Updated: August 22, 2026 · Estimated read time: 10 minutes
Solar panels can produce the same electricity whether you use that power immediately or send it back to the electric grid.
But financially, those two kilowatt-hours may no longer be worth the same thing to a new Illinois solar customer.
That's because Illinois changed how net metering works for new residential and small-commercial solar systems beginning January 1, 2025.
For homeowners considering solar in 2026, the change makes one concept increasingly important:
Using more of your own solar electricity while it's being produced.
That's known as solar self-consumption.
And understanding it can help you make better decisions about system size, batteries, EV charging, appliances—and whether solar makes sense for your home at all.
Quick Answer
For new residential and small-commercial solar customers in ComEd, Ameren Illinois, and MidAmerican territory interconnected on or after January 1, 2025, traditional full-retail net metering is generally no longer available.
Newer customers generally receive supply-related credits for qualifying excess solar electricity sent to the grid rather than credits covering both electricity supply and delivery.
That means:
Electricity your solar panels produce and your home uses immediately can be more valuable than electricity you export to the grid and later replace with grid electricity.
But the exact economics depend on your utility, rate plan, electricity usage, solar production, and system design.
Municipal utilities and electric cooperatives may use different rules.
Table of Contents
- What is net metering?
- What changed in Illinois?
- What does “supply-only” net metering mean?
- Why self-consumption matters
- A simple example
- What happens to solar power during the day?
- Should you oversize your solar system?
- Can a battery improve self-consumption?
- What about an electric vehicle?
- Other ways to use more solar electricity
- Ameren vs. ComEd vs. CWLP
- What about existing solar customers?
- Does the utility solar rebate affect net metering?
- Questions to ask before buying solar
- Frequently asked questions
First: What Is Net Metering?
Imagine it's a bright Illinois afternoon.
Your solar panels are generating electricity.
Your home only needs part of that electricity at that moment.
So what happens to the rest?
The excess flows through your electric meter and onto the utility grid.
Net metering is the billing mechanism that determines how you're credited for that exported electricity.
Historically, eligible Illinois residential solar customers could receive full-retail-rate net-metering treatment.
In simplified terms, qualifying exported solar electricity could offset more of the retail electricity charges associated with electricity later pulled from the grid.
But Illinois changed that structure for new solar customers.
What Changed in Illinois?
Beginning January 1, 2025, full-retail-rate net metering stopped being available to new residential and small-commercial distributed-generation customers interconnected in:
- ComEd territory
- Ameren Illinois territory
- MidAmerican territory
Older qualifying solar systems that were already receiving full-retail net metering generally retain that treatment for the life of the system, subject to certain exceptions involving major system modifications or specific rebate choices.
Newer systems operate under a different structure.
You'll often hear it described as:
Supply-only net metering.
And those three words are important.
What Does “Supply-Only” Net Metering Mean?
Your electric bill contains more than one type of charge.
Two big categories are:
Electricity supply
The actual electricity you're purchasing.
Electricity delivery
The cost associated with delivering that electricity through poles, wires, substations, meters, and the distribution system.
There can also be taxes, riders, customer charges, program charges and other line items.
Under the newer Illinois net-metering structure, qualifying exported solar electricity generally offsets the supply portion rather than providing the same full-retail treatment that older systems could receive.
Delivery charges generally continue to depend on electricity you pull from the grid.
That's where self-consumption becomes important.
Two Solar Kilowatt-Hours Can Have Different Financial Value
Imagine your solar panels generate 1 kWh at noon.
There are two possibilities.
Scenario A: Your home uses it immediately
Your air conditioner, refrigerator, appliances or EV charger consume the electricity as it's produced.
That kilowatt-hour never needs to come from the grid.
Scenario B: Your home doesn't need it
The electricity goes out to the grid.
You receive whatever net-metering treatment applies to your account.
Later that evening, your solar panels stop producing electricity.
You pull 1 kWh back from the utility.
Under supply-only net metering, the credit you received for exporting electricity may not offset all of the charges associated with purchasing electricity from the grid later.
That's why:
Producing one kilowatt-hour and using it yourself can potentially be more valuable than exporting one kilowatt-hour and buying another one later.
This doesn't mean exporting solar electricity is worthless.
Far from it.
It simply means the economics have changed.
Here's a Simple Illustrative Example
Let's deliberately keep the numbers simple.
Suppose a homeowner's hypothetical electricity costs contain:
10¢/kWh electricity supply
plus:
7¢/kWh delivery-related costs
This is only an educational example—not a current utility rate.
Now imagine the solar system generates 1 kWh.
Home uses that 1 kWh immediately
The homeowner avoids needing to purchase that kilowatt-hour from the grid.
