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Commercial Solar EPC in Vermont

Ferrius Energy is a commercial solar and battery storage EPC for Vermont businesses, farms, and institutions. In Vermont the economics of a commercial array up to 500 kW are set by PUC Rule 5.100 net-metering: a statewide blended rate of $0.2071 per kWh from August 1, 2026, adjusted by siting and REC adjustors that reward preferred sites and penalize everything else.

That makes site selection the first engineering decision, not the last. We scope rooftops, parking canopies, and previously developed land that qualify as preferred sites, carry the project through utility interconnection and the Certificate of Public Good, and then build and maintain it.

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Last reviewed: September 2026. Net-metering rates and adjustors reflect the Vermont PUC 2026 biennial update order (Case No. 26-0291-INV). Confirm current values with the Vermont Public Utility Commission and your utility before relying on any figure.

How Vermont net-metering values a commercial system

Vermont net-metering is governed by Public Utility Commission Rule 5.100. A net-metering system can be up to 500 kW. Compensation is built from three pieces: the statewide blended residential rate, a siting adjustor based on system category and location, and a REC adjustor based on whether the owner transfers the renewable energy credits to the utility or keeps them.

The PUC resets these values every two years. In its 2026 biennial update order dated May 29, 2026, effective for systems whose complete applications are filed on or after August 1, 2026, the Commission set the following:

Vermont net-metering values for new systems, effective August 1, 2026
ComponentDefinitionValue per kWh
Blended residential rateStatewide base rate$0.2071 (up from $0.18398)
Category I siting adjustor15 kW or lessnegative $0.05
Category II siting adjustorOver 15 kW to 150 kW, preferred sitenegative $0.05
Category III siting adjustorOver 150 kW to 500 kW, preferred sitenegative $0.07
Category IV siting adjustorOver 15 kW to 150 kW, not on a preferred sitenegative $0.08
REC adjustor, RECs transferred to utilityAll categories$0.00
REC adjustor, RECs retained by ownerAll categoriesnegative $0.04

Under the rule, a zero or positive adjustor applies for 10 years from commissioning, while a negative adjustor applies in perpetuity. Every adjustor in the current schedule is zero or negative, so the permanent haircut is part of the long-term model.

Two structural points follow from the category definitions. First, there is no category for a system over 150 kW that is not on a preferred site, so a large ground mount on open farmland cannot net-meter at all. Second, a Category III system transferring its RECs is credited on the basis of the blended rate less $0.07, which is the number we test against the host's actual retail rate when deciding how much of the output should be consumed on site.

Why the REC choice matters. Retaining RECs costs $0.04 per kWh for the life of the system. Most commercial owners transfer them to the utility unless they have a specific claim they need to make about renewable electricity use; making that claim without the RECs is not supportable. We model both cases.

Siting

Preferred sites: where commercial solar pencils in Vermont

Rule 5.100 lists the preferred site types that unlock Categories II and III. For commercial owners the relevant ones are:

  • Roofs and other constructed impervious surfaces. The simplest path, and roof-mounted solar of any size up to 500 kW registers rather than applies (see below).
  • Parking lot canopies. Carports over existing parking qualify and add covered parking and snow protection. See solar carports.
  • Previously developed tracts, brownfields, sanitary landfills, gravel pits, and quarries. Disturbed land that the state prefers to reuse.
  • Sites designated by the municipality in a joint letter or plan, and certain federal Superfund list sites.
  • Parcels on or adjoining the host customer where the customer takes at least 50 percent of the output.

The Vermont Department of Environmental Conservation also maintains a list of contaminated sites that can support a preferred site designation. We confirm the category early because it sets both the compensation and the permitting path.

Certificate of Public Good: registration or application

Every net-metering system in Vermont needs a Certificate of Public Good (CPG) from the PUC, filed through the ePUC system. Since March 1, 2024, Green Mountain Power uses a two-part process: the customer first obtains interconnection approval from the utility under Rule 5.500, then files the CPG with the Commission.

