ComEd DG Rebate for commercial and industrial storage and solar

“Competitively declared” is a supply-market term, not a program type. In ComEd territory, service to customers with demand of 100 kW and up has been declared competitive, so they buy supply from a retail supplier or on hourly pricing rather than ComEd’s fixed-price service (ComEd load forecast for the IPA). Those customers get the $250 rate; residential and under-100 kW customers get $300 (Illinois Power Agency).

Because the window is fixed, “number of events” and “event duration” are known: about 88 weekdays and 176 hours in summer 2027. What can change is the commitment level. The tariff says “there is no minimum commitment required,” and a participant chooses its committed injections in the agreement (Rider SDVPP). How ComEd will tie that commitment to the rebated kWh is one of the details still to come.

Two bill charges are worth far more than the VPP payment. ComEd bills the Distribution Facilities Charge on the highest demand in each month, $12.84 per kW for Large Load customers at secondary voltage in 2026 (General Energy, ComEd Rate BESH). PJM capacity costs are assigned by each customer’s PLC, its load during PJM’s summer peak hours. Capacity cleared at the $333.44 per MW-day cap for 2027/28 and $325 for 2028/29, about $119–$122 per kW-year (PJM, PJM).

The 4–6 p.m. window often overlaps the late-afternoon hours when PJM and ComEd peaks occur, so one discharge can serve the VPP, the capacity charge and often the monthly demand peak. A site whose own peak falls in the morning, or whose supply contract has a fixed all-in price, captures much less.

Peak savings recur on the bill; they are avoided costs, not payments. The Distribution Facilities Charge is billed on the highest demand in each month, so a battery that holds the monthly peak down lowers that line every month it succeeds. One missed afternoon resets the month, which is why the central case counts only 150 of 250 kW as reliable (ComEd Rate BESH).

Capacity savings arrive a year later. The PLC is set from load in the prior summer’s peak hours and priced from June to May (PJM). For competitively declared customers, the saving reaches the bill only if the retail supply contract passes capacity through rather than bundling it in a fixed price. PJM does not pay the customer; the customer simply buys less capacity.

Payments are the smaller layers. The rebate and federal credit arrive once. The scheduled dispatch VPP pays $10 per kW-season (Rider SDVPP). A separate PJM demand response payment through a curtailment service provider is possible in principle, but ComEd may reduce VPP credit for hours paid by another grid-services program.

The demand charge and capacity layers are what carry storage past 100%; the VPP layer is a sliver. The flat-load, fixed-price case shows the reverse: one-time incentives alone cover about two-thirds of cost, and the bill has little left to give.

Feasible. In the central case the rebate ($250,000) and credit ($105,000) cut the net cost to about $245,000. Annual value is about $51,200: $23,100 in demand charges, $24,300 in capacity, $2,500 from the VPP and $5,000 from energy shifting, less O&M. A 2-hour battery pays back faster (3.2 years) because the dispatch window and the capacity peak are short, so the extra energy of a 4-hour battery earns little. The rebate scales with kWh, but so does the cost.

Marginal. Without the federal credit, payback stretches to about 6.8 years. Storage projects starting construction in 2026 must meet foreign-sourcing (FEOC) limits to claim the credit (Sidley). A 6-hour battery loses part of the rebate to the 5 kWh-per-kW cap. Capacity at the auction floor with weaker peak shaving lands near 7.6 years.

Unfeasible. A small business on ComEd’s fixed-price supply has no capacity charge to avoid, so payback is about 13 years even at $300 per kWh. A flat 24-hour load on a fixed-price supply contract barely moves its monthly peak; the VPP and a little demand shaving leave payback near 73 years.

Capturing PJM peak hours and the federal credit matter most. Missing the peaks entirely, or holding a supply contract that does not pass capacity savings through, nearly doubles the payback. Even a fivefold increase in the VPP rate would change payback by less than a year.

The site’s line above is only half of the deal. The developer pays the full $600k, carries maintenance, insurance and performance risk, and prices all of it into the contract to earn a return on its capital (Morgan Lewis). Third-party storage contracts usually run 15 years or more (Peak Power), and lenders treat 15- to 20-year terms as financeable (Illinois Power Agency). The chart below values each deal from the developer’s side.

The rebate makes ComEd workable for a third-party owner, but not at a 30% split on a short contract. PJM capacity is the closest thing here to an ongoing capacity sale: cutting the site’s peak load contribution avoids about $24k a year at the capped auction price, on top of about $23k in demand charges. At 8%, a developer can leave the site about 20% of those savings over 15 years, or about 29% over 20. The VPP pay is small and lasts five summers. After the PJM price collar ends with the 2029/30 auction, capacity value could move sharply in either direction.

Compare: Ameren Illinois runs the same statutory program at the same $10 rate in MISO (Ameren Illinois deep dive). Con Edison’s C&I programs pay $18–$25 per kW-month for event-based relief (Con Edison C&I deep dive).