®

INSIDE THIS ISSUE:

18 BRINGING MILLER CREEK

BACK TO FULL PRODUCTION

26 NEW TOOL ALLOWS

ON-SITE GOVERNOR TESTING

46 HOW MARINE HYDROKINETICS

IS PROGRESSING

Stay Current

Powering UpADDING HYDRO TO AN EXISTING DAM

October 2014

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10 HYDRO REVIEW / October 2014 www.hydroworld.com

The U.S. Army Corps of Engineers (USACE)

broke ground on Mahoning Creek Dam, a

food control structure that also provides recreational

opportunities in the Allegheny River basin in western

Pennsylvania, in 1939. By 1941, the concrete dam

was fnished. The design included a conduit that

would allow the potential energy of water stored

behind the dam to be used to produce hydroelectric

power. However, the plans to develop hydropower

at this dam were postponed due to steel shortages

associated with the country’s accelerating mobiliza-

tion efforts for World War II.

Seventy-two years later, Enduring Hydro LLC,

a Maryland-based company, fulflled the vision of

those early engineers. In a public-private partnership

with the USACE’s Pittsburgh District and enabled

by the 2009 American Recovery and Reinvestment

Act and Pennsylvania Alternative and Clean Energy

Program, Enduring Hydro constructed a 6-MW

hydroelectric facility utilizing Mahoning Creek Dam.

The Mahoning Creek Hydroelectric Company

Project is located on Mahoning Creek in Armstrong

County, Pa. Mahoning Creek Dam is one of 16

facilities in the USACE’s Pittsburgh District used

to provide food protection to the lower Allegheny

River Valley and upper Ohio River. This concrete

gravity dam is 187 feet high and 926 feet long. The

hydro project includes a 50-foot-high intake structure

attached to the upstream face of the dam equipped

with a removable trashrack and a vertical slide gate. A

secondary penstock closure device, a butterfy valve,

is located in a concrete vault downstream from the

dam. A steel liner pipe was inserted into the existing

conduit through the dam. Water is conveyed from

the dam through a 1,090-foot-long, 10-foot-diameter

buried penstock to the powerhouse containing two

Francis turbines (4 MW and 2 MW) with two

vertical-shaft generating units.

The electricity produced is transferred to West

Penn Power at the nearest point of interconnec-

tion via an underground 1,200-foot-long 25-kV

line. A 10-year power purchase agreement was in

place before construction of the project began with

ground-disturbing activities on Jan. 31, 2013. Com-

mercial operations commenced on Dec. 26, 2013.

The Mahoning Creek project was designed to

Kristina M. Johnson is

chief executive offcer,

Mark Garner is managing

director/hydropower, and

John Collins is executive

vice president and director

of business development

with Enduring Hydro LLC.

John Strough is senior

project manager with

Hydro Consulting &

Maintenance Services Inc.

By Kristina M. Johnson,

E. Mark Garner, John R.

Collins and John Strough

More than 70 years in the making but less than a year in the execution, the 6-MW Mahoning Creek Hydroelectric Project, developed at an existing dam, is now providing clean, reliable power to residents in western Pennsylvania.

N e w D e v e l o p m e n t

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www.hydroworld.com October 2014 / HYDRO REVIEW 11

produce more than 20,000 MWh per year

for more than 50 years, which is enough

energy to power 1,800 homes with 100%

clean electricity. Furthermore, this hydro-

power facility will avoid 20,000 tons of C02,

20 tons of N0x, and 460 grams of mercury

emissions on an annual basis, equivalent to

taking 4,000 cars off the road or planting

1,000,000 fully grown trees with respect to

the reduction in greenhouse gas emissions.

In addition to the above-mentioned

environmental benefts, retroftting non-

powered dams creates well-paying, highly-

skilled crafts jobs, thereby economically

empowering local communities. The project

created more than 100 jobs utilizing local

labor in Armstrong County. The project

developer hired several Pennsylvania frms,

including Hanlon Electric in Monroeville,

Renick Brothers in Slippery Rock, and

Hydro Consulting and Maintenance Ser-

vices Inc. in York.

