Green Amherst

Amherst College Cogeneration Plant

Project Description

Amherst College's cogeneration system will consist of a 1250-kW gas turbine generator that burns natural gas or diesel fuel. The turbine, similar in design to a small aircraft engine, will turn an electrical generator connected to the campus electrical system and send its hot exhaust to a heat recovery steam generator (HRSG).

Cogen Slide
The HRSG can make steam directly from the hot turbine exhaust, or burn additional fuel to make more steam to satisfy campus heat loads and keep the existing boilers off-line.

A 500-kW steam turbine will also be installed as part of the project, generating electricity by taking the high-pressure steam produced by the HRSG and boilers and reducing the pressure for campus distribution. Previously, this pressure reduction was performed by valves under the old heating plant.

The cogeneration system will occupy the space reserved for a future boiler in the existing heating plant, and a small addition has been created to house the turbines.

The cogeneration system will supply approximately 50% of our peak electrical load, and 67% of the annual electricity usage. We will purchase the rest from the local utility as usual. The steam output will satisfy approximately 30% of the campus heating needs, with the existing boilers used to supply the rest.

The overall reduction in source energy will substantially reduce the campus carbon emissions. Other emissions, such as NOx and SO2 that cause smog and acid rain, will be greatly reduced because of the cogeneration system's cleaner fuels and state-of-the-art pollution controls.

The cogeneration plant is expected to produce over 11 million kWh per year, enough to power 1,000 homes. The carbon reduction will be more than 22,000 tons of CO2, approximately 20% of the College's pre-cogen greenhouse gas footprint.

System Capacity

Cogen Gas Turbine


  • Gas turbine: 1250 kW
  • Steam turbine: 500 kW
  • Total electrical output: 1750 kW
  • Total annual output: 12,000,000 kWh
  • Total CO2 saved by operating co-gen plant: 6,000 tons


  • Heat recovery steam generator: 8,000 to 20,000 lbs. of steam per hour


Projected Construction Cost


Soft Costs*


Total Project Cost


First Year Net Savings


Anticipated Return on Investment (ROI)


Simple Payback

Approx. 7 years

Cost Avoidance of 15,000 lb/hr Steam

Valued at $500,000

*Professional service fees, supervision


Cogen Plant
Gas Turbine
Cogeneration Plant
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Gas Turbine Engine: the heart of our combined heat-and-power plant

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GT Pipes
HRSG Front
Gas Turbine Pipes: This is not a screen saver.

Heat Recovery Steam Generator: the heat end of the combined heat-and-power deal

SCR Emissions Controls
Boiler Feed Pumps

Emissions Control NOx Reduction Unit: the smog saver

  New Boiler Feedwater Pumps: C3PO's cousins