On September 9, 2026, Acadia Center published a fact sheet titled “Regional Greenhouse Gas Initiative (RGGI) Impacts in ISO New England: Setting the Record Straight on Costs and Benefits.” Its “bottom line” is that RGGI is a $4-to-1 winner for New England ratepayers — $445 million in 2025 auction proceeds projected to return $1.3 billion in lifetime energy-bill savings, comfortably beating the $815 million ISO-NE estimates RGGI added to 2025 wholesale costs. The fact sheet closes by urging ISO-NE states to keep championing the program and to finish implementing the Third Program Review’s tighter caps.
I have spent the summer documenting exactly this kind of accounting in New York, where the Department of Environmental Conservation (DEC) and New York State Energy Research & Development Authority (NYSERDA) defended the same Third Program Review amendments with a “nearly 6-to-1” ratepayer savings ratio. Acadia’s fact sheet uses the identical structure — a modeled, lifetime, participant-side savings figure set against a single year of narrowly defined cost — and it does so in the same week that RGGI’s own auction results undercut its “manageable costs” framing. Setting the record straight requires looking at both halves of the ledger, not just the half that makes the program look good.
I have been involved in the RGGI program process since its inception and have been writing about problems with the RGGI program here. I have worked on every cap-and-trade program affecting electric generating facilities in New York including RGGI, the Acid Rain Program, and several Nitrogen Oxide programs, since the inception of those programs. The opinions expressed in this post do not reflect the position of any of my previous employers or any other organization I have been associated with. These comments are mine alone. I acknowledge the use of Perplexity AI to generate material included in this document.
Bad timing: Auction 73 landed the same day
Acadia’s fact sheet is dated September 9, 2026 — the same day RGGI held Auction 73. The results came out two days later: a clearing price of $37.65 per allowance, up $2.65 from Auction 72’s $35.00 record set just three months earlier, and up 296 percent from the $9.30 clearing price at the first full auction of Governor Hochul’s tenure in September 2021. The top bid at Auction 73 was $190 per allowance — five times the clearing price — which is not what a market in balance looks like. I covered this in RGGI Auction 73: The Clearing Price Question Is Answered, following up on RGGI Update and the Auction Clearing Price Question.
Acadia’s fact sheet was written before the auction set its second consecutive record high, with the program’s own price-relief mechanism — the Cost Containment Reserve (CCR) — already exhausted for the year by the March 2026 auction. A fact sheet arguing that RGGI’s costs are modest and well-managed needed to grapple with that trajectory. It doesn’t mention it at all.
The core accounting problem: modeled lifetime savings vs. one year of cost
Acadia’s $1.3 billion savings figure is explicitly a projection, not a measured result. Its own Endnote 3 says so: “2025 investment and outcomes data are not yet available, this analysis applies real data from [the] 2024 report”. The reports calculates the ratio of proceeds each state invested in each program category, and the lifetime savings each ratio historically returned — to 2025’s actual proceeds total. In other words, Acadia took last year’s return ratios and multiplied them by this year’s revenue. That’s a projection built on an assumption of continuity, not a report of what actually happened.
This is the same structural move the DEC and NYSERDA made when they defended New York’s RGGI amendments with a “nearly 6-to-1” ratio: $12.334 billion in what NYSERDA itself labels “Energy Bill Savings to Participating Customers” against $2.188 billion invested. When I went through the Technical Support Document behind that number, the qualifications mattered enormously. The $12.334 billion figure is a modeled, expected-lifetime estimate. It includes projects still in the pipeline that are not yet operational. It has generally not been adjusted through evaluation, measurement, and verification (EM&V). And it is compared only against historical program expenditures, not against the revenues collected or the program’s full cost. Acadia’s multipliers — 4.5x for energy efficiency, 8.2x for clean energy, 1.22x for electrification, 1.0x for bill assistance — are the same kind of lifetime, model-derived ratio, applied here to a single year of proceeds rather than verified against actual outcomes.
Acadia also compares apples to oranges on the timing. The $1.3 billion is a lifetime figure — savings that compound over the 15-to-20-year measure life of efficiency and clean-energy programs. The $815 million cost is a single year, 2025 only value. Stacking a multi-year benefit stream against one year of cost is not a real return-on-investment calculation; it overstates the ratio by construction. A colleague of mine, who prefers to remain anonymous, framed the broader problem well: this kind of program takes a dollar from the consumer now and returns a fraction of that dollar’s value later, through delayed and partially administered programs — with people who don’t qualify, can’t front the upgrade cost, or don’t navigate the application process absorbing the shortfall in full, indefinitely. Discount a delayed, diminished, partially realized return to present value, and Acadia’s 4-to-1 ratio — like NYSERDA’s 6-to-1 — looks considerably less generous than advertised.
