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Get a Free QuoteConnecticut has the best TOU spread in New England. Eversource Rate 7 offers a $0.23/kWh peak-to-off-peak spread, and the ESS program pays $30-$130/kWh at enrollment plus $300-$550/kW every year for ten years of Active Dispatch. With the federal ITC dead for homeowners, these programs are how CT batteries actually pay for themselves.
$0.23
Best TOU Spread (Eversource)
$30-$130
ESS Enrollment /kWh
$300-$550
ESS /kW/yr, all 10 yrs
$0 ITC
25D Expired
A 13.5 kWh battery (Tesla Powerwall 3) in Eversource CT territory, assuming ~11.5 kW average measured contribution during Active Dispatch events, can generate $4,714/year in combined value from TOU arbitrage, the ESS Active Dispatch performance incentive, self-consumption savings, and RRES adjustment offsets. With the ESS Enrollment Incentive of $405, the 10-year total value reaches $47,545. In UI territory, the same battery generates $4,754/year with a 10-year total of $47,945. Connecticut has the best TOU arbitrage opportunity in New England.
Eversource Annual
$4,714
UI Annual
$4,754
ESS Enrollment
$405
10-Year (Eversource)
$47,545
The federal residential solar tax credit (Section 25D) expired December 31, 2025. Connecticut homeowners now pay full price for batteries with no federal tax break. But CT has something most states do not: the ESS program and aggressive TOU spreads.
While homeowners get $0 in federal tax credits, third-party financing companies can still claim the Section 48E commercial ITC (30%). For the solar portion the begin-construction safe harbor closed July 4, 2026, and new starts still qualify if placed in service by December 31, 2027. Energy storage technology is not subject to the December 31, 2027 placed-in-service deadline or the July 4, 2026 begin-construction trigger — both apply to applicable wind and solar facilities only, and Section 48E(e)(4)(C) expressly excepts energy storage technology (IRS Notice 2025-42, section 2.02). A standalone commercial battery remains eligible for the statutory 6% Section 48E credit, increased to 30% when the applicable wage and apprenticeship requirements are met, under the standard clean-electricity phase-out that starts at the later of 2032 or when U.S. greenhouse gas emissions from electricity are 25% of 2022 emissions or lower. The third-party system owner (financing company) claims the ITC — not the homeowner or installer. This makes PPA and lease agreements more attractive because the financing company passes their ITC savings to you as a lower electricity rate.
Eversource CT serves approximately 70% of Connecticut residential customers across Hartford, central, north, and eastern CT. Their Rate 7 (Time-of-Day) tariff has the widest peak-to-off-peak spread in all of New England — making it the single best utility territory for battery arbitrage north of New York.
Eversource Connecticut — Hartford, central, north, and east CT
Peak
Mon-Fri, 12:00 PM – 8:00 PM
$0.307/kWh
Off-Peak
Mon-Fri 8 PM–12 PM, All day Sat & Sun
$0.272/kWh
Flat Rate
Standard service
$0.281/kWh
Peak-to-Off-Peak Spread
$0.035
per kWh
* Rates are all-in (supply + delivery). Jan-Jun 2026 filing. TOU requires 1-year commitment. Eversource installs TOU meter at no cost.
United Illuminating (UI) serves approximately 30% of Connecticut customers in New Haven, Bridgeport, and southwest CT. Their Rate RT (Time-of-Day) offers a narrower but still valuable TOU spread. UI territory includes several economically distressed municipalities that qualify for enhanced ESS incentives.
United Illuminating — New Haven, Bridgeport, southwest CT
Peak
Mon-Fri, 12:00 PM – 8:00 PM
$0.318/kWh
Off-Peak
Mon-Fri 8 PM–12 PM, All day Sat & Sun
$0.283/kWh
Flat Rate
Standard service
$0.292/kWh
Peak-to-Off-Peak Spread
$0.035
per kWh
UI Underserved Community Bonus
New Haven and Bridgeport qualify for the ESS underserved performance tier ($450/kW/year vs the standard $300/kW/year) — 50% more every year of the 10-year term.