  • Registration (Rule 5.105). Roof-mounted solar of any capacity up to 500 kW, ground-mounted solar of 15 kW or less, hydroelectric systems, and mixed systems where the ground-mounted portion is 15 kW or less. This is a faster, lighter filing.
  • Application (Rule 5.106). Ground-mounted solar over 15 kW up to 500 kW, and non-solar systems. The applicant must send an advance submission to the municipality, regional planning commission, adjoining landowners, and state agencies at least 45 days before filing, and the Commission considers aesthetics, natural resources, and orderly development.
  • Above 500 kW. Projects no longer qualify for net-metering and proceed under 30 V.S.A. section 248, typically with a Standard Offer contract or a negotiated power purchase agreement.

The practical implication is that a commercial rooftop is materially easier to permit in Vermont than an equivalent ground mount. For a canopy or ground array, we build the 45-day notice, site plan, and screening plan into the schedule before we commit to a construction date.

Utilities and interconnection

Vermont has several distribution utilities, and interconnection rules and tariffs vary among them. Four matter most for commercial projects:

Main Vermont distribution utilities for commercial solar
UtilityTerritoryNotes for commercial projects
Green Mountain Power (GMP)Most of the state, including Rutland, Montpelier, and much of Chittenden CountyPublishes a solar map for feasibility, a three-phase service map, and a daily distributed generation project list. Review times of 15 or 31 days depending on size.
Vermont Electric Cooperative (VEC)Northern VermontMember-owned cooperative with its own interconnection and net-metering tariffs; rural feeders can be capacity constrained.
Burlington Electric Department (BED)City of BurlingtonMunicipal utility; dense commercial rooftops and parking structures.
Washington Electric Cooperative (WEC)Central VermontSmall member-owned cooperative; confirm three-phase availability and circuit capacity early.

Interconnection is governed statewide by PUC Rule 5.500. In GMP territory, systems over 15 kW submit a Rule 5.500 application to the utility first. GMP's published response times are 15 days for systems up to 25 kW and 31 days for larger systems up to 500 kW. Some Vermont circuits have limited capacity for new generation, and the GMP solar map is the starting point for screening a site. Where a feeder is constrained we evaluate export limiting or pairing with storage rather than accepting an upgrade cost blind.

One recent rule change affects campus and multi-building owners: group net-metering systems must now be located on the same parcel as, or a parcel adjacent to, the group members, with a narrow exception for low-income multifamily housing.

Above 500 kW

The Standard Offer program

Vermont's Standard Offer program, established in 2009 under 30 V.S.A. section 8005a, awards long-term fixed-price contracts to renewable plants up to 2.2 MW. Capacity is allocated through annual requests for proposals run by the Standard Offer Facilitator, with the lowest-priced bids winning. The PUC sets technology-specific price caps each cycle based on avoided cost.

For a landowner or developer with a site larger than net-metering allows, the Standard Offer is the main route to a contracted revenue stream, though the capacity offered each year is small and competition on price is real. We do not publish a 2026 price cap here; confirm the current RFP schedule, capacity, and caps with the Vermont PUC and the Standard Offer Facilitator. Our solar farm EPC services and bankable solar farm EPC guide cover how we build to lender standards for this kind of project.

Taxes and federal incentives

Uniform capacity tax

Vermont replaces much of the usual property tax on solar equipment with a state uniform capacity tax under 32 V.S.A. section 8701. Solar plants of 50 kW or more pay $4.00 per kW of plant capacity per year, filed on Form SCT-603 and due April 15 of the following year. Solar plants under 50 kW are exempt from this tax. The tax applies to the fixtures and personal property of the plant, not the underlying land, which remains taxed as before. Standalone storage of 600 kWh or more that is not connected to a renewable plant pays $0.50 per kWh of energy rating.

For a 400 kW rooftop, that is $1,600 per year, a known and fixed line in the operating budget rather than a local assessment that can move.

