Lot 03 · The long read

The 100 percent question runs through a barn in Salisbury

Vermont has written a 100 percent renewable electricity requirement into law, the fastest timeline of any state. The national debate about that number is abstract. The farm end of it is not: it is a sealed tank, about 900 cows, and a pipeline tap in Addison County.

Flat geometric illustration of a Vermont dairy farm with a red barn, a large cylindrical digester tank, a pipe running to a small conditioning unit, a food-waste truck, and cows in the pasture — The working end of the standard: the Goodrich Farm digester in Salisbury turns manure and food waste into pipeline gas that Middlebury College buys under a 20-year agreement.

BY THE CLEAN ENERGY VERMONT EDITORS · FILED SEPTEMBER 27, 2026 · 8 MIN READ

Every Vermonter with a meter has a stake in the number 100, because the state's new renewable standard is not a voluntary pledge. It is a legal requirement with dates attached, and its compliance costs will move through the supply side of your bill over the next decade. The argument over whether that is worth it tends to happen in abstractions: targets, percentages, regional accounting. This story keeps to the concrete parts.

Start with the physical system the standard must feed. Vermont sits inside the six-state New England grid run by ISO New England, and New England is a net importer of electricity: on average, roughly 16 percent of the power consumed in the region from 2015 through 2024 arrived over lines from New York, Quebec, and the Canadian Maritimes, per the grid operator's own publications. Vermont utilities lean on that import path hardest in winter, when Quebec hydro runs steady and the state's own solar output is at its shortest days.

What the law actually says

In June 2024, the legislature overrode a gubernatorial veto to enact Act 179, which rewrote the state's renewable energy standard. The headline requirement: every retail electricity supplier in Vermont must supply 100 percent renewable electricity, with the state's largest utility, Green Mountain Power, held to 2030 and the smaller municipal and cooperative utilities given until 2035. The Department of Public Service and the Public Utility Commission administer and enforce the standard through utility filings.

There is a second tier that gets less press and may matter more. Beginning in 2025, utilities must meet an escalating share of their load growth above 2024 levels with renewable sources, on a schedule published by the commission. That load-growth tier is the part of the law designed to change what gets built, not just what gets bought. Utilities can also use renewable energy certificates, the market instruments that certify a megawatt-hour came from a qualifying source, which is why the standard's accounting and its physical reality are related but not identical.

The barn end of the equation

Drive to Salisbury, in the Champlain Valley south of Middlebury, and the load-growth tier stops being a regulatory term. Behind the Goodrich family dairy barn stands an anaerobic digester: sealed tanks where bacteria break down manure and food waste without oxygen, producing methane that is captured, cleaned to pipeline quality, and sold as renewable natural gas instead of escaping to the atmosphere from an open manure lagoon.

Per the developer Vanguard Renewables' project page, the facility takes in on the order of 65,700 tons of food waste and 36,500 tons of manure a year, the manure from a herd of roughly 900 cows, and puts out about 140,000 Mcf of renewable natural gas annually. Food and beverage waste arrives by truck from manufacturers and distributors around the region. When it entered service in the summer of 2021, partners billed it as the largest farm-based digester in the Northeast.

The offtake is what makes the project a small energy system rather than a waste contract. Vermont Gas Systems owns the interconnection equipment and takes the gas into its distribution pipes, and Middlebury College buys most of the output under a 20-year agreement that offsets part of the college's heating load. The farm gets lease income and a manure-management answer; the gas utility gets renewable supply; the college gets a hedge. That three-way structure is the model a small state has to work with: no single project moves the needle, but each one is legible, local, and checkable.

The hydro side of the ledger

Vermont's other great resource is a river system it does not own. Hydro-Quebec exports move into the state over high-voltage lines, and the scale shows up in municipal disclosures: Stowe Electric Department, for example, reports that about 21 percent of its 2024 supply came from Hydro-Quebec. Burlington, the state's largest city, has run a municipal utility on a wood, hydro, wind, and solar portfolio for decades and reports that renewable sources covered more than all of its 2024 load, an annual figure that says nothing about any given winter evening.

The regional picture frames how much room the standard has to work. The grid operator's statistics put natural gas, nuclear, hydro, imports, and renewables at the overwhelming majority of the six-state mix, with gas setting the marginal price most hours. When Quebec reservoirs are full and winter demand spikes, imports are New England's pressure valve; when they are not, ISO New England's winter reliability programs and oil inventories carry the risk. Either way, Vermont's 100 percent accounting rides on top of a shared physical grid it does not control.

