Fall 2001

ISSUE FOCUS: 

Alternative Power Sources

T OF ENERGY

DEPARTMEN

U

E

NITED STAT S OFA

ERICA

M

A BestPractices PUBLICATION ON IMPROVING INDUSTRIAL ENERGY EFFICIENCY

OFFICE OF INDUSTRIAL 

TECHNOLOGIES • 

U.S. DEPARTMENT OF ENERGY 

www.oit.doe.gov 

www.oit.doe.gov/bestpractices

On August 27-29, 2001, OIT and the State

of Utah hosted the Utah 2001 Showcase at

the Sheraton City Center in Salt Lake City.

The event featured several advanced technologies and best practices in three of the

most energy-intensive industries: aluminum, mining, and petroleum refining. 

The showcase gave six manufacturing

plants the opportunity to demonstrate the

progress they’ve made toward improving

efficiency, enhancing competitiveness, and

reducing pollution. At the same time, the

showcase demonstrated to about 400

attendees how a strategic partnership

between OIT, the State of Utah, and industry has led to this progress—and how similar alliances can help industries across the

nation continue to grow and prosper.

Plants Highlight Improvements 

Critical factors, such as the rapid pace of

technology change, rising energy costs, and

competitive pressures led companies to

take part in innovative partnerships that

address these challenges. “The Utah Showcase brought focus to the synergy of partnerships with OIT and others,” comments

Jim Bollenbacher, Vice President of Environment, Health, and Safety for Alcoa’s North

American Extrusion unit. Alcoa, Kennecott

Utah Copper, Magnesium Corporation of

America (Magcorp), Chevron, Flying J, and

Silver Eagle opened their doors to show

what they have accomplished. 

Aluminum

At the Alcoa Extrusion facility in Spanish Fork, visitors learned about energy efficiency projects, such as a compressed air

system upgrade, which could yield energy

savings of 1,500 million British thermal

units (Btu) per year. As part of Alcoa’s corporate energy conservation program, this

facility is also evaluating a cooling tower

control system, improved dross recovery,

regeneration burners, alternative combustion methods, a vertical flotation melter,

and advanced sensors.

Mining

Kennecott Utah Copper’s showcase

gave visitors a look at the immense Bingham mine and the Copperton Concentrator,

where copper is recovered from the ore.

Through a series of upgrades to its smelting

operation, the company saves about 55%

in energy use and has also achieved substantial emissions reductions. 

Meanwhile, magnesium producer Magcorp showcased an upgraded electrolysis system that has reduced electric energy use by

OIT/Utah Showcase Industrial Energy Efficiency

Wind power, see page 7.

IN THIS ISSUE

OIT/Utah Showcase . . . . . . . . . . . . . . . . 1

Increased Efficiency through 

Waste Heat Recovery . . . . . . . . . . . . . . 3

Industrial Manufacturers Help 

Develop Green Power Market . . . . . . . . 5

Black Liquor Gasification . . . . . . . . . . . 6

Power of the Wind . . . . . . . . . . . . . . . . . 7

Performance Optimization Tips—

Measuring the Heart Rate of Motor

Systems: Electric Current . . . . . . . . . . . . 8

OIT Developing Portfolio of

Plant-Wide Assessments . . . . . . . . . . . . 10

Assessment of Compressed 

Air Market . . . . . . . . . . . . . . . . . . . . . . . . 10

Energy Solutions for California . . . . . . 11

Letters to the Editor . . . . . . . . . . . . . . . . 11

EM Extra . . . . . . . . . . . . . . . . . . . . . . . . . 11

Coming Events . . . . . . . . . . . . . . . . . . . . 12

(continued on page 2) ©

INSERT:

Distributed Energy/Combined Heat and Power

Plant tours were a highlight of the Utah 2001 Showcase, where six companies

demonstrated advanced technologies and best practices in the aluminum, mining,

and petroleum refining industries.
2 Energy Matters, Fall 2001

ENERGY MATTERS

is published quarterly by the 

U.S. Department of Energy’s

(DOE) Office of Industrial 

Technologies. 

Information contained in the

newsletter can be reproduced

without permission provided due

acknowledgement is given (the

U.S. Department of Energy’s 

Energy Matters newsletter) and 

a copy of the publication is 

supplied to the editor.

■

EDITORIAL BOARD

Rob Boteler, representing

National Electrical Manufacturers

Association

Lynda Butek, representing 

Electrical Apparatus Service 

Association

Keith Davidson, Energy Nexus

Group

Glenn Hahn, Spirax Sarco

Aimee McKane, representing the

Compressed Air Challenge®

Bill Stafford, Technical Association

of the Pulp and Paper Industry

Arvind Thekdi, CSGI, Inc.