Federal Section 48E credit and depreciation

The clean electricity investment credit is 6 percent base and 30 percent for facilities under 1 MW AC net output or those meeting prevailing wage and apprenticeship requirements. Under the One Big Beautiful Bill Act (enacted July 4, 2025), solar facilities that began construction on or before July 4, 2026 are not subject to the 2027 placed-in-service deadline, subject to continuity rules; facilities beginning construction after July 4, 2026 must be placed in service by December 31, 2027. Given Vermont's CPG timelines and winter season, a project starting now needs a disciplined schedule. See our federal ITC guide. Commercial solar is 5-year MACRS property, and 100 percent bonus depreciation was made permanent in 2025.

Designing for Vermont snow and terrain

Vermont design ground snow loads are among the highest in our service area and vary sharply with elevation, so a figure from one town cannot be reused in the next valley. Commercial structures are subject to the state Fire and Building Safety Code and ASCE 7 snow provisions.

  • Structural review before layout. Barns, older mills, and ski-area buildings often have limited reserve capacity. Drift at parapets and roof steps is checked explicitly.
  • Ground clearance and tilt. On ground mounts and canopies we set the lower edge high enough to clear shed snow, and steeper tilt improves both shedding and winter yield.
  • Cold-weather electrical design. Strings are sized to site record lows so inverter voltage limits are respected on the coldest mornings.
  • Realistic winter production. The energy model includes snow cover losses from December through March, which matters for a net-metering account where credits carry forward only within the rule's limits.
Fit

Where commercial solar and storage work in Vermont

Manufacturing and food production

Dairy processing, breweries, and specialty food makers carry steady daytime load on large roofs that register as preferred sites. See solar for manufacturers.

Hospitality and resorts

Inns and ski resorts pair winter heating and snowmaking loads with summer tourism; carports over guest parking are preferred sites. See hospitality solar.

Schools, colleges, and nonprofits

Tax-exempt owners can use a third-party PPA or lease, or federal elective pay where eligible. See nonprofit solar.

Cold storage and agriculture

Refrigeration load peaks with summer production. See cold storage solar.

Battery storage adds value where a commercial account carries demand charges, where a feeder limits export, or where the site needs backup power through winter storms. We size batteries from 15-minute interval data and the utility's rate schedule, and confirm any utility storage program terms directly with GMP or the relevant cooperative. See our commercial battery storage services.

Questions

Frequently asked questions

What is the largest commercial solar system that can net-meter in Vermont?

500 kW. Under PUC Rule 5.100, systems over 150 kW up to 500 kW must be on a preferred site (Category III). Systems over 15 kW up to 150 kW can be on a non-preferred site (Category IV) but receive a larger negative siting adjustor. Above 500 kW, projects proceed under 30 V.S.A. section 248, typically with a Standard Offer contract or a negotiated PPA.

What are the Vermont net-metering rates for new systems in 2026?

For complete applications filed on or after August 1, 2026, the PUC set a blended residential rate of $0.2071 per kWh, siting adjustors of negative $0.05 for Categories I and II, negative $0.07 for Category III, and negative $0.08 for Category IV, and a REC adjustor of $0.00 if RECs are transferred to the utility or negative $0.04 if retained. Negative adjustors apply in perpetuity.

Does a commercial rooftop system in Vermont need a full CPG application?

No. Roof-mounted solar of any capacity up to 500 kW uses the registration process under Rule 5.105 after utility interconnection approval. Ground-mounted solar over 15 kW requires a full application under Rule 5.106, including a 45-day advance submission to the town, regional planning commission, adjoining landowners, and state agencies.

How is commercial solar taxed in Vermont?

Solar plants of 50 kW or more pay the state uniform capacity tax of $4.00 per kW per year under 32 V.S.A. section 8701, filed by April 15 of the following year. Plants under 50 kW are exempt from that tax. The tax covers the plant's fixtures and personal property, not the land, which is taxed as before.

What is a preferred site in Vermont?

Rule 5.100 lists preferred sites including roofs and other constructed impervious surfaces, parking lot canopies, previously developed tracts, brownfields, sanitary landfills, gravel pits and quarries, municipally designated sites, certain federal Superfund sites, and parcels on or adjoining a customer taking at least 50 percent of the output. Preferred sites qualify for better siting adjustors and allow systems over 150 kW.

Sources

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