Environmental Consulting & Engineering Services - from Concept to Reality

Case Studies


Athens Generating Power Plant

ESS was the lead environmental consultant for siting and construction of the 1100 MW Athens Generating Power Plant. This gas fired, combined cycle electric generation facility was the first major, merchant electric generation facility to be proposed in New York and the first to be certified under Article X of the New York State Public Service Law. Today, ESS continues to provide compliance support for the plant’s annual environmental reporting and operating permit renewals. The plant is located in Athens, New York.


Situated in the historic Hudson River Valley, Athens Generating presented a unique challenge - how to fulfil the needs identified in New York State’s Energy Plan by integrating a new power plant within a rural community while preserving the integrity of surrounding natural and cultural resources. During siting analyses, the Project team selected a parcel zoned for industry that was also proximal to major electric and natural gas transmission interconnections and water supply from the Hudson River. ESS then worked to identify natural resources and sensitive receptors in the Project Area so Project engineers could locate the plant and interconnections in a manner that minimized impacts to surrounding ecosystems and the community to the greatest extent practicable.

Technical Studies

ESS has conducted/managed extensive field investigations, technical studies, quantitative modelling, and data analysis to assess the plant’s potential impacts to air quality, aquatic and terrestrial ecology, wetlands, water quality and quantity, visual and cultural resources, noise, traffic, land use, and other impacts. These technical studies include air dispersion modelling, visual simulations and viewshed analyses, discharge plume modelling, entrainment/impingement modelling, and a human health risk assessment for combustion turbines and cooling tower emissions.

Engineering & Design

ESS worked with the Project team during plant development and continues to advise plant operators in the evaluation and selection of Best Available Control Technologies for the plant design. These include protective screening on the intake structure to minimize fish impacts and a continuous emissions monitoring system (CEMS) to confirm compliance with the facility’s emission standards for nitrogen oxides (NOX), carbon monoxide (CO), and ammonia (NH3). During development, ESS also provided dredging design / engineering for the intake structure, including recommended construction methods and alternatives for dredged material disposal.

Permitting & Compliance

ESS was responsible for preparation of all federal, state, and local environmental permit applications required for the Project. In addition to the comprehensive environmental reports required under Article X, these included: a State Pollution Discharge Elimination System (SPDES) permit; Title V air permit; wetland and water quality approvals under the Clean Water Act; Section 106 Historic Preservation Act reviews, state and federal Endangered and Protected species reviews; and dredging approvals for installation of the in-river water supply intake facility. ESS attended dozens of agency consultations and public hearings and presented expert testimony in adjudicated Siting Board proceedings regarding the scientific research and technical analyses conducted for the project.

Inspection & Monitoring

ESS provided on-site environmental monitoring during construction to ensure that work was conducted as specified in permit conditions to mitigate potential environmental impacts. Post-construction, ESS assisted with implementation and monitoring of natural resource area restoration, which included a wetland mapping and protection plan, creation of four new wetlands, a tree protection plan, and on-going sediment and water quality testing.

Outcome & Benefits

Athens Generating successfully received approvals and has been in commercial operation since 2004, ccontributing to electric reliability in the Mid-Hudson Valley, southeastern New York and the New York City regions.   ESS continues to provide environmental support for plant operations, including quarterly air quality monitoring, permit reporting, and renewals to demonstrate the facility’s compliance with permit conditions. Relative accuracy test audits (RATA) are conducted to maintain certification of the O2, CO, and NOX CEMS at the facility. ESS also completes an annual NH3 compliance test and was called upon to provide air quality modelling to support facility modifications that improved cold weather plant efficiency.