The missing piece: the wholesale-market cost adder
Acadia’s entire cost side of the ledger is ISO-NE’s estimate that carbon pricing programs added $815 million to New England’s 2025 wholesale electricity costs, or roughly $55 per household per year. ISO-NE’s own 2025 Annual Markets Report is worth reading directly here, because it confirms the mechanism I have been documenting in New York: the wholesale-market cost of carbon compliance is larger than the direct cost of the allowances themselves. ISO-NE’s report separately estimates the direct cost of carbon allowances purchased — based on spot allowance prices — at about $668 million, versus the roughly $1.1 billion (all carbon programs) added to total energy market costs. The report explains why those two numbers differ: “the total cost of carbon allowances is lower than the total cost to the energy market because when fossil fuel-fired generators are on the margin, the inclusion of carbon costs raises the market clearing price” paid to every dispatched resource in that interval — not just the unit that bought the allowance.
ISO-NE’s own numbers show the same markup that I found in New York — roughly a 65 percent gap between the $668 million direct allowance cost and the $1.1 billion total energy-market effect for 2025. Acadia cites the $815 million RGGI-specific share of that already-marked-up total as its entire cost figure, which is more honest than counting direct allowance purchases alone. But it still stops at the energy-market adder ISO-NE models. It does not address capacity-market or other second-order effects, and it treats that single number as the full and final cost against which a multi-year, multi-program savings projection should be judged. If the wholesale mechanism is real enough for ISO-NE to model explicitly, it deserves more scrutiny than a single citation before being set against a rosy, projected benefit.
There’s also a regional wrinkle Acadia doesn’t address: this cost doesn’t stay inside RGGI’s borders. I looked at this question for New Hampshire’s potential exit from RGGI and found that even a state that leaves the program, or a ratepayer who receives no direct benefit from RGGI-funded programs, still pays an embedded RGGI cost on any imported electricity from RGGI-compliant states, because the marginal generator setting the regional clearing price is often RGGI-covered. Cost and benefit are not neatly contained within each state’s own ledger the way Acadia’s state-by-state table implies.
Averages hide who actually pays and who actually benefits
Acadia’s own Table 2 shows the “4-to-1” story doesn’t hold uniformly. Vermont receives $9.45 million in proceeds and shows zero recorded clean-energy or electrification savings in the table — its entire $42.1 million total comes from the energy-efficiency category alone. New Hampshire gets $65 million in direct bill assistance and comparatively little efficiency benefit relative to its proceeds. Massachusetts, with the largest efficiency infrastructure, drives most of the region’s projected savings. The multipliers Acadia uses aren’t universal constants. Instead, they depend entirely on which category a state’s dollars land in and how mature that state’s program infrastructure already is.
That variance matters because the cost side doesn’t vary the same way. The $4-to-5-per-month wholesale cost adder is charged to every ratepayer, uniformly, embedded in the price of every kilowatt-hour, whether or not that household ever benefits from an efficiency rebate or a bill-assistance program. The offsetting “savings” are conditional on eligibility, program capacity, and successful completion of an application process. A household that doesn’t qualify for a program, can’t front the money for an efficiency upgrade, or doesn’t live in a service territory where a credit applies still pays the RGGI-driven cost in full, with nothing returned. Averaging across six states and four program categories smooths over exactly the distributional problem that determines whether any individual ratepayer actually comes out ahead.
How much of the 37 percent reduction is actually RGGI?
Acadia states plainly that RGGI “has driven CO2 reductions of 37% since 2001 across New England power plants,” and repeats the claim in its conclusions. Firstly, RGGI started in 2009 so RGGI had no impact until then. Secondly, I’ve run the equivalent calculation for New York, using the state’s own reported cumulative program benefits, and found that RGGI-funded investments and programs account for only about 4.7 to 8.7 percent of the observed power-sector CO2 reduction since the program began. The overwhelming majority of the historical reduction is attributable to fuel switching from coal and oil to lower-emitting natural gas — a transition that happened for reasons largely unrelated to RGGI’s reinvestment programs, and one that offers little room to repeat.
Acadia’s own Table 3 makes the same point for New England, probably without meaning to. It shows natural gas now accounts for 95.4 percent of RGGI-covered CO2 emissions in ISO-NE, with oil contributing just 3.7 percent. The coal-to-gas switch that produced most of the historical emissions decline has already happened; there’s essentially no coal left to switch away from in this region. Which raises the obvious question Acadia doesn’t ask: if further RGGI-covered emissions reductions now require displacing gas generation directly, rather than riding a fuel-switching wave that has already run its course, what is the actual mechanism — and cost — of the next round of reductions the program claims credit for? A 37 percent historical reduction that mostly happened for other reasons isn’t a reason to expect the next 37 percent to come as easily, or as cheaply.
