Explore the largest hydro power plants in ISO-NE and see all the utility-scale hydro projects in ISO-NE on a map.
Last updated: May 2026
On this page, you can explore our real-time database of hydro power plants in ISO-NE. Each month, we track hydro projects and update our list of the largest hydro power plants in ISO-NE.
As of May 2026, there are 179 utility-scale hydro power plants in ISO-NE, according to Cleanview's project tracker. Their total operating capacity is 3,791 MW.
Total Hydro Power Plants
179
Total Capacity
3,791 MW
Built in 2025
0
Map of hydro power plants in ISO-NE. Marker size reflects capacity — only facilities with reported capacity data are shown.
1,168 MW
Year Operational: October 1973
Location: Franklin, Massachusetts
666 MW
Year Operational: October 1974
Location: Berkshire, Massachusetts
195 MW
Year Operational: October 2023
Location: Grafton, New Hampshire
168 MW
Year Operational: September 1930
Location: Grafton, New Hampshire
138 MW
Year Operational: July 1988
Location: Penobscot, Maine
76 MW
Year Operational: January 1955
Location: Somerset, Maine
72 MW
Year Operational: January 1940
Location: Somerset, Maine
62 MW
Year Operational: January 1917
Location: Franklin, Massachusetts
45 MW
Year Operational: October 1954
Location: Oxford, Maine
195 MW
Year Operational: October 2023
Location: Grafton, New Hampshire
2 MW
Year Operational: April 2016
Location: Windham, Vermont
1 MW
Year Operational: July 2014
Location: Berkshire, Massachusetts
4 MW
Year Operational: November 2013
Location: Penobscot, Maine
2 MW
Year Operational: September 2013
Location: Penobscot, Maine
12 MW
Year Operational: May 2012
Location: Franklin, Vermont
8 MW
Year Operational: November 2011
Location: Penobscot, Maine
3 MW
Year Operational: March 2009
Location: Penobscot, Maine
36 MW
Year Operational: April 2008
Location: Windham, Vermont
Cleanview