Commercial · Flat roof · 2026
35 kW on a restoration company's flat roof, and the incentives covered 87% of it.
The system
| Size | 35.4 kW DC, 25 kW AC, 60 modules |
| Mounting | Ballasted flat roof, no penetrations |
| Inverters | Two Fronius Primo GEN24 10 kW, one 5 kW |
| First-year production | 43,357 kWh |
| Site | Commercial flat roof, minimal shading |
A note on how we present this.
Some companies add the depreciation deduction to the credits and call the total an incentive. On this project that would read as $179,054 and 136% of cost. It isn't. A deduction is not cash, and at 21% that write-off is worth $23,617 rather than $111,933. We show the cash value. 87% is the real number and it is still exceptional.
The money
| Project cost | $132,216 |
| Federal credit, Section 48E at 30% | $39,506 |
| Illinois Shines, net of fees | $41,272 |
| Utility distributed generation rebate | $10,620 |
| First-year depreciation, cash value at 21% | $23,617 |
| Total benefit | $115,015 |
| Estimated annual electricity saving | $8,238 |
The headline, with its condition attached: the incentives cover about 87% of the project cost, leaving roughly $17,200 net against an $8,238 annual saving, so the payback lands near two years.
That depends entirely on the business having federal tax liability to absorb both the credit and the first-year deduction. A business without it sees a smaller, slower benefit. We model depreciation at a 21% federal corporate rate with 100% bonus depreciation and the required 50% ITC basis reduction, and we send the working to the accountant before anyone signs.
The deadline that applies to anyone reading this: Section 48E requires the system placed in service by 31 December 2027. Commercial solar
Warranty: 25 years on the modules, 25 on the installation, 12 on the inverter, and a 25-year leak-free guarantee on every roof penetration.
Send us twelve months of bills.
We'll tell you within a week whether your property is in the same position, and we will send your accountant the working before anyone signs.
Tell us what you need
We'll tell you within a week whether the property is worth a proposal. If it isn't, we'll say so and tell you why.