Connecticut replaced ConnectedSolutions (closed December 1, 2023) with the Energy Storage Solutions (ESS) program — and it is significantly more generous. Since PURA restructured it effective April 1, 2026, ESS combines a one-time Enrollment Incentive with much larger Active Dispatch performance payments over ten years, creating the strongest battery value proposition in New England.
Administered by EnergizeCT / CT Green Bank. Solar pairing is NOT required — standalone batteries qualify.
| Circuit Location | $/kWh | 13.5 kWh Battery | Basis |
|---|---|---|---|
| Non-Grid Edge | $30 | $405 | Standard distribution circuit |
| Grid Edge | $130 | $1,755 | Top 10% of circuits by outage count or outage duration since July 1, 2012 |
| Tier | $/kW/yr | At ~11.5 kW measured | 10-Year Total | Basis |
|---|---|---|---|---|
| Standard | $300 | $3,450/yr | $34,500 | All CT homeowners |
| Underserved Community | $450 | $5,175/yr | $51,750 | Economically distressed municipalities |
| Low-Income | $550 | $6,325/yr | $63,250 | Income-qualified households |
12:00 PM – 9:00 PM (June 1 – September 30), events 1–3 hours
30–60 events per season
12:00 PM – 9:00 PM (November 1 – March 31), events 1–3 hours
1–10 events per season
Discharge requirement: No fixed discharge depth — reserve capacity is the OEM minimum recommendation, and payment follows measured average contribution across the season. The fixed 80%-discharge obligation belonged to the retired Passive Dispatch track and does not apply to new enrollments. Note that whatever you hold back for backup also lowers the capacity you commit at enrollment, and the performance incentive is paid on committed capacity.
The real power of a CT battery is stacking multiple revenue streams. No single stream justifies the cost — but combined, they create one of the strongest battery value propositions in the country.
ESS Enrollment
$405
10-Year Total
$47,545
ESS Enrollment
$405
10-Year Total
$47,945
The 8-hour peak window (12 PM - 8 PM) in CT means your battery needs enough capacity to discharge throughout the entire peak period. Here is how different battery sizes perform in each utility territory.
| Battery Size | Example | Eversource Annual | UI Annual | ESS Enrollment | 5-Year Total (Ev.) |
|---|---|---|---|---|---|
| 5 kW / 5 kWh | Enphase IQ 5P | $2,043/yr | $2,060/yr | $150 | $10,365 |
| 10 kW / 10 kWh | Enphase IQ 10T | $4,086/yr | $4,121/yr | $300 | $20,730 |
| 11.5 kW / 13.5 kWh | Tesla Powerwall 3 | $4,714/yr | $4,754/yr | $405 | $23,975 |
Values include TOU arbitrage, the ESS Active Dispatch performance incentive, self-consumption savings, and RRES adjustment offset. The enrollment incentive assumes a non-Grid Edge circuit ($30/kWh) and the performance incentive the standard tier ($300/kW/yr) on ~11.5 kW of average measured contribution during events — actual payments depend on measured performance. Grid Edge homes, underserved communities and income-qualified households earn more. Source: PURA Docket No. 25-08-05 decision (December 17, 2025); CT Energy Storage Solutions Program Manual revised February 11, 2026. Verified August 3, 2026.
These batteries are approved for the CT ESS program. All support Active Dispatch. Every enrolled battery needs at least a 10-year manufacturer warranty plus a minimum 10-year workmanship warranty from your installer.
Most popular, integrated inverter
ESS enrollment: $405 ($1,755 Grid Edge)
AC-coupled, legacy model
ESS enrollment: $405 ($1,755 Grid Edge)
Modular, pairs with Enphase microinverters
ESS enrollment: $150 ($650 Grid Edge)
Larger Enphase option
ESS enrollment: $302 ($1,310 Grid Edge)
DC-coupled, SolarEdge ecosystem
ESS enrollment: $291 ($1,261 Grid Edge)
Whole-home backup capable
ESS enrollment: $408 ($1,768 Grid Edge)
Scalable 3–18 kWh
ESS enrollment: $270 ($1,170 Grid Edge)
Premium smart home integration
ESS enrollment: $360 ($1,560 Grid Edge)
Month-by-month TOU arbitrage estimates for a 13.5 kWh battery at 85% round-trip efficiency. Both utilities use the same peak window (12 PM - 8 PM weekdays), so the difference is purely in rate spread.
