Full retail net metering, for systems 25 kW and under
CWLP currently offers full retail net metering and interconnection for systems of 25 kW or smaller, through an application process. Full retail means an exported kilowatt-hour is credited at the same rate you pay for one you draw, rather than at a narrower supply-only rate.
That is worth stating plainly because it is not the Illinois norm any more. New residential net metering customers in ComEd and Ameren Illinois territory moved to supply-only crediting, where the credit covers the electricity supply portion of the bill rather than the full retail rate. Springfield sits outside that because CWLP is municipally owned and sets its own terms.
The word to hold onto is currently. A municipal utility's program is set locally and can be revised without the commission proceedings that accompany an investor-owned utility's tariff change, so confirm the terms with CWLP directly at the point you are quoted rather than relying on this or any other page. The 25 kW ceiling is comfortably above a normal residential system, so for a house the limit is unlikely to bind.
The March expiry, and what it means for sizing
When a billing period's production exceeds usage, you are billed zero kWh for that period and the surplus is banked. The bank is not permanent: it expires each March billing cycle.
Line that up with the seasons and the design implication is clear. Solar output peaks in summer and falls through the winter, so a system that runs a surplus from spring onwards accumulates a bank that carries into the darker months, which is exactly what you want. But anything still sitting in the bank when the March cycle arrives is gone, and it was electricity you generated and never got paid for.
So the sensible target is a system whose annual production roughly matches your annual consumption, sized so that the bank is being drawn down over winter rather than growing past March. An array built well beyond your usage does not bank value indefinitely, it donates the excess once a year. Ask your installer to model production against your twelve-month usage on a monthly basis, and to show what the bank looks like heading into March.
Applying, and what to ask CWLP
Net metering and interconnection at CWLP run through an application process, which is a separate step from any construction approval and has its own timing. When you check on a project's progress, ask which approval is outstanding rather than accepting a single completion date, because a system can be installed and still waiting to be connected.
Ask CWLP to confirm the current net metering terms, the system size limit, what the application requires and how long it takes. Ask your installer to show you the application before it is submitted, since it defines the system that gets approved and a change afterwards means going back.
It is also worth asking whether anything about the arrangement is under review. Because the program is the city's own, the place to learn about a change is the utility rather than a national solar website, which will not track a municipal program.
If a rooftop system is not the answer
CWLP also runs mySolar, a community solar subscription, and Renewable Choice, a program for purchasing renewable energy credits. Neither is an owned system and neither produces a payback in the way an array on your own roof does, but both exist for people whose housing or finances rule the roof out.
That covers a real share of the city. Buildings of 20 or more units hold 7.1 percent of Springfield's 57,424 housing units, and in those the roof belongs to the building owner rather than the resident. Mobile homes are 3.4 percent, a larger share than in most cities in this dataset, and there the structure, the ground and any park rules come before the electrical design.
If you are in either group, ask CWLP what mySolar costs and how it appears on your bill. Judge it as a subscription decision, since that is what it is, rather than comparing it against a payback figure for a system you cannot install.
Output, roofs and what a 2026 project costs
Plan on roughly 1,318 kWh a year for every kW installed. The figure is derived from satellite irradiance data with a standard performance ratio applied rather than measured on local systems, so it is a screening number. Orientation, pitch, shade and the usable area left once vents, stacks and setbacks come out decide what a particular roof does.
Single-detached houses are 64.9 percent of the housing stock here and single-attached units another 8.1 percent, so most residents control their own roof. Ask for production modelled per roof plane rather than as one house total, with the shading assumptions stated.
On cost, the 30 percent federal residential tax credit under Section 25D applied through December 31, 2025 and is not available for a purchased home system placed in service after that date, so a 2026 purchase here cannot claim it. Illinois Shines works through Approved Vendors who receive Renewable Energy Credit payments and may pass the value through as reduced project cost, so ask any vendor for their Disclosure Form and, because Springfield is served by a municipal utility rather than an investor-owned one, ask them to confirm your address qualifies before you count on it.