Business electricity and natural gas suppliers in Connecticut
How commercial and industrial companies in Connecticut buy electricity and gas: which utilities deliver it, what happens if you do not choose a supplier, how ISO-NE sets the costs behind the price, and how to run a competitive purchase.
Connecticut customers of Eversource and United Illuminating can buy generation from a licensed electric supplier. Customers who do not choose are placed on the utility's default service, which is split by size: Standard Service for smaller customers and Last Resort Service for large ones. Discovery Energy Utility Audits buys electricity and natural gas for multi-site companies with sites in Connecticut: it inventories every account, invites every active supplier to one RFP, compares offers line for line, tracks each contract to renewal in TaraBase and audits the utility bills behind it. Its procurement fee is disclosed in advance.
01 / 07
Who delivers electricity in Connecticut
The utility in each territory owns the wires and bills delivery under a tariff the Public Utilities Regulatory Authority (PURA) approves, whoever supplies the energy. Municipal utilities and cooperatives usually sit outside retail choice. Every utility in the state is listed in Discovery's Connecticut electric utility directory.
| Utility | Area | Grid |
|---|---|---|
| Eversource (Connecticut Light and Power) | Most of Connecticut | ISO-NE |
| United Illuminating (UI) | New Haven, Bridgeport and southern Connecticut | ISO-NE |
02 / 07
What happens if a business does not choose a supplier
Under Eversource's tariff, Standard Service is for customers without a demand meter or with maximum demand under 500 kW, with prices that change no more often than quarterly; Last Resort Service is for demand-metered customers above 500 kW, with prices that change monthly and less protection from market swings. UI applies the same 500 kW line. A customer returning to Last Resort Service after leaving a supplier faces a one-year switching moratorium, unless the return was caused by a supplier default. Both utilities buy default supply through PURA-reviewed RFPs and earn no profit on it.
03 / 07
Capacity, transmission and why prices moved
Connecticut is in ISO New England, where capacity is bought through the Forward Capacity Market and transmission is charged through regional network service. New England's wholesale prices follow natural gas closely and spike in cold snaps when pipeline capacity into the region is tight, which is why winter pricing matters as much as summer in Connecticut contracts. Connecticut commercial prices fell 5.4% over the 12 months to July 2026 but remain among the highest in the country, at 22.14 cents per kWh.
How a contract treats these charges, fixed or passed through, matters more than the headline rate. See charges by market.
04 / 07
Natural gas for businesses in Connecticut
Eversource Gas (Yankee Gas), Southern Connecticut Gas and Connecticut Natural Gas deliver gas; larger commercial and industrial customers can buy gas from a supplier under transportation service. New England's pipeline constraints make basis and winter risk central to any gas contract; see Discovery's outlook for Boston for the regional picture.
Discovery's natural gas procurement page explains transport eligibility, NYMEX and basis, balancing, and firm versus interruptible service.
05 / 07
Brokers, suppliers and licensing in Connecticut
Connecticut requires electric suppliers to be licensed and electric aggregators and agents to register with PURA. Ask any broker for its registration. Discovery Energy acts as an energy broker in its procurement work; its energy broker licenses and registrations are held by Energy Auction Exchange, LLC. Ask Discovery for the license or registration that covers your Connecticut sites. Suppliers serving Connecticut customers are licensed by the Public Utilities Regulatory Authority (PURA), which keeps the list of active suppliers. A broker can only bid your Connecticut sites to suppliers active in each utility territory, and only if it is licensed or registered where the state requires it. How brokers are paid, and what to ask, is covered in energy broker fees.
06 / 07
How Discovery buys electricity and gas in Connecticut
Inventory
Every Connecticut account: utility, rate class, default or supplier service, contract end date, usage and 4CP or peak data.
Check the bills
Rate class, riders, demand and meter setup are tested against the tariff before a contract locks in the baseline. See utility bill audits.
Time and bid
One RFP to every active supplier, timed with the monthly Energy Risk Report, with Connecticut sites bid alongside the rest of the portfolio. See the multi-state RFP.
Compare and sign
Offers side by side on the same terms, in each structure that fits: fixed, fixed with pass-throughs, index, block and index or layered. No contract is signed without your written approval.
Track
Every contract in TaraBase, with renewals flagged well in advance so nothing rolls onto default or month-to-month pricing.
How far back utility overcharges can be refunded in Connecticut is on the Connecticut refunds page.
07 / 07
Questions about buying energy in Connecticut
Can businesses choose their electricity supplier in Connecticut?
Connecticut customers of Eversource and United Illuminating can buy generation from a licensed electric supplier. Customers who do not choose are placed on the utility's default service, which is split by size: Standard Service for smaller customers and Last Resort Service for large ones.
Who are the retail energy providers in Connecticut?
Suppliers are licensed by the Public Utilities Regulatory Authority (PURA), which keeps the list of active suppliers. Discovery invites every supplier active in each utility territory to its RFPs rather than a short list.
Which electric companies serve businesses in Connecticut?
Eversource (Connecticut Light and Power); United Illuminating (UI). They deliver the power; the supply can come from a competitive supplier.
How do I compare commercial electricity offers in Connecticut?
Put every offer on the same product, term and treatment of capacity, transmission and other pass-through charges, then compare price. Check usage tolerance, auto-renewal and early termination terms before signing.
Sources
- Eversource, Connecticut tariff, Standard Service and Last Resort Service, 500 kW line and switching moratorium.
- United Illuminating, Rate LPT Last Resort Service, large customers with peak demand of 500 kW or more.
- Connecticut Office of Consumer Counsel, electricity FAQ, utilities earn no profit on supply.
- EIA data compiled by StartBusinessByState, Connecticut commercial prices down 5.4% to 22.14 cents per kWh in the 12 months to July 2026.
Find out what your bills should have cost.
Send one recent bill per site, or a list of accounts. We tell you where we expect findings before you sign anything. No upfront audit fee.