On September 14, FERC approved ISO New England's first round of changes to the Day-Ahead Ancillary Services market. The changes take effect October 22.

If you've had a customer ask "didn't they fix that DASI thing?", here's the short answer. Yes, a little.

What FERC Approved

Four changes, filed jointly by ISO-NE and NEPOOL (Docket ER26-3176).

The big one: ISO-NE will lower its Forecast Energy Requirement. That's the grid operator's estimate of how much physical supply it needs lined up for the next day. The old calculation understated wind and solar. Those resources have historically cleared only about 40% of their forecast output in the day-ahead market, so ISO-NE was buying reserves to cover a gap that mostly didn't show up.

Less over-buying means lower cost. The change should reduce the amount of unnecessary reserve capacity ISO-NE purchases in the day-ahead market.

The other three are plumbing: a floor on the strike price (the threshold where a resource gets charged for not performing), a $3/MWh floor on the test ISO-NE uses to screen offers for market power, and removal of a credit that was paying certain day-ahead imports that didn't back it up in real time.

Now Do the Division

ISO-NE estimates the changes save about $23 million a year.

The market cost more than $900 million in its first year. By our running tally, cumulative incremental cost hit $921 million through January 2026, roughly 6.6 times ISO-NE's original $140 million annual estimate.

$23M Estimated annual savings from the FERC-approved changes
$900M+ Cost of the DASI market in its first year
~2.5% Approximate share of the problem addressed by the fix

$23 million against $900 million is about 2.5%. So it's real, and it's small. We're glad it happened. It doesn't change what a customer should expect to pay this winter.

Where the Rest of the Cost Is Showing Up

You can see it in Rhode Island right now. In its winter last resort filing (Docket 26-27-EL), Rhode Island Energy's testimony lists ancillary services first among the three reasons winter rates are higher.

Per Uprise RI's reporting on the company's PUC materials, the estimated ancillary cost went from $4.09 to $10.38/MWh, up 154%. That cost is inside the 16.581 cent commercial fixed rate that's scheduled to start Wednesday, October 1.

The PUC still hadn't issued its order as of this morning, so the rate is technically proposed, but the Division recommended approval as filed.

Massachusetts is seeing the same wholesale pressure. National Grid's medium and large C&I default goes from 10.7–11.0 cents to 21.7–21.9 cents on November 1. That's roughly double today and up 26–27% on last winter's 17.3–17.4 cents. Eversource hasn't posted its November number for those customers yet.

And Gas Stopped Helping This Week

For most of September, cheap gas was the one thing that argued for patience. That changed.

  • Henry Hub hit $3.20 on September 24, its highest since early July, after a pipeline force majeure in Appalachia. It's at $3.11 this morning (front-month quote via Trading Economics), up about 7% from a week and a half ago.
  • The storage surplus over the five-year average fell from 118 Bcf to 95 Bcf in a single weekly report.
  • NOAA's 8–14 day outlook has every New England state leaning below normal for October 5–11.
  • Heating oil futures, the proxy for New England's backup fuel when gas gets tight in a cold snap, are up about 103% from a year ago.

None of that is a crisis. Together, it's the end of the quiet window.

What to Do With It

  • Anything renewing with this December through February in the term: Gridwealth recommends Winter Flex. That's where the utility schedules, gas basis and oil risk all peak.
  • Index and full-passthrough customers: assume winter DASI costs look like last winter's. If they want to stay market-exposed, Gridwealth's Fixed with DASI Adjustable structure fixes the energy price and passes through actual DASI charges, so any future reform savings go to them.
  • National Grid and Eversource medium and large C&I on default: quote Winter Flex, or Fixed All-In through at least March 2027 if they need one number, before November 1. Going longer than winter? Fixed with Capacity Passthrough.
  • Rhode Island customers on last resort service: call this week. Customers can still move after October 1; the conversation just gets harder once the new rate is on the bill.
  • Small businesses on a utility variable rate: October is near the bottom of every published Massachusetts schedule. January is more than double — Unitil G1 hits 31.0 cents.

Run the Numbers on a Specific Account

Use Gridwealth's DASI Bill Shock Estimator to show customers their potential winter exposure, or request a quote from your Gridwealth representative.

DASI Bill Shock Estimator → Request a Quote →

Every utility rate in this post was checked against the utility's own rate page on September 28, 2026. Sources: Washington Energy Report summary of FERC's September 2026 DASI order (ER26-3176); Uprise RI; ISO-NE DASI key project page; RIPUC Docket 26-27-EL; National Grid rate tables; EIA Weekly Natural Gas Storage Report (week ending 9/18/2026); Trading Economics; NOAA Climate Prediction Center (issued 9/27/2026).

This post is market commentary, not financial advice. Contact your Gridwealth representative for binding pricing.