Engineering Inc. - November/December 2010 - (Page 22)

MULTI-PROJECT FEATURE PROJECT: Holtwood Expansion Project, Holtwood, Pa. FIRM: L Kleinschmidt Associates, Pittsfield, Maine ocated in Holtwood, Pa., on the Susquehanna River, PPL Holtwood LLC’s 100-year-old hydroelectric station has a generating capacity of 108 megawatts (MW). As demand for hydroelectric power has grown, PPL has set about the difficult task of increasing the output of its century-old generator. Planning for the project began in 2004 when PPL tapped engineers in Kleinschmidt Associates’ Pittsfield, Maine, office to perform feasibility studies for an expansion that would increase the plant’s generating capacity by 25 MW, roughly enough renewable energy to power an additional 100,000 homes. Construction on the project, which benefitted from invest- ment tax credits as part of the American Recovery and Reinvestment Act, began in 2009 and is scheduled for completion in the first quarter of 2013. Before construction began, Kleinschmidt worked with the utility in 2004 and 2005 to determine the best approach for the project. Upon receiving the contract award, Kleinschmidt became responsible for designing all of the features of the expansion, including replacement of an upstream skimmer wall, replacement of existing spillway inflatable dam sections with pneumatic actuated steel gates, construction of a tunnel to extend a draft tube, numerous environmental remediations and enhancements, and the excavation of more than 1.5 million cubic yards of rock from the tailrace, forebay and adjacent areas. “The goal is to expand the hydroelectric generating plant and more than double its existing capacity, as well as to help American shad and other migratory fish adapt to changed water patterns in their annual migration from the Atlantic Ocean and Chesapeake Bay to the Susquehanna and its tributaries,” says Thomas Kahl, Kleinschmidt’s vice president of hydro engineering. The site posed many environmental challenges. Periods and types of construction, for example, had to be adapted to suit the shad’s migratory season. An active bald eagle nest on the site is continuously monitored to ensure the eaglets are not disturbed. “We designed and built an 80-foot tower and equipped it with a camera to keep watch,” says Kahl. There is also an endangered species of American holly onsite. “We are being guided by the Endangered Species Act and have solved the problem by adapting the design to leave as many existing trees untouched as possible; elsewhere, mitigation is being performed by relocating trees and even by beginning a nursery for future transplantation back onto the acreage,” Kahl says. All construction is designed to minimize interruption of the existing plant’s operations and to ensure the safety of the site, the coexisting wildlife and the people performing the work, he says. (above): Workers excavated more than 1.5 million cubic yards of rock as part of a massive expansion at the Holtwood LLC hydroelectric station in Pennsylvania. (below): The finished project along the Susquehanna River doubled the plant’s generating capacity. Thomas Kahl Electricity With an Environmental Conscience 22 ENGINEERING INC. NOvEMbER / DECEMbER 2010

Table of Contents for the Digital Edition of Engineering Inc. - November/December 2010

Engineering Inc. - November/December 2010
Contents
From ACEC to You
News and Notes
Market Watch
Legislative Action
Power Play
2010 Fall Conference Highlights
Ins and Outs
Re-energized
Business Insights
Young Professionals of the Year
Members in the News

Engineering Inc. - November/December 2010