Performance

Spotlight

Austin Energy: Pumping System Improvement Project 

Saves Energy and Improves Performance at a Power Plant

Project Summary

In March 2004, Austin Energy—the electric utility for the city of Austin, Texas—

completed an improvement project on the circulating water pumping system that 

serves a 405-MW steam turbine at its Decker Creek Generating Station. First, 

a pumping system assessment was performed in part by a U.S. Department of 

Energy (DOE) Qualifi ed Pumping System Assessment Tool (PSAT) Specialist from 

Flowserve Corporation; this assessment helped utility personnel create a project 

that would improve the systemʼs energy effi ciency and output capacity. It involved 

upgrading several of the pumpsʼ critical components as well as reconfi guring some 

equipment. When it was completed, the project greatly improved the pumping 

systemʼs effi ciency and performance. These improvements resulted in signifi cant 

energy savings and reduced maintenance requirements. 

Plant/Project Background

The Decker Creek Generating Station has two steam turbines and 200 MW of gas 

turbine peaking units. This project focused on the largest steam turbine, a 405-

MW power plant that has been serving the city of Austin, Texas, since 1978. Two 

1000-horsepower (hp) circulating water pumps deliver cooling water from a lake to 

equipment that condenses the steam coming from the turbine. Before the project, 

these pumps were unable to deliver the amount of cooling water required despite 

operating at full load. 

Both pumps were designed to have a combined fl ow rate of 236,000 gallons per 

minute (gpm), which was supposed to achieve a turbine back pressure (TBP) 

of no more than 3.5 inches. During routine, twice-yearly heat rate testing, plant 

personnel found that the cooling water fl ow was insuffi cient to achieve the rated 

steam fl ow, and the power plantʼs effi ciency was more than 5% below the design 

effi ciency level. The assessment revealed that the systemʼs actual fl ow rate when 

both pumps were running had degraded to 195,000 gpm, that pump effi ciencies 

were between 50% and 55%, and that the TBP at times increased to as high as 

4.1 inches of mercury absolute (HgA), or more than 17.5% above the design TBP. 

Furthermore, the pumps were vibrating severely, sump vortexes were frequent, and 

impeller surfaces were severely eroded. 

The project involved upgrading the circulating water pumps with new impellers, 

diffusers, shrouds, and shafts. In addition, the plant personnel and Flowserveʼs 

pump repair shop reconfi gured the suction bell, sections of the intake sump of both 

pumps, and the pumping station. Finally, they replaced the suction fl ow splitter 

below the pumps to better direct the incoming lake water.

Benefi ts 

• Saves $1.2 million annually

• Reduces annual energy 

consumption by 220,000 MMBtu

• Reduces maintenance costs

• Achieves 11-month simple payback

Industrial Technologies Program 

Proven Tools and Practices to 

Increase Industrial System Energy Effi ciency

Applications 

Circulating water pumping 

systems are needed for any 

application in which cooling 

water is required to maintain the 

temperature of a process. In this 

application, a power plant uses 

cooling water to condense steam. 

Proven Tools and Practices to 

Increase Industrial System Energy Effi ciency
BestPractices is part of the Industrial 

Technologies Program, and it supports 

the Industries of the Future strategy. 

This strategy helps the country’s 

most energy-intensive industries 

improve their competitiveness. 

BestPractices brings together emerging 

technologies and energy-management 

best practices to help companies 

begin improving energy efficiency, 

environmental performance, 

and productivity right now.

BestPractices emphasizes plant 

systems, where significant efficiency 

improvements and savings can be 

achieved. Industry gains easy access 

to near-term and long-term solutions 

for improving the performance of 

motor, steam, compressed air, and 

process heating systems. In addition, 

the Industrial Assessment Centers 

provide comprehensive industrial 

energy evaluations to small- and 

medium-size manufacturers.

A Strong Energy Portfolio 

for a Strong America

Energy efficiency and clean, renewable 

energy will mean a stronger economy, 

a cleaner environment, and greater 

energy independence for America. 

Working with a wide array of state, 

community, industry, and university 

partners, the U.S. Department 

of Energy’s Office of Energy Efficiency 

and Renewable Energy invests 

in a diverse portfolio of energy 

technologies.

FOR ADDITIONAL INFORMATION, 

PLEASE CONTACT:

EERE Information Center

1-877-EERE-INF

(1-877-337-3463)

www.eere.energy.gov

Visit our home page at

www.eere.energy.gov/industry

Industrial Technologies Program

Energy Efficiency and Renewable Energy

U.S. Department of Energy

Washington, DC 20585-0121

Results

These improvements to the plantʼs circulating water-pumping system resulted in an 

increase in the pumpsʼ combined flow rate to 11.5% above their design rating. This 

increase sharply reduced the need to operate both pumps concurrently to satisfy 

the plantʼs cooling water demand. Because of the reduction in the parasitic pump 

load and in the need for additional cooling water, the plantʼs efficiency increased, 

yielding annual energy savings of 220,000 MMBtu and energy and maintenance 

cost savings of $1.2 million per year. With total project costs of $1.1 million, the 

project had a simple payback of 11 months.

Lessons Learned

Circulating water-pumping systems should be checked periodically to ensure that 

they are operating satisfactorily. At the Decker Creek Generating Station, a kink at 

the low spot in the impulse line from the condenser to the vacuum manometer in 

the control room caused a water leg (trap), which prevented the vacuum manometer 

from providing accurate TBP readings. This, in turn, masked the performance of 

the system. Once the entire system was reviewed, including the pumpsʼ efficiencies, 

plant personnel were able to discover the suboptimal flow rate of the pumps, 

determine its cause, and devise an appropriate improvement strategy. 

After the project, tests showed that pump efficiency levels had risen to 85%. 

More importantly, the pumping system flow rate improved significantly. 

The pumps can now deliver more than 263,000 gpm, an 11.5% increase above 

the original design flow rate. There has also been a large reduction in vibrational 

amplitudes, from as high as 3.3 mils down to 0.2 mils, and a TBP improvement 

of about 3.2 inches HgA. These improvements allow the plant to operate at full 

capacity using only a single pump, and to do so much later into the summer than it 

did before the project began—saving both energy and money. The methods applied 

in this project can be implemented in power plants and at practically all industrial 

facilities that require water for process cooling.

Project Partners

Austin Energy Company

Austin, TX

Flowserve Corporation

Phillipsburg, NJ

Partner Profile

Alan Flory is a mechanical engineer and a PSAT Qualified Specialist who has been with Flowserve for 12 years. He has worked with 

Flowserve’s IT group to develop pump selection software and has 

authored technical papers on boiler feed water pumps. In his current 

role as Industry Director, he focuses on upgrading the efficiency and 

reliability of pumping systems for Flowserve’s industrial customers.

Qualified Specialists

Qualified Specialists are industry professionals who identify costcutting and efficiency opportunities in industrial plants. Experienced 

professionals who complete a qualification training workshop and exam 

for specific DOE-developed software tools receive special designations, 

and they can use these tools to help plants reduce costs, decrease 

maintenance and downtime, and improve productivity. The training 

recognizes and enhances a professional’s expertise in the use of DOE’s 

AIRMaster+ software tool, Pumping System Assessment Tool, Process 

Heating Assessment and Survey Tool, and Steam System Tools. For 

information, visit www.oit.doe.gov/bestpractices/software_tools.shtml.

Alan Flory

DOE/GO-102005-2083

June 2005