| Month | Weekdays | Eversource Arb. | UI Arb. | Note |
|---|---|---|---|---|
| January | 22 | $89 | $72 | Winter off-peak |
| February | 20 | $81 | $65 | Shortest month |
| March | 21 | $85 | $69 | Transition |
| April | 22 | $89 | $72 | Spring rates |
| May | 22 | $89 | $72 | Pre-summer |
| June | 22 | $89 | $72 | Summer begins |
| July | 22 | $89 | $72 | Peak summer |
| August | 22 | $89 | $72 | Peak summer |
| September | 21 | $85 | $69 | Late summer |
| October | 23 | $93 | $75 | Fall rates |
| November | 21 | $85 | $69 | Winter prep |
| December | 22 | $89 | $72 | Winter off-peak |
| Annual Total | 260 | $1,052 | $851 | TOU arb. only |
Arbitrage = usable kWh x spread x weekdays x 85% RTE. Does not include ESS DR payments, self-consumption, or RRES offset — those are additional. Summer rates may differ from winter filings.
Side-by-side comparison of the two CT utilities for solar + battery strategy.
| Feature | Eversource CT | United Illuminating |
|---|---|---|
| Territory | Hartford, central, north, and east CT | New Haven, Bridgeport, southwest CT |
| Coverage | ~70% of CT | ~30% of CT |
| TOU Rate | Rate 7 (Time-of-Day) | Rate RT (Time-of-Day) |
| Peak Rate (all-in) | $0.307/kWh | $0.318/kWh |
| Off-Peak Rate (all-in) | $0.272/kWh | $0.283/kWh |
| TOU Spread | $0.035/kWh | $0.035/kWh |
| Flat Rate | $0.281/kWh | $0.292/kWh |
| Peak Hours | Mon-Fri, 12:00 PM – 8:00 PM | Mon-Fri, 12:00 PM – 8:00 PM |
| Annual TOU Arb. (13.5 kWh) | ~$1,052 | ~$851 |
| Interconnection | 4-8 weeks | 4-8 weeks |
| RRES Program | Yes (administrator) | Yes (administrator) |
| Battery Verdict | Best in NE | Strong |
CT Green Bank's Smart-E Loan offers some of the lowest interest rates available for clean energy financing. Battery storage is a qualifying Smart-E measure at the standard Smart-E rate — 6.99% APR on 5-10 year terms, 7.49% at 12 years, 7.99% at 15 years — up to $50,000. The discounted 1.99% APR rate is a heat-pump-only special and does not extend to batteries.
Battery may be cash-flow positive from day one depending on utility territory and ESS tier. Smart-E rates for both solar and battery installations are 6.99-7.99% — the discounted 1.99% rate is a heat-pump-only special and does not apply to either.
Both Eversource and UI follow the same general interconnection timeline for battery storage systems in Connecticut.
File interconnection application with your utility (Eversource or UI). Include battery specs, inverter data, and site plan. Your installer handles this.
Utility reviews application for grid compatibility. May request additional documentation for larger systems or Grid Edge locations.
Apply for ESS incentives through EnergizeCT. Can be done simultaneously with utility interconnection. Pre-approval typically takes 1-2 weeks.
Battery installation by licensed CT electrician. Municipal electrical inspection required. Schedule varies by town.
Utility issues PTO after passing inspection. Your battery is now grid-connected and can begin TOU arbitrage and ESS dispatch.
Request Rate 7 (Eversource) or Rate RT (UI). Eversource installs TOU meter at no cost. One-year minimum commitment.
Total timeline: 4-8 weeks from application to PTO. Faster in towns with established solar/battery permitting processes. Grid Edge locations may receive priority processing.
Common questions about time-of-use rates, ESS incentives, and battery strategy in Connecticut.
Get a custom battery + TOU analysis for your Connecticut home. We will calculate your exact ESS incentive, TOU arbitrage potential, and total revenue stack based on your utility territory and usage.
Smart-E standard rate: 6.99-7.99% APR, no announced end date. Section 48E TPO, solar portion: safe harbor closed July 4, 2026, new starts in service by December 31, 2027. Energy storage is excepted from both dates.