City Water, Light and Power Springfield solar interconnection: tiers, fees and insurance

Q: How does City Water, Light and Power Springfield solar interconnection measure system size?

The published limits do not say whether they are measured in alternating or direct current.

How the size is measured: not published

The published limits here are stated in kilowatts without saying whether that is the inverter rating in alternating current or the array rating in direct current. On a system near a threshold that decides which band it lands in, so the checker asks the question rather than choosing an answer.

Size bands and what each one obliges

Under 25, on the standard packet Size 0 to 25 kW	A $400 check is due with the packet, itemized as a $50 application fee, $150 net meter, $50 interconnection testing and $150 installation of two meters. The check is held until the meters are installed. No insurance is required. $400 check with the application packet Customer furnishes both meter sockets from the approved list, a NEMA 3R fused disconnect, tap connectors, conduit and all wiring Lockable exterior fused disconnect
Over 25, engineering review and line side connection Size 25.001 to 2500 kW	An additional $300 engineering review fee is due with the packet, and the solar circuit must be connected to the line side of the revenue meter, which is a materially more expensive service rework than a load side backfeed breaker. The transmission and distribution engineering department reviews and approves the installation. $300 engineering review fee with the packet Line side connection to the revenue meter Transmission and distribution engineering approval

Under 25, on the standard packet Size 0 to 25 kW

A $400 check is due with the packet, itemized as a $50 application fee, $150 net meter, $50 interconnection testing and $150 installation of two meters. The check is held until the meters are installed. No insurance is required.

$400 check with the application packet
Customer furnishes both meter sockets from the approved list, a NEMA 3R fused disconnect, tap connectors, conduit and all wiring
Lockable exterior fused disconnect

Over 25, engineering review and line side connection Size 25.001 to 2500 kW

An additional $300 engineering review fee is due with the packet, and the solar circuit must be connected to the line side of the revenue meter, which is a materially more expensive service rework than a load side backfeed breaker. The transmission and distribution engineering department reviews and approves the installation.

$300 engineering review fee with the packet
Line side connection to the revenue meter
Transmission and distribution engineering approval

The screens that decide it

The single 25 threshold is stated five different ways Limit 25 kW.
The information sheet says 25 kW, the agreement says 25 kVA, the agreement’s own form field says kW or kVA, the solar data sheet collects only the total array size and has no inverter field, and the approved wiring diagrams say 25 kW AC. The AC reading is used here because the wiring diagrams are the most specific and the only place the utility writes AC. Any design between roughly 20 and 30 on either reading should be confirmed in writing before the sale.
Below the 250 kVA point where annual protective testing begins Limit 250 kW.
Interconnection related protective functions and associated energy storage devices must be tested at least every three years below 250 kVA and yearly at 250 kVA and above, with logs available to the engineering department. That is a recurring operating cost, not a one time one.

Ask the utility this, before you sell it

Is the 25 threshold measured on inverter AC, on the DC array, or in kVA? The packet says all three and the data sheet the utility reads collects only the DC array size.
How long will review take? No approval timeline is published; the only published duration is two weeks to install the two meters after the check is processed.
Does this site have three phase service? A three phase service requires a three phase generator.
If the solar circuit lands inside the billing meter base, coordination with the maintenance supervisor is required at least one week ahead. Is that needed here?

Worth knowing before you quote

Net metering is open and is full retail while it lasts, but the credit is confiscated rather than paid: on the 1 March billing cycle reconciliation, or on closing the account, the customer surrenders any excess energy, and under no circumstances are there payments or credit transfers. The contract also says outright that there is no guarantee of net metering in perpetuity. No insurance is required and liability is handled by a hold harmless clause alone. No aggregate program cap, no percentage of consumption cap, no fifteen percent screen and no minimum load test are published. The isolation device may be locked off by the utility during maintenance and may not be returned to the on position other than by an authorized city official. The contractor runs the whole process; the customer signs the interconnection agreement and the net meter contract.

Source

City Water, Light and Power Springfield Illinois Solar Application Packet revised 12 June 2023, containing the Solar Project Information Sheet, the Application for Interconnection, the Solar Data Sheet and the approved wiring diagrams, with the Net Metering Contract revised 12 June 2023

Read and recorded 2026-09-12. Municipal or public power utility, outside its state's interconnection rule. Its own published documents govern. An Illinois municipal utility. The Illinois Commerce Commission smart solar billing transition binds investor owned utilities and does not reach City Water, Light and Power, whose own documents still provide full retail netting.

All Illinois interconnection rules

Size bands and what each one obliges

The screens that decide it

Ask the utility this, before you sell it

Worth knowing before you quote

What to do with this