Illinois law requires large electric utilities, such as ComEd, to offer net metering to residential solar customers. But, it will be changing in 2025 โ possibly sooner โ and will become less favorable to customers.
Net metering determines how much credit (if any) a utility gives customers for energy they generate on their own and send back to the grid. Customers can then use those credits to offset the cost of grid electricity at other times โ such as at night.
Because of the upcoming changes to net metering, customers thinking about going solar should act now to lock in the best possible return on their solar investment. A typical customer will be about $3,500 better off under the current program than the one that will replace it. Some will save even more.
Illinois Net Metering in 2025
Section 16-107.5 of the Public Utilities Act governs net metering. Focusing just on the parts of the law that apply to most residential customers:
Subsection (d) requires utilities to give customers a credit of one kWh for each kWh sent to them, which reduces what customers have to pay on all three parts of their bill: supply, delivery, and taxes & fees.
Subsection (n) goes into effect for new customers starting January 1, 2025. It only requires utilities to give customers a credit against the supply and taxes & fees, but not delivery.
(Customers who go solar before the deadline are grandfathered. Their systems are eligible for the better program for the lifetime of their systems.)
These impending changes have a big impact for customers of Illinoisโs largest utility, ComEd.
ComEd Net Metering 2024
Consider the illustrative ComEd bill below, which is based on a real bill from February 2024.
Illustrative bill: Value of ComEd Net Metering in 2024
The figures highlighted in blue above are in dollars per kWh, and they sum to about 16 cents. By adding a solar system, a homeowner can reduce her bills by this 16 cents for each kWh the system generates.
It would be pretty amazing if her solar system produced exactly the amount of energy she needed at any given moment. In fact, this is obviously not the case: solar doesnโt produce energy at night. With this type of net metering, though, the timing of solar energy production doesnโt matter economically. Whenever she exports excess kWh to the grid, she earns a credit worth exactly what she will be charged to take a kWh from the grid. Itโs like a bank account โ if she puts $1 today she can take out $1 whenever she needs it.
ComEd Net Metering 2025
Now consider what happens if only subsection (n) net metering is available (which will be the case in 2025, and possibly sooner).
The homeowner still gets the full benefit for any kWh she produces and consumes in the moment. These are kWh that do not have to be delivered by ComEd. In fact, ComEd doesnโt even know about them! As we showed in an earlier post about ComEdโs DG rebate, it is typical for 40% of the energy a system produces to get used in the moment.
What about the other 60%, which her system sends to the grid? She now gets credits against the โsupplyโ and โtaxes & feesโ portions of her bill, but not for the โdeliveryโ portion.
illustrative bill: Value of Comed Net Metering in 2025
Our customer benefits by the same 16 cents per kWh for energy she consumes in the moment (40%), but only benefits by 11 cents per kWh for energy she exports (60%). The weighted average is 13 cents per kWh:
2024โs Illinois Net Metering Worth about $3,500
OK, thatโs the answer in โcentsโ, but how about in โdollarsโ โ as in, over the life of the system? The result depends on several (sometimes interrelated) factors:
- The size of the solar system (in kW)
- How much energy the system produces each year (in kWh)
- The share of the homeโs total electricity consumption produced by the solar system
- The share of the energy produced exported the grid
- The homeownerโs income tax rate
- How much one feels it is appropriate to discount costs or savings that happen in the future
- Utility rate inflation over time
Given all those factors, itโs not possible for us to give a single number that applies to everyone. Weโve run through many scenarios, however, and the difference is almost always between $2,500 and $4,500. The most typical answer is around $3,500. This is how much a customer stands to gain by going solar before these changes to net metering take effect.
Go Solar Today to Avoid the 2025 Illinois Net Metering Change!
As I said at the start, todayโs net metering offers the best value for potential customers. If you are thinking about solar, schedule a consultation today.
NOTES
- Average of summer and winter rates.
- On actual bills, only shows total dollars. I show the $/kWh for clarity.
- Varies by municipality. The charge in this municipality is 3.19% of the first three Delivery line items. In the per kWh rate (in blue), Iโve only included the avoidable portion (the Distribution Facility Charge).
- $0.00330 / kWh for the first 2000 kWh / month, statewide.
- $0.00628 / kWh for the first 2000 kWh / month in this municipality. This varies by municipality.
