Middlesex County, Massachusetts: Power, Data Centers and the Local Economy
Home to Cambridge and Lowell, and the communities of Wakefield and Wilmington
Middlesex County is one of the places the data center build-out is physically happening. 2,488 MW has retired here since 2019, including Mystic Generating Station (natural gas, 1,744 MW, 2024). The SAVRN Data Center Map lists 22 data centers in Middlesex County, 42% of Massachusetts's total. Middlesex County is home to Cambridge, Lowell, Newton and Somerville, plus the unincorporated communities of Wakefield and Wilmington. The Moratorium Tracker holds 1 local measure here (0 in force); the latest is “Proposed temporary moratorium on data center applications”. 5 MW of new generation is planned here across 1 unit, led by Uriel Renovables S.A (battery storage), the 8th largest pipeline among Massachusetts's counties. 5 MW of it is already under construction or built.
Cities and towns in Middlesex County
Middlesex County is home to Cambridge, Lowell, Newton and Somerville, plus the unincorporated communities of Wakefield and Wilmington.
And 16 smaller places.
Unincorporated communities (governed by the county): Wakefield, Wilmington, Arlington, Ayer, Belmont, Burlington, Cochituate, Devens, East Pepperell, Groton, Hanscom AFB, Hopkinton, Hudson, Lexington, Littleton Common, Maynard, Pepperell, Pinehurst, Reading, Shirley, Stoneham, Townsend, West Concord, Winchester.
Residents are 2025 Census estimates for the part of each city, town or township inside this county. Census publishes no annual estimate for unincorporated communities.
What changed in Middlesex County
1st = the most. Ranks cover counties with a value on record.
| Measure | Then | Now | Change | Rank in Massachusetts |
|---|---|---|---|---|
| Population (2020 → 2025) | 1,624,461 | 1,669,979 | ▲ 2.8% | 1st of 14 by size |
| Total jobs (2019 → 2025) | 940,312 | 903,942 | ▼ 3.9% | 11th of 14 by growth |
| Average annual pay (2019 → 2025) | $89,467 | $118,479 | ▲ 32.4% | — |
| Construction jobs (2019 → 2025) | 42,318 | 41,820 | ▼ 1.2% | 7th of 8 by growth |
| Electrical contractor jobs (2019 → 2025) | 7,291 | 6,744 | ▼ 7.5% | — |
| Electric utility jobs (2019 → 2025) | 941 | 1,323 | ▲ 40.6% | — |
| Data processing and hosting jobs (2019 → 2025) | 3,136 | 2,775 | ▼ 11.5% | — |
| Unemployment rate (2019 → August 2026) | 2.4% | 4.0% | ▲ 1.6pts | — |
| Generating capacity added since 2019 | — | 121 MW | — | |
| Generating capacity retired since 2019 | — | 2,488 MW | — | |
| Planned generation (Aug 2026) | — | 5 MW | 1% of today's fleet | 8th of 8 by size |
Unemployment was 4.0% in August 2026, against 2.4% in 2019. 121 MW of that came online in 2019 or later, mostly natural gas. Construction employs 41,820, down 1.2% since 2019. Its power plants have 476 MW of capacity, 58% of it natural gas, the 10th largest fleet in Massachusetts. Employers here counted 903,942 jobs in 2025, down 3.9% from 2019. NSTAR Electric Company is the largest utility serving Middlesex County, one of 11 with territory here. Its residential customers paid an average 29.91¢/kWh in 2024, above the 16.18¢ median for Massachusetts utilities. Electrical contractors employ 6,744, down 7.5% since 2019 against up 3.4% statewide, at an average $103,316 a year. 1,669,979 people live here, up 2.8% since 2020, 1st of 14 Massachusetts counties by population.
Who powers Middlesex County
Net change in operating capacity since 2019: −2,367 MW. Colors follow the fuel legend above.
Utilities with service territory in Middlesex County
| Utility | Ownership | Service | Residential customers (systemwide) | Residential price, 2024 | Commercial share of sales |
|---|---|---|---|---|---|
| NSTAR Electric Company | Investor Owned | Bundled | 1,303,076 | 29.91¢ | 27% |
| Massachusetts Electric Co | Investor Owned | Bundled | 1,210,113 | 33.60¢ | 24% |
| Town of Reading - (MA) | Municipal | Bundled | 27,405 | 15.86¢ | 59% |
| Fitchburg Gas & Elec Light Co | Investor Owned | Bundled | 26,290 | 40.08¢ | 16% |
| Town of Hudson - (MA) | Municipal | Bundled | 11,448 | 13.39¢ | 19% |
| Town of Littleton - (MA) | Municipal | Bundled | 6,738 | 14.12¢ | 19% |
| Town of Belmont - (MA) | — | — | — | — | — |
| Town of Concord - (MA) | — | — | — | — | — |
Customer counts, prices and sales shares cover each utility's whole system in the state, not only this county. Commercial sales include data centers.
Operating power plants 59
| Technology | Capacity | Share |
|---|---|---|
| Natural gas | 276 MW | 58% |
| Solar | 106 MW | 22% |
| Battery storage | 42 MW | 9% |
| Petroleum | 27 MW | 6% |
| Hydro | 25 MW | 5% |
| Largest plants | Owner | Technology | MW | Since |
|---|---|---|---|---|
| Kendall Square Station | Kendall Green Energy, LLC | Natural gas | 235 MW | 1958 |
| Mass Inst Tech Cntrl Utilities/Cogen Plt | Massachusetts Inst of Tech | Natural gas | 43 MW | 2021 |
| Boott Hydropower | Boott Hydro, LLC - Hybrid | Hydro | 23 MW | 1985 |
| Cherry Street | Town of Hudson - (MA) | Natural gas | 13 MW | 1951 |
| Blodgett Solar CSG | Blodgett Street Solar 1, LLC | Solar | 10 MW | 2021 |
| Dunstable Solar 1, LLC | AES Distributed Energy | Battery storage | 9 MW | 2021 |
Planned generation 1
| Plant | Technology | MW | Status | Year | Owner |
|---|---|---|---|---|---|
| Framingham BESS | Batteries | 5 MW | Under construction (≤50%) | 2026 | Uriel Renovables S.A |
Retired since 2019
| Plant | Technology | MW | Year |
|---|---|---|---|
| Mystic Generating Station | Natural gas | 1,744 MW | 2024 |
| Mystic Generating Station | Petroleum | 631 MW | 2021 |
| Tanner Street Generation | Natural gas | 85 MW | 2024 |
| Mass Inst Tech Cntrl Utilities/Cogen Plt | Natural gas | 21 MW | 2021 |
The Middlesex County labor market
| Industry (2025) | Jobs | Average pay | Concentration vs U.S. |
|---|---|---|---|
| All industries | 903,942 | $118,479 | 1.00 |
| Construction | 41,820 | $106,846 | 0.87 |
| Electrical contractors | 6,744 | $103,316 | 1.03 |
| Electric utilities | 1,323 | $136,000 | 0.54 |
| Data processing and hosting | 2,775 | $191,549 | 0.99 |
Concentration is the BLS location quotient: 1.0 means the industry holds the same share of local jobs as it does nationally. Industry rows count private employers; cells BLS suppresses are left out.
Data centers and local rules in Middlesex County
22 data centers in Middlesex County are on the SAVRN Data Center Map.
Local measures 1
| Measure | Status | Date | |
|---|---|---|---|
| Proposed temporary moratorium on data center applications | Proposed | 2026-09 |
Middlesex County and its neighbors
Of the 5 counties that border Middlesex County, Worcester County carries the most build-out activity: data centers, planned generation and operating plants combined.
| County | Population | Jobs since 2019 | Operating MW | Planned MW | Data centers | Local measures |
|---|---|---|---|---|---|---|
| Middlesex County | 1,669,979 | ▼ 3.9% | 476 MW | 5 MW | 22 | 1 |
| Essex County | 826,653 | ▼ 0.1% | 1,154 MW | 5 MW | 3 | — |
| Hillsborough County NH | 433,415 | ▼ 3.2% | 63 MW | — | 8 | — |
| Norfolk County | 739,749 | ▼ 1.6% | 2,741 MW | 11 MW | 2 | — |
| Suffolk County | 791,891 | ▲ 1.3% | 269 MW | 250 MW | 6 | — |
| Worcester County | 888,502 | ▲ 0.9% | 1,956 MW | 205 MW | 8 | — |
More of Massachusetts
Middlesex County, answered from the record
Who provides electricity in Middlesex County, Massachusetts?
11 utilities have service territory in Middlesex County in the EIA-861 2024 report: NSTAR Electric Company, Massachusetts Electric Co, Town of Reading - (MA), Fitchburg Gas & Elec Light Co. The largest, NSTAR Electric Company, charged residential customers 29.91¢/kWh on average in 2024.
What county is Cambridge, MA in?
Cambridge is in Middlesex County, Massachusetts. About 122,588 people live there (2025 Census estimate).
What county is Lowell, MA in?
Lowell is in Middlesex County, Massachusetts. About 119,971 people live there (2025 Census estimate).
What county is Newton, MA in?
Newton is in Middlesex County, Massachusetts. About 90,741 people live there (2025 Census estimate).
What power plants are in Middlesex County?
59 operating plants with 476 MW of capacity. The largest is Kendall Square Station (235 MW, natural gas).
How much new power is planned in Middlesex County?
5 MW across 1 units in the August 2026 EIA-860M inventory, 5 MW of it under construction or built. The largest owner is Uriel Renovables S.A.
Are there data centers in Middlesex County?
Yes. The SAVRN Data Center Map lists 22 data centers in Middlesex County.
Is Middlesex County adding jobs?
Employers counted 903,942 jobs in 2025 against 940,312 in 2019 (-3.9%, BLS QCEW). Construction went from 42,318 to 41,820.
Does Middlesex County have a data center moratorium?
The SAVRN Moratorium Tracker holds 1 local measure for Middlesex County, 0 in force.