Chuck Whelan, DuPont 

■

DOE STAFF

Chris Cockrill, BestPractices,

Motors

David Crouch, BestPractices

Communications 

Bob Gemmer, BestPractices,

Process Heating

Fred Hart, BestPractices, Steam 

Theo Johnson, BestPractices 

Program Manager

■

COMMENTS? 

Contact: 

Michelle Mallory, 

Energy Matters Editor, at 

303-275-3627, or e-mail 

michelle_sosa-mallory@nrel.gov

1617 Cole Blvd., MS 1609

Golden, CO 80401

For address/subscription changes,

please contact the editor.

For new subscriptions, go to

www.oit.doe.gov/

bestpractices/energymatters/

energy_matters.shtml

30% and has also reduced maintenance and

labor costs. Magcorp’s combined heat and

power (CHP) system exceeds 75% overall

thermal efficiency and the company is evaluating an upgrade for even better efficiency.

(See page 1 of this issue’s special supplement

for more on Magcorp’s CHP system.) 

Petroleum Refining

Chevron provided an overview of the

plant’s furnace efficiency and steam system

management efforts and an air system capital project. In addition, Chevron highlighted its gas combustion research project.

Flying J featured several new technologies for saving energy and improving manufacturing efficiency, among them a reverse

osmosis unit that will save the company an

estimated $200,000 per year. Others

include advanced process controls, variable

frequency drives for highly throttled pumps,

a new compact cracking process, and a

plant-wide energy tracking system.

At Silver Eagle, the focus was on new

technology in reforming operations and an

efficient waste heat boiler system. Visitors

learned how Silver Eagle has implemented

recommendations from DOE assessments

throughout the plant. 

To learn more about the participating

companies’ projects, see the BestPractices

case studies on Energy Matters Extra at

www.oit.doe.gov/bestpractices/energymatters/emextra. 

An Exchange of Ideas 

Throughout the showcase, participants

exchanged ideas with others who are

focused on industrial efficiency. In the

exhibit hall, more than 40 exhibitors demonstrated advanced technologies and practices.

In addition, industry associations, the Utah

Energy Office, and DOE staff offered information about partnerships, industry programs, and projects that are ready for plant

floor application. During breakout sessions,

presenters led discussions on research, plant

technologies, business issues, and state initiatives that affect the showcase industries.

Keynote speaker Senator Orrin Hatch

(R-Utah) addressed the importance of

Utah’s industrial sector to the state and the

nation. He noted the value of OIT’s partnerships with states and acknowledged

that the showcase format hastens industry’s

understanding of new technologies.

During a congressional forum, Utah’s

three representatives, James Hanson, Chris

Cannon, and James Matheson, heard testimony from three panels representing government, industry, and industry associations.

Among the panelists was Denise Swink,

OIT’s Deputy Assistant Secretary, who

explained that through the Industries of the

Future strategy, OIT helps accelerate new

technology application, increases productivity, and helps save energy. 

Showcase cosponsors were OIT, the

State of Utah, the University of Utah, Alcoa,

Kennecott, Magcorp, Chevron, Flying J, and

Silver Eagle.

Take Part in a Showcase 

Learn more about the benefits of hosting a showcase on the BestPractices Web

Site at www.oit.doe.gov/bestpractices/

pdfs/showcase.pdf. Watch Energy Matters

or visit the BestPractices Web site at

www.oit.doe.gov/bestpractices for details

about upcoming OIT showcases. ●

Utah Showcase

continued from page 1

A vertical flotation melter demonstration

was part of Alcoa’s plant tour.

Industry leaders address Utah congressional representatives at a forum.

Photo courtesy of Alcoa/PIX 10233

Photo courtesy of Rolf Butters
Energy Matters, Fall 2001 3

By Richard L. Bennett, President, Janus

Technology Group Inc., Rockford, IL

Many industrial heating processes generate

large amounts of waste energy that simply

pass out the stacks and into the atmosphere. When energy is abundant and

cheap, no one seems to notice, but when

supplies get pinched and prices climb,

people begin to realize just how much of

their fuel dollar goes sailing into the blue.

Techniques for Heat Recovery

Stack exhaust losses are part of all fuelfired processes, and they increase with the

exhaust temperature and the amount of

excess air the exhaust contains. At stack

gas temperatures greater than 1,000°F, the

heat that is carried away is likely to be the

single biggest loss in the process. Above

1,800°F, stack losses will consume at least

50% of the total fuel input to the process.

Waste heat recovery offers a great opportunity to put some of this energy to work, 

reducing energy consumption and emissions and increasing productivity. There

are several techniques for heat recovery, all

based on intercepting the waste gases

before they leave the process, extracting

some of the heat they contain, and recycling that heat.

Direct heat recovery to the product.

This is the most efficient method. It takes

advantage of the fact that even in the highest temperature processes, the product or

charge enters the process at ambient temperature. If exhaust gases leaving the high

temperature portion of the process can be

brought into contact with a relatively cool

incoming load, energy will be transferred

to the load, preheating it and reducing the

energy