel and is used by any electrical devices in your home that are on at the time. If you use all the power being generated at the time your solar is producing, the power never makes it to your utility bi-directional meter. The utility cannot track the used power from your solar system. To them it would be the same as if all the power was shut off in your home.
If you generate more than you use, that power goes on to the grid. The bi-directional meter keeps track of the credits and, when you are using more than you produce, you use up those credits.
Every month, the credits roll over unless you request a credit check from the utility. Some utilities have a true up period where you must take the credits as a payment. This varies by utility provider and region, so it is best to call your utility to see how they handle credits.