What it means for your bill

This is where the reader's question lives, and the honest answer has two parts. First, the compliance costs of the standard land in supply rates, which the Public Utility Commission reviews in each utility's rate filings. Legislators acknowledged when the bill passed that the total cost was uncertain, because it depends on the future price of renewable supply, how fast load grows as heating and driving electrify, and how much new in-state construction the load-growth tier induces.

Second, the same law era has already produced tools that push the other direction. Green Mountain Power's home battery programs, a Powerwall lease at about $55 a month or a bring-your-own-device rebate for customer-owned batteries, enlist thousands of households as dispatchable capacity; regulators lifted the programs' enrollment caps in 2023 after repeated storm seasons. Batteries on the wall of a house in Rutland do not count in the standard the way a certificate does, but they do shave the evening peaks that make electricity expensive in the first place. Net-metered solar, efficiency programs, and weatherization sit in the same category: bill reducers that the accounting does not fully credit.

So the practical read on your statement over the next several years: watch the supply-rate line, compare it year over year rather than month to month, and weigh it against whatever you have done on the efficiency and storage side. The standard makes the supply cleaner on paper and somewhat more expensive; the home-side options are the offset Vermont actually gives you.

Worth watching this quarter

The Public Utility Commission's renewable standard filings and annual reports, the routine paperwork where compliance costs first become visible (routine, but it is where the number lives).
Green Mountain Power's long-range resource plan updates, which set out how the state's largest utility intends to meet the 2030 date.
Vermont Gas Systems' renewable gas contracting, which decides how much farm methane reaches the pipeline and whether more Salisbury-style digesters get built.
Winter import levels published by ISO New England, the region's annual stress test, most telling in January and February.
Mud-season outage data from the co-ops and municipal utilities, a practical early indicator of how the last mile of wire is holding up.

Common questions

What does Vermont's renewable standard actually require?

Act 179 of 2024 requires every electric utility in Vermont to supply 100 percent renewable electricity, with the largest utility held to 2030 and smaller municipal and cooperative utilities given until 2035. A separate tier requires an escalating share of each utility's load growth above 2024 levels to be met with renewable sources. Utilities may meet parts of the standard with renewable energy certificates, the market instruments that certify a megawatt-hour came from a qualifying source.

Does 100 percent renewable mean every hour of every day?

No. The standard is an annual accounting measure, not an hour-by-hour guarantee. On a windless winter night Vermont still draws on imports, existing hydro, and whatever else the regional grid has running. The policy changes what utilities buy over the year, not the physics of the wires.

How does a dairy farm make pipeline gas?

In an anaerobic digester, bacteria break down manure and food waste in sealed tanks without oxygen, producing methane that is captured instead of escaping to the atmosphere. The gas is cleaned to pipeline quality and injected into the local gas distribution system. At the Salisbury digester, roughly 900 cows supply the manure base and trucked-in food waste supplies the rest.

Who pays for the standard?

Ratepayers, through the supply side of their bills, since compliance costs land in the rates utilities charge. The Public Utility Commission reviews the filings. At last public debate, the total cost was genuinely uncertain: it depends on future renewable prices, how much load grows, and how much new in-state construction the load-growth tier induces.

What should a Vermonter actually watch?

The most readable signals are the Public Utility Commission's renewable standard filings and reports, each utility's long-range resource plan, and the supply-rate line on your own bill compared year over year. Winter import levels reported by the grid operator are the stress test worth checking each January and February.

Sources of record

Vermont Public Utility Commission, Renewable Energy Standard: the state regulator's own summary of the Act 179 requirements and the load-growth schedule.
Vermont General Assembly, H.289 (2024 session): the enrolled bill, including its veto-override history in June 2024.
ISO New England, resource mix and key statistics: the six-state grid operator's accounting of supply and interconnection flows.
Vanguard Renewables, Goodrich Farm project page: the digester developer's published inputs and renewable gas output.
Green Mountain Power, battery program filing news: the utility's own account of the program caps and terms later lifted by regulators.
Bolton Valley, resort fact sheet: the ski area's own figures for its summit wind turbine.

Back to the town plat