The oil-burn section: refuting an argument nobody serious is making
Acadia devotes a full page to rebutting the idea that New England’s wintertime oil burn is the primary driver of RGGI costs, concluding — correctly, based on their Table 3 — that natural gas is responsible for 26 times more RGGI-covered emissions than oil in 2025. That’s a fine technical point, but it isn’t the critique that matters. The substantive concern with RGGI, in New York and everywhere else, is the allowance price trajectory and the wholesale-market mechanism that embeds that price into every consumer’s bill — not the fuel mix of the marginal generator in any given hour. Spending a full section rebutting a weaker, secondary claim about oil, while never engaging the allowance-price-and-market-mechanism critique that program skeptics actually make, is a rhetorical choice. It answers a question nobody serious is asking instead of the one that’s actually on the table.
It’s also worth noting, in passing, what Table 3’s own footnote admits: wood and refuse-derived generation are exempt from RGGI’s cap entirely, despite being more emissions-intensive per megawatt-hour than oil and producing more electricity than oil in New England — 2,012 GWh and 2,563 GWh respectively, against oil’s 1,147 GWh. A cap that carves out fuels more emissions-intensive than the one being singled out for scrutiny is not the airtight accounting Acadia’s framing implies.
The cap trajectory: “manageable” is getting harder to say with a straight face
Acadia’s closing recommendation is that ISO-NE states should keep championing RGGI and finish implementing the Third Program Review’s steeper caps. That recommendation doesn’t engage with what’s happening in the allowance market right now. RGGI’s own price-relief valve, the Cost Containment Reserve, was fully exhausted for 2026 by the March auction — months before the year’s compliance deadline. The Auction 73 clearing price exceeds the 2036 CCR1 trigger price and the 2030 CCR2 trigger price and that suggests that in future years both CCR allocations will be exhausted in the first quarterly auction. That means the CCR will not meaningfully reduce costs. On August 21, 2026, RGGI’s independent market monitor, Potomac Economics, released an unprecedented special report on the second-quarter 2026 supply-demand balance, roughly eleven weeks after the Auction 72 price spike, apparently to reassure the market. Instead, it confirmed that compliance entities and investors are increasingly hoarding allowances rather than selling them as compliance deadlines approach, that investors hold 68 percent of the allowance surplus with no obligation to sell below whatever price the market has already shown it will bear, and that Virginia’s return to the program (it resumed participation July 1, 2026) adds less new supply than the new demand it represents. Most tellingly, the report explicitly declined to address whether the Third Program Review’s post-2027 cap trajectory — more than 10 percent annual reductions in the regional budget from 2027 through 2033, a pace the program has never sustained historically — is even sustainable, calling that question “beyond the scope” of the report.
Auction 73 answered the question the market monitor wouldn’t. The cap tightens further, the CCR is gone for the year, Virginia is a net new claim on the allowance bank rather than a source of relief, and the price cleared at a record $37.65 anyway, on one of the largest single allowance offerings in the program’s history. If the tool specifically designed to prevent this kind of price escalation is already exhausted, and the program’s own independent monitor won’t vouch for the tightening path immediately ahead, then “continue to champion the program and keep tightening the cap” is not the reassuring, record-straightening conclusion Acadia presents it as.
What would actually set the record straight
Proponents of RGGI claim the program has been a success. It’s an argument that this program’s accounting doesn’t support the “clear win for ratepayers, no real cost” story currently being told about it — in New York, and now in New England. If RGGI states and their advocates want to demonstrate a real, net ratepayer benefit rather than a modeled one, three things would help: publish realized, EM&V-verified savings instead of projected lifetime estimates built on the prior year’s ratios; have ISO-NE and NYISO calculate the full wholesale-market cost adder using the hourly dispatch data only grid operators have, rather than relying on a single annual estimate cited without independent scrutiny; and report the cost per ton of CO2 actually achieved through RGGI-specific investment, isolated from the fuel-switching-driven reductions that occurred for entirely separate reasons. Acadia’s own fuel-mix data shows have largely already happened. Until that accounting exists, an aggregate, multi-year “4-to-1” ratio measured against one year of narrowly scoped cost is not setting the record straight. It’s the same rhetorical move New York regulators made with a bigger number, dressed for a different region.
Pragmatic Environmentalist of New York 