According to Oak Ridge National Labo-

ratory’s “Assessment of Energy Potential at

Non-Powered Dams in the United States,”

an April 2012 study, there are 45 non-

powered dams in the Commonwealth of

Pennsylvania that could collectively provide

hydropower capacity of 630 MW. From

our experience, if these 45 projects were

developed they potentially could create

more than 10,000 jobs, power 200,000

homes, and take the equivalent of 400,000

cars off the road.

Innovations in the plant design

The hydro project was designed by Mead

and Hunt of Madison, Wisc., under an

original contract with Advanced Hydro

Solutions (AHS) of Fairlawn, Ohio. Endur-

ing Hydro bought Mahoning Creek Hydro-

electric Company, the owner of the 50-year

Federal Energy Regulatory Commission

license, from AHS on July 31, 2012. We

worked closely with Mead & Hunt and

Kleinschmidt Associates of Pittsfield,

Maine, to obtain the Section 404 and 408

permits from the USACE and the 401

Water Quality Certifcate from the Com-

monwealth of Pennsylvania’s Department

of Environmental Protection (PADEP),

which needed to be in place before breaking

ground in January 2013.

During the construction process, an

intake structure on the upstream side of the

dam was installed and then sealed before the

concrete plug downstream was removed,

obviating the need for a cofferdam. A dam

liner pipe was inserted to connect with the

penstock. The project’s penstock, supplied

by Northwest Pipe Co. of Vancouver,

Wash., is 10 feet in diameter and extends

1,090 feet downstream from Mahoning

Creek Dam before bifurcating into two

smaller sections. The bifurcated piece is

located just before the penstock enters the

powerhouse. In total, 54 pieces of 20 feet

in length were placed and welded on site.

The buried penstock bifurcates into

two 110-foot-long sections, one 8-foot-

diameter section and one 6-foot-diameter

section. The hydro plant was designed

so that during low-fow periods, only the

2-MW unit, which can generate power

with a minimum fow of 120 cubic feet

per second (cfs), operates. During the

shoulder periods (fow between 350 and

500 cfs), we expect the 4-MW unit, which

requires a minimum fow of 350 cfs, to

The liner pipe was installed through Mahoning Creek Dam and the opening in the bulkhead plate was cut to

ensure optimal transmission of water stored in the reservoir to the penstock when the roller gate is open.

The Mahoning Creek Hydroelectric Company powerhouse contains a control room and two turbine-generator

units. The 4-MW generator is shown in the foreground and the 2-MW generator is visible in the background.

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12 HYDRO REVIEW / October 2014 www.hydroworld.com

operate. Finally, during the periods when water fows exceed

500 cfs, both the 2-MW and 4-MW units will produce power.

Environmental considerations in the FERC license and the

adaptive management plan with the USACE require a minimum

bypass fow of 60, 40 and 30 cfs, during the low-, shoulder and

high-fow periods, respectively.

All turbine components including the draft tubes, spiral cases,

runner, distributor and shut-off valves were supplied by China

Harbour Engineering Company Ltd. (CHEC) No. 9 of Beijing,

China. The generators, switchgear, and control system were sup-

plied by Hyundai Ideal of Mansfeld, Ohio.

The powerhouse’s switchgear and controls are sensitive, com-

plex technologies. To mitigate the technological risk of installing

separate interfaces in the powerhouse, Enduring Hydro worked

with PCX of Clayton, N.C., to skid-mount the instrumentation

controls prior to installation. PCX integrated various technologies

in their factory and their expert team assembled a comprehensive

skid that was installed in one piece in the powerhouse.

The dam liner pipe was installed and the opening in the bulkhead

plate was cut, ensuring optimal transmission of water stored in

the reservoir to the penstock when the roller gate, supplied by

Steel-Fab of Fitchburg, Mass., is open. The valve vault built just

downstream from the dam liner pipe includes the butterfy valve,

supplied by Henry Pratt Co. of Aurora, Ill. This construction

process required detailed planning and coordination between the

Enduring Hydro team, FERC, and the USACE.

