The Illinois Environmental Protection Agency is out for comment until Nov. 30 on a Section 401 Clean Water Act permit application from Northern Illinois Hydropower LLC related to the construction of a new powerhouse at the Dresden Island Lock and Dam at river mile 271.5 of the Illinois River in Grundy County, Illinois.
The applicant is proposing to install a turbine/generator system in the power station, which would create approximately 60,000 megawatt hour (MWh) of power. The design will comply with requirements set forth by Illinois Department of Natural Resources (IDNR) and Illinois Environmental Protection Agency for a two inch trashrack spacing and an approach velocity of 1.5 feet per second.
A stipulation that at least 1,000 cfs of water must always be allowed to spill over the dam will be included to regulate operation such that waters below the dam will receive necessary re-aeration to preserve existing aquatic habitats. The project will be operated as a “run of the river” facility and pose no effect to the U.S. Army Corps of Engineers (USACE) operation of the lock and dam, said the agency.
The powerhouse will be controlled with an automated system that would automatically start up, run, and shut down the turbines. The automated system would allow the USACE to modify hydroelectric operations instantaneously in response to emergencies related to lock operation or flood control.
An antidegradation assessment for this project had gone out for public notice in February 2014. The applicant presented a new turbine configuration on Feb. 19 of this year. The new proposal is to change the number of turbines from nine “small” turbines to four “large” turbines.
The length of the primary transmission line is proposed to be approximately 3,235.4 feet. The powerhouse transmission line will be supported on existing USACE structures for 2,070.1 feet, 837.2 feet will utilize state lands and 328.1 feet will be on private property.
The Illinois EPA public notice mentions a licensing process for this project at the Federal Energy Regulatory Commission. The latest filing in the case at FERC came on Aug. 12 from the company and said about the history of this process: “Northern Illinois Hydropower, LLC (NIH or Applicant) submitted an Application for Initial License (Application) for the proposed Dresden Island Hydroelectric Project (FERC No. 12626) (Project) on April 31, 2009. FERC issued a ‘Notice of Availability of Environmental Assessment’ on July 5, 2011. On September 30, 2014 the Applicant filed a revised Application to satisfy the requests of the resource agencies. The revision did not fully update the application, but provided relevant information to the revision.
“On November 5, 2014, FERC issued a Request for Additional Information (AIR) related to that filing. NIH filed a response to the AIR and a revised License Application on March 23, 2015. On June 12, 2015 FERC issued an AIR related to the revised Application. NIH herein responds to that AIR and provides the documentation requested by FERC.”
The revised license application filed with FERC in March said: “The proposed powerhouse would contain four 3.2-m diameter Kaplan turbines coupled to 2740 kW synchronous generators for an approximate combined maximum generating capacity of 10.96 MW at a design head of approximately 17 feet. Each unit would have a minimum hydraulic capacity of 455 cfs and a maximum hydraulic capacity of 2275 cfs for a combined maximum hydraulic capacity of 9100 cfs. The proposed powerhouse would have an estimated annual energy production of 58,500 MWh.
“The Applicant will control the project with an automated system that will automatically start up, run, and shut down the turbines. The automated control package will have overload, fault, and runaway speed protection. The system will allow the USACE to modify hydroelectric operations instantaneously in response to emergencies related to the lock operation or flood control. The Applicant proposes to operate the plant as run-of-river in a manner that does not interfere with or alter USACE operations or existing flow regimes.
“Currently no transmission lines exist at the Dresden Island Project. The Applicant proposes to install a transmission line from the proposed transformer switchyard adjacent to the powerhouse, approximately 0.5 mi to a Commonwealth Edison pole south of the navigation lock.”