In this simplified example, the avoided variable cost could include both the relevant supply and delivery components.
Home exports the 1 kWh
The homeowner may receive supply-related net-metering credit.
Later, when electricity is pulled from the grid, applicable delivery charges may still apply.
Again, real utility bills contain additional charges and each tariff works differently.
But this demonstrates the principle:
Where your solar electricity goes matters.
What Is Solar Self-Consumption?
Self-consumption simply means:
Using solar electricity inside your home while your panels are producing it.
Let's say your system produces:
10,000 kWh per year.
If your household directly consumes:
6,000 kWh
while exporting:
4,000 kWh
your approximate solar self-consumption rate would be:
60%.
That doesn't necessarily mean 60% is good or bad.
Every household is different.
A person working from home may naturally consume more electricity during daylight hours.
Someone who leaves at 7 a.m. and returns at 6 p.m. might export much more solar energy during the day.
That's why two houses with identical solar arrays can experience different economics.
Your Daily Energy Schedule Suddenly Matters More
Think about when your house uses electricity.
Morning
Coffee maker.
Electric water heater.
Hair dryer.
HVAC.
Breakfast appliances.
Midday
Perhaps very little if everyone is away.
Meanwhile, solar production may be approaching its strongest period.
Late afternoon
Air conditioning.
Cooking.
Laundry.
Kids coming home.
Electronics.
Evening
TV.
Lighting.
Dishwasher.
EV charging.
Most solar production is ending.
That's the mismatch.
Solar often produces heavily during hours when some households aren't consuming much electricity.
Under the old net-metering structure, that mismatch mattered less economically.
Under supply-only net metering, when you use electricity becomes more relevant.
CHECK MY HOME
Wondering how your own electricity usage lines up with solar production?
LuNova Solar can start with your home's electricity consumption and solar potential to estimate an appropriate system size and production profile.
Solar production, utility credits and potential savings vary by property, utility, rate plan and actual electricity usage.
Should You Still Aim for 100% or 110% Solar Offset?
This is where solar design becomes more interesting.
You've probably seen proposals showing:
100% offset
or:
110% offset
Offset generally compares projected annual solar generation with historical annual electricity consumption.
For example:
Annual electricity use: 12,000 kWh
Projected solar production: 13,200 kWh
Projected annual offset:
110%
But annual offset doesn't tell you when those 13,200 kWh are generated.
Your house could theoretically generate 110% of annual consumption while still purchasing significant electricity from the grid at night.
At the same time, the system may export substantial amounts of electricity during sunny afternoons.
That doesn't automatically make a 110% system wrong.
Maybe the homeowner is planning to buy an EV.
Maybe electricity consumption is expected to increase.
Maybe the project's economics still justify the larger system.
But here's the important point:
Bigger isn't automatically better.
System sizing should account for:
- Historical usage
- Expected future consumption
- Roof orientation
- Shading
- Utility rules
- Net-metering treatment
- Solar-production profile
- Household consumption patterns
- Financing
- Available incentives
- Battery plans
Simply telling every homeowner:
“We always design to 110%.”
isn't much of a design strategy.
Can a Battery Increase Solar Self-Consumption?
Potentially, yes.
A battery creates another place for excess daytime solar electricity to go.
Instead of:
Solar → Grid
you may be able to do:
Solar → Battery → Home later
For example, panels might charge a battery from noon through mid-afternoon.
Then at 7 p.m., when solar production is low or nonexistent, the battery can discharge electricity into the home.
That can increase the amount of solar-generated electricity ultimately used on-site.
But this does not automatically mean every Illinois solar project needs a battery.
A Battery Still Has to Make Financial Sense
Batteries cost money.
They have:
- Capacity limits
- Maximum power output
- Efficiency losses
- Equipment requirements
- Warranty terms
- Operating requirements
- Different backup configurations
Illinois also offers potential utility storage rebates for qualifying projects, but rebate participation comes with requirements.
For current qualifying utility storage rebates, Illinois Shines disclosures note that participating battery systems must take part in utility programs that can require batteries to discharge during scheduled windows.
So the question isn't simply:
“Can a battery increase self-consumption?”
It can.
The better question is:
“Does adding this particular battery improve the overall value of this particular project enough to justify its cost and obligations?”
Sometimes the answer may be yes.
Sometimes solar alone may make more sense.
Your Electric Vehicle Could Also Become Part of the Strategy
Suppose you own an EV.
You arrive home every night at 6 p.m.
You plug in immediately.
That might mean you're charging mostly from the grid after solar production has declined.
But what if you work from home?
Or the car sits in the driveway during the afternoon?
Charging the EV during strong solar-production hours may allow your home to directly consume more of its solar generation.
Instead of:
Solar → Grid
followed later by:
Grid → EV
you may be able to do:
Solar → EV
That's self-consumption.
And unlike buying a battery solely for energy shifting, you already purchased the EV battery for transportation.
Obviously, charging schedules still have to work with your lifestyle.
Solar should serve the homeowner—not force the homeowner to reorganize life around the panels.
Other Ways to Use More Solar Electricity During the Day
You don't necessarily need expensive technology.
Some electricity usage can potentially be shifted to solar-production hours.
For example:
Dishwasher
Run it in the afternoon rather than late at night.
Laundry
Schedule the washer and electric dryer during sunny hours when practical.
Electric water heating
Certain systems can shift some heating activity into daytime hours.
Pool equipment
Pool pumps and other controllable loads may be scheduled around solar production.
HVAC
Smart thermostats may allow some homes to pre-cool during solar-production periods rather than doing as much cooling after sunset.
EV charging
As discussed above, daytime charging can align a large electrical load with solar production.
But don't become obsessed with chasing every watt.
The goal isn't:
“Never export solar electricity.”
It's:
“Understand what your system does and design around your household intelligently.”
What About Ameren Illinois?
Start with LuNova's Ameren Illinois solar and billing guide for a utility-specific overview.
Ameren provides a useful real-world illustration of the newer billing structure.
Its current customer-owned solar billing material shows separate calculations for:
Supply Net Billable kWh
and:
Delivery Net Billable kWh.
In Ameren's example of a newer net-metering customer, exported generation can reduce supply-billed usage while delivery charges continue to reflect electricity pulled from the grid.
That's exactly why directly consuming solar electricity can matter.
If you don't pull that electricity from the grid in the first place, there's less grid-delivered usage to bill.
What About ComEd?
LuNova's ComEd solar and net-metering guide explains the main customer considerations.
ComEd customers are also subject to the statewide shift away from full-retail net metering for new residential and small-commercial systems beginning in 2025.
But homeowners shouldn't assume every line item, rate or billing calculation is identical between ComEd and Ameren.
Your:
- Utility
- Supply choice
- Rate structure
- Tariff
- Solar configuration
- Rebate participation
can all affect the final calculation.
That's why we prefer evaluating actual homeowner data rather than simply plugging “Illinois average electricity rate” into every solar proposal.
What About Springfield and CWLP?
Springfield homeowners can also review LuNova's CWLP solar guide because municipal-utility rules differ from the investor-owned utilities.
This distinction is especially important for Springfield homeowners.
City Water, Light and Power (CWLP) is a municipal utility.
The statewide ComEd/Ameren/MidAmerican net-metering change shouldn't automatically be applied to CWLP customers.
Illinois Shines specifically notes that municipal electric utilities and rural electric cooperatives may provide different approaches to crediting electricity sent to the grid.
So if you're in Springfield:
Don't use an Ameren net-metering assumption simply because Ameren serves much of central Illinois.
Your actual utility needs to be identified first.
What If I Already Had Solar Before 2025?
There's good news for many existing customers.
Qualifying systems already receiving full-retail net metering before the January 1, 2025 change generally retain that treatment for the life of the facility.
However, certain changes can affect grandfathered status.
For example, Illinois Shines currently explains that:
- A ComEd project may lose grandfathered treatment if modifications require a new interconnection application.
- An Ameren project may be affected if system nameplate capacity increases by more than 100%.
- Taking certain Distributed Generation rebates can also affect full-retail net-metering treatment.
If you're considering expanding an older solar system, don't assume you can simply add panels without affecting your existing net-metering arrangement.
Verify first.
What About the $300/kW Solar Rebate?
This is where our Tuesday article and today's article connect.
Qualifying Ameren Illinois and ComEd residential and small-commercial solar customers may have access to a $300/kW Distributed Generation rebate.
That can be financially meaningful.
But incentives and net metering need to be evaluated together.
For some existing systems, electing to take the DG rebate can change net-metering treatment.
For new systems already under the newer net-metering structure, the economics are different.
That's why comparing solar should involve more than:
System price minus incentives = savings.
You also need to understand:
How will the system interact with my utility for the next 20+ years?
Does This Mean Net Metering Is “Bad” Now?
No.
That's an oversimplification.
You can still receive value for qualifying excess solar generation sent to the grid.
The change simply means newer Illinois customers shouldn't expect the same full-retail treatment available to many older systems.
Solar can still make sense.
But design matters more.
Consumption patterns matter more.
Rate structures matter more.
And homeowners deserve to understand those differences before signing.
Questions to Ask Before Buying Solar in Illinois
Before approving a proposal, ask your solar provider:
Which net-metering rules apply to my utility?
They should know your actual utility—not merely say “Illinois.”
Am I receiving full-retail or supply-only net metering?
If you're a new Ameren, ComEd or MidAmerican customer in 2026, that distinction is especially important.
How much of my solar electricity am I expected to use directly?
Production estimates alone don't answer that.
How much electricity am I projected to export?
That helps you understand how strongly the project depends on export credits.
Why did you choose this system size?
“Because 110% is standard” isn't enough.
Would a smaller or larger system produce better economics?
Ask to compare.
What changes if I add a battery?
Compare actual projected scenarios.
Are you assuming electricity rates will increase?
If so, by how much?
Long-term projections should clearly identify assumptions.
Which utility charges remain after solar?
There may still be customer charges, delivery-related charges, riders, taxes and other costs.
Frequently Asked Questions
Does Illinois still have net metering in 2026?
Yes. Net metering still exists, but new residential and small-commercial customers interconnected in ComEd, Ameren Illinois and MidAmerican territories after December 31, 2024 generally receive supply-only rather than full-retail net-metering treatment.
What is supply-only net metering?
It generally means qualifying exported solar electricity receives credit toward electricity supply rather than the broader full-retail treatment that included eligible delivery components for older qualifying customers.
Do I still pay delivery charges with solar?
Potentially, yes. Under the newer structure, delivery-related charges generally apply to electricity pulled from the grid. Solar electricity used directly inside the home never needs to be delivered from the grid, which is one reason self-consumption matters.
Is electricity I use directly from my solar panels better than exporting it?
It can have greater economic value under the newer structure because directly consumed solar electricity can avoid the need to purchase that electricity from the grid, whereas exported electricity generally earns supply-related credit.
Should I buy a battery because net metering changed?
Not automatically. Batteries can increase self-consumption and provide other benefits, including backup power when appropriately configured, but their cost, rebates, operating requirements and expected value should be evaluated.
Should I still size solar to 100% of my annual usage?
Maybe—but annual offset shouldn't be the only design criterion. Your household's usage profile, future electricity needs, roof, utility rules, financing and export patterns should also be considered.
Does this apply to CWLP customers in Springfield?
Not automatically. CWLP is a municipal utility and may use different solar and net-metering rules. Municipal utilities and cooperatives aren't necessarily subject to the same structure as ComEd, Ameren Illinois and MidAmerican.
Are older Illinois solar systems grandfathered?
Many qualifying systems already receiving full-retail net metering before 2025 can continue receiving it for the life of the system, although major modifications or certain rebate decisions can affect eligibility.
The Bigger Lesson
Solar used to be easier to explain with one annual number:
“Your house uses 12,000 kWh and solar produces 12,000 kWh.”
Done.
But that doesn't tell the whole story anymore.
Two homes can each consume 12,000 kWh.
Two identical solar systems can each generate 12,000 kWh.
Yet the homeowners could experience different results depending on:
- When they consume electricity
- How much solar they use directly
- How much they export
- Their utility
- Their rate plan
- Whether they have battery storage
- Their future energy needs
That isn't a reason to avoid solar.
It's a reason to design solar more intelligently.
See If Solar Makes Sense for Your Home
At LuNova Solar, we believe a homeowner deserves more than a panel count and a monthly payment.
Your solar analysis should begin with:
Your home.
Your electricity usage.
Your utility.
And your future energy needs.
Then we can look at how solar production might interact with the way you actually use electricity.
SEE IF YOUR HOME QUALIFIES
Get a preliminary look at your home's solar potential and estimated energy production.
No pressure. Just better information before you make a decision.
LuNova Solar provides general educational information. Utility tariffs, incentive programs, net-metering rules and rates can change. Actual electricity costs, solar production, credits and savings vary by customer. Verify current utility and program requirements before making a financial decision.
Related Illinois Solar Guides
Sources & References
- Illinois Shines — Consumer FAQs: Current information on Illinois net metering, grandfathered systems and differences for municipal utilities and cooperatives.
- Illinois Shines — Net Metering Consumer Announcement: Explanation of the January 1, 2025 transition from full-retail to supply-only net metering for new ComEd, Ameren Illinois and MidAmerican residential and small-commercial customers.
- Ameren Illinois — Changes to Net Metering: Current billing examples showing separate supply and delivery treatment for customer-owned generation.
- Illinois Shines — 2026–27 Program Materials: Current Illinois solar program and consumer-protection information.
The central policy points above are grounded in current Illinois Shines guidance: the change took effect January 1, 2025 for new ComEd, Ameren Illinois and MidAmerican residential/small-commercial systems, while municipal utilities and co-ops can use different approaches. Ameren's current billing example also explicitly shows delivery billing based on electricity pulled from the grid while exported generation reduces supply-billed kWh.