Innovations in the permitting, approval

and construction process

To keep the project on schedule, the Enduring Hydro team worked

diligently to obtain the permits and approvals required from the

The project’s 10-foot-diameter penstock extends 1,090 feet downstream from

Mahoning Creek Dam before bifurcating into two smaller sections just before

the penstock enters the powerhouse.

1410hr_12 12 9/29/14 4:24 PM

ROLLER GATESMahoning Creek Project

Steel-Fab designed and manufactured

a 9 ft. wide x 13 ft. tall roller gate for

The Ruhlin Company for the construction

of Enduring Hydro, LLC's six-megawatt

hydroelectric facility located on the

Mahoning Creek Dam.

■ Jet Flow Gates

■ Bonneted Gates

■ Miter Gates

■ Gate Operating Systems

■ Fixed Cone Valves

430 Crawford St., Fitchburg, MA 01420 USATel 978-345-1112 ■ Fax 978-343-7925

www.steel-fab-inc.com

■ Crest Gates

■ Roller Gates

■ Slide Gates

■ Tainter Gates

■ Floating Bulkheads

The Mahoning Creek Project was designed

by Mead and Hunt, Inc.,whose founder was

involved in the development of the Hoover

Dam. The concrete gravity dam, constructed

in 1941 by the U.S. Army Corps of Engineers,

with a height of 162 feet and a length of

926 feet, impounds Mahoning Creek,

a tributary of the Allegheny River, and

provides flood protection for the lower

Allegheny River Valley and the upper

Ohio River.

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14 HYDRO REVIEW / October 2014 www.hydroworld.com

various stakeholders and governing agencies,

including the USACE (Pittsburgh District,

Great Lakes and Ohio River Division, and

headquarters), FERC, PADEP and Pennsyl-

vania Fish and Boat Commission (PAFBC).

To comply with the various regulatory

processes and approvals and maintain

the project’s tight construction schedule,

Enduring Hydro planned the construction

activities in stages. Each stage corresponded

to the receipt of the regulatory approval

over a four month period of time, as shown

in Table 1 on page 16.

The Enduring Hydro team credits the

strong public-private partnership with the

USACE, FERC, PADEP, and PAFBC for

the successful and timely completion of

the project.

Challenges

Enduring Hydro faced several major chal-

lenges while completing the project. First

and foremost was obtaining the necessary

permits and notices to proceed in a timely

manner. Our consultants at Mead & Hunt

and Kleinschmidt Associates were invalu-

able in helping us anticipate and address the

concerns of these key regulatory partners

to obtain all the approvals. This was the

frst greenfeld hydroelectric project built

in Pennsylvania in more than 20 years and

therefore the frst plant built at a USACE

dam post-Hurricane Katrina with the new

408 permit requirement.

The second major challenge was the

narrow site condition. The access point,

from the McRae Furnace Bridge across

a runoff stream from Mahoning Creek to

the dam, was often referred to as a “bowl-

ing alley,” allowing for a single ingress and

egress. This required effcient construction

management in order to maintain the proj-

ect’s tight construction schedule.

A third challenge involved assessing the

geotechnical conditions where the penstock

would be buried, prior to receiving the

notice to proceed on ground-disturbing

activities. Once we had full access to the

site, we discovered that the solid rock

foundation was deeper than originally

anticipated. While the lack of solid rock

led to less rock excavation, it did require

proper flling material to be sourced and

installed to support the penstock. The lack

of rock also required the installation of rock

anchors for the stilling basin wall between

the penstock and the bank of the stilling

basin just downstream of the dam.

Results

As a result of the teamwork and collabora-

tion between Enduring Hydro; its suppli-

ers and vendors; and the USACE, FERC,

PADEP and PAFBC, the project began

commercial operations on Dec. 26, 2013.

Achieving commercial operations prior to

Jan. 1, 2014, allowed the project to qualify

for the 1603 cash-back grant from the U.S.

Treasury. Since commencing commercial

operations, the project has produced about

12,000 MWh of electricity during the frst

half of 2014. We estimate the project will

generate about 20,000 MWh in its frst

year of operation.

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16 HYDRO REVIEW / October 2014 www.hydroworld.com

Effective Nov. 14, 2013, Mahoning

Creek Hydroelectric Project was certifed as

a “Low Impact” facility by the Low Impact

Hydropower Institute (LIHI) Certifcation

Program, an independent non-proft orga-

nization. LIHI certifcation is granted to

projects that comply with LIHI’s rigorous

review process and meet its goals of achiev-

ing required clean energy benefts while

meeting strict environmental standards.

Acknowledgments

The Mahoning Creek Dam powerhouse

is named for E. Mark Garner, a long-time

champion of hydropower throughout his 25

years in the industry. As an engineer, chief

executive offcer, and business leader, he

has advocated for innovation and provided

value engineering to improve hydropower

into the 20th and 21st centuries. Through

his leadership, Mahoning Creek Dam pro-

duced electricity in 2013, carrying out the

vision of the original dam builders from

1939. We would also like to acknowledge

the contributions of David Nammour and

David Fox, project engineers; Jennifer

Mesirow, controller; Ginger Lew, managing

director; Marcus Switzer, compliance and

regulatory; Andrew Longenecker, senior

associate; and Smitha Ramakrishna, analyst,

all part of the Enduring Hydro team. ■

Table 1: Timeline for Acquiring Regulatory Approvals and Permits

Date Event Entity Requirement

7/31/2012Mahoning Creek Hydroelectric purchased from Advanced Hydro Solutions

Enduring Hydro

1/31/2013Permission granted for ground clearing activities at the access road

FERC

2/19/2013Section 401 permit issued — ground clear-ing begins

Pennsylvania Depart-ment of Environmental

Protection (PADEP)

2/26/2013 All private easements secured Enduring Hydro

3/7/2013 Limited Power Permit issued PADEP

3/8/2013 Section 408 and Section 404 permits issuedU.S. Army Corps of Engineers (USACE)

3/12/2013Permission granted to start work on the intake structure, powerhouse and further geotechnical investigation

FERC

3/14/2013 Financing plan approved FERC

3/22/2013

Permission granted to perform land-disturbing activities on USACE property, including site mobilization, access road refurbishment, and powerhouse and tailrace ground clearing

USACE

5/2/2013Final design review meeting with indepen-dent external peer review (IEPR) team at the site

FERC

5/8/2013Limited permission granted to start work on penstock and valve vault

FERC

5/10/2013

Dive plan approved and permission granted to proceed with construction of all activities under "dam" as shown in the "Preliminary Partial Project Construction Schedule"

USACE

5/31/2013

Permission granted to proceed with the rest of the construction activities under "penstock," including work at the intake structure

USACE

8/13/2013IEPR meets at the site to inspect the existing conduit through the dam prior to placement of penstock

FERC

11/13/2013IEPR meets at the site to inspect that con-struction is in compliance with approved plans and specifcations

FERC

12/16/2013IEPR meets at the site for fnal walk-through and inspection prior to plant water-up and commissioning

FERC

12/17/2013Memorandum of agreement signed estab-lishing operational protocols between MCHC and USACE

USACE

12/26/2013Mahoning Creek Hydroelectric Project Commissioned

Enduring Hydro

About Enduring Hydro

The Enduring Hydro team is led

by former U.S. Under Secretary of

Energy Dr. Kristina Johnson, former

chief executive offcer of Voith Hydro

Mark Garner, former chief fnance

offcer of Constellation Energy John

Collins, and former senior counselor to

the White House National Economic

Council Ginger Lew. Working with our

senior associate Andrew Longenecker,

controller Jennifer Mesirow, project

engineers David Nammour and David

Fox and chief of staff Marcus Swit-

zer, this team brought on-line the frst

non-powered dam in Pennsylvania

in more than 20 years. Our team is

committed to helping clean our air

by replacing carbon-based electricity

with environmentally responsible, run-

of-river hydropower at greenfeld and

brownfeld sites.

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