Pursuant to Title 35-A § 3218(4), by March 1, 2026 and annually thereafter, each large, investor-owned transmission and distribution utility must provide to the Commission’s interconnection ombudsman with the average interconnection costs for the previous calendar year by project size. Further, by May 1, 2026, and annually thereafter, the interconnection ombudsman shall publish this data along with disclaimer language regarding the range and factors associated with the cost of interconnection on the Commission's publicly accessible website. These tables provide the average interconnection costs for last calendar year.
Due to the limitless number of project sizes, the average interconnection costs included in the tables are broken down by project levels as defined in Chapter 324 of the Commission’s rules. Below is a summary of each project level. Specific definitions are included in Chapter 324 §2.
- Level 1: Inverter-based generating facilities with a nameplate rating of up to 25kW.
- Level 2: Generating facilities with a nameplate rating of up to 2MW.
- On-Site-Load ICGF: Level 2 generating facilities between 25 kW and 250 kW that only serve to offset on-site load.
- Level 3: Generating facilities with a nameplate rating of up to 10MW that do not export power to the grid.
- Level 4: All other generating facilities not subject to FERC jurisdiction.
Disclaimers:
- Tables include the average interconnection costs for generating facilities subject to the standard written disclosure under § 3218(2), which includes “solar energy equipment”, as defined under § 3218(1), installed on the customer’s side of the utility meter.
- Tables reflect the average of actual interconnection costs assessed to generating facilities in the prior calendar year, and do not include cost estimates.
- Not all categories of interconnection costs are applicable to each project level. These instances are noted in the tables as "N/A."
- Not all categories of interconnection costs are assessed each year to each project level. These instances are noted in the tables as "—.”
- Interconnection costs may be assessed to a generating facility across multiple years. The average interconnection costs in the tables reflect only the interconnection costs assessed to generating facilities in the prior calendar year.
- The cost of network upgrades may vary significantly depending on multiple factors including (but not limited to): generating facility size, project level, whether the generating facility qualifies for cost sharing, the circuit to which it interconnects, the generating facility’s point of interconnection location on the circuit, the amount of aggregated generation allocated to the circuit, the circuit’s limiting elements, and the circuit’s load and voltage profiles.
- The sample size of generating facilities used to calculate average interconnection costs may vary significantly across project levels.
- The range associated with average interconnection costs can vary significantly depending on project level and interconnection cost category.
- All data included in these tables were calculated by the utilities and submitted to the interconnection ombudsman.
- Data may include outliers that impact the average interconnection cost.
- Historical averages may not be indicative of future interconnection costs.
Central Maine Power - 2025
| Interconnection Costs | Level 1 ≤ 25kW |
On-Site-Load ICGFs >25kW and ≤ 250kW |
Level 2 ≤ 2MW |
Level 3 Non-Exporting, ≤ 10 MW |
Level 4 All Other non-FERC |
|---|---|---|---|---|---|
| Application Fee (1) | $100 | $190 | $390 | $4,435 | - |
| Cost Sharing Fee (2) | $150 | $1,065 | N/A | N/A | N/A |
| Ombudsman Fee (3) | $40 | $40 | $40 | $40 | - |
| Additional Review (4) | - | $1,779 | $1,736 | - | N/A |
| Distribution Studies | N/A | N/A | N/A | N/A | - |
| Transmission Studies | N/A | N/A | - | - | - |
| Network Upgrades (5) | - | - | $1,233 | - | - |
Versant - 2025
| Interconnection Costs | Level 1 ≤ 25kW |
On-Site-Load ICGFs >25kW and ≤ 250kW |
Level 2 ≤ 2MW |
Level 3 Non-Exporting, ≤ 10 MW |
Level 4 All Other non-FERC |
|---|---|---|---|---|---|
| Application Fee (1) | $100 | $206 | $749 | $128 | - |
| Cost Sharing Fee (2) | $150 | $1,722 | N/A | N/A | N/A |
| Ombudsman Fee (3) | $40 | $40 | - | $40 | - |
| Additional Review (4) | $500 | $1,000 | - | - | N/A |
| Distribution Studies | N/A | N/A | N/A | N/A | - |
| Transmission Studies | N/A | N/A | - | - | - |
| Network Upgrades (5) | $214 | $9,750 | $22,801 | $8,050 | - |
- Application Fee for each project level are established in Chapter 324 of the Commission's rules. See ch. 324 § 11(L), § 12(K), § 13(K), and § 14(X).
- Cost Sharing Fee for Level 1s and On-Site-Load ICGFs are established in Chapter 324 of the Commission's rules. See ch. 324 § 3(B)(1) and § 3(B)(2).
- Ombudsman Fee is established in Chapter 328 of the Commission's rules. See ch. 328 § 2(B)(5).
- Indicates average cost of Additional Review for projects required to undergo Additional Review.
- Indicates the average combined cost of distribution upgrades, interconnection facilities, and transmission upgrades for projects that received their final reconciliation invoice in 2025. For Level 1s and On-Site-Load ICGFs, this indicates the average cost in excess of what's covered under cost sharing. See ch. 324 § 3(B)(1) and § 3(B)(2).