Feasibility Study Completed

Since December 2004, a team of staff scientists, engineers, and hydrologists have been researching the use of substratum intakes that could be drilled into the saline aquifer beneath Long Island Sound.  Led by EEA’s Dr. Roy Stoecker, the method will utilize the bottom of the Long Island Sound as a giant sand filter bed to result in an effective reduction of 100 percent in entrainment and impingement of marine life.  The network of directionally drilled well screens will capture saline groundwater from the sandy layers underneath the Sound to be used as cooling water.  Significant thermal efficiency benefits are thought to result from the availability of cooler water during the summer peak generating demand. The resulting study, the first of its kind, was recently completed and submitted to Keyspan.  Other members of the study team included:

• Michael K. McEachern, P.G. - MC Environmental,.
  Hydrogeology

• Robert Holzmacher, P.E.  J.R. Holzmacher P.E., LLC.
  Well and Hydraulic Engineering,

• James Rumbaugh, Environmental Solutions – Groundwater Modeling

This study determines the feasibility of pumping up to 700,000 gallons per minute from a Substratum Intake Structure (SIS) consisting of horizontal wells drilled beneath Long Island Sound from land on the Keyspan Northport (5,000MW) facility.  If the SIS proves to be feasible, it will provide both energy and regulatory compliance benefits over competing technologies without significant construction or operational environmental impacts.

ENR Gives Substratum Intake System a Boost

Only two weeks after presenting the Substratum Intake System to USEPA officials in Washington, Engineering News Record (ENR) provided some of that impetus when it reported in April that Keyspan scientists considered the concept promising.

“We’re grateful to ENR for the national press coverage” said Dr. Stoecker; “few people know that our system represents one of the few options to meeting the standards and the intent of EPA Regulations under 316 (a) and (b).  We hope the industries impacted under 316 will take the time to fully examine how effective the system can be without dealing a crushing blow to power generation efficiencies.  There are few win-win situations for both the economy and the environment in our business.  This, clearly, could be one of them”.  See ENR News Article.

The plan was to conduct the study in a phased, methodical, cost effective manner concentrating on the elements most likely to have possible fatal flaws before proceeding to the more straight forward engineering subtasks.  The overall major elements of this feasibility study are as follows:

• Hydrogeology Investigation

•  Groundwater Modeling

• Conceptual Engineering and Cost Projections

• Regulatory Agency Consultation

• Report and Recommendations for Future Studies

Over the past two years, Team staff scientists, engineers, and hydrologists have been researching the use of substratum intakes that could be drilled into the saline aquifer beneath Long Island Sound.  This method will utilize the bottom of the Long Island Sound as a giant sand filter bed to result in an effective reduction of 100 percent in entrainment and impingement of marine life.  This large network of directionally drilled well screens will capture saline groundwater from the sandy layers underneath the Long Island Sound to be used as cooling water.  Significant thermal efficiency benefits will also result from the availability of cooler water during the summer peak generating demand period.  Using water from a saline aquifer (as opposed to surface waters) has several obvious environmental and operational advantages:

• No entrainment of zooplankton or fish eggs and larvae.  Since the well screens are buried beneath the sand substrate no biological forms would be entrained into the plant.

• No impingement of adult fish and larger invertebrates on the traveling screens.

• No necessity for biocides since the incoming water will be essentially sterile.

•  No thermal plume during the summer months because the substrate water will be significantly colder than the surface waters.  This also obviates the need for additional circulation pumps as dilution water sources.

•  Increased thermal efficiency and reduced maintenance compared to surface water intake systems and greatly increased efficiency compared to cooling towers.

• Ability to quickly revert to surface water intake if necessary.

• Installation utilizing directional drilling with no marine environmental impacts.

• No major permits required (e.g., water well, tidal wetlands)

• Minimal alterations to present plant cooling system.

Conceptual Diagram of SIS - Substrate Intake System

Typical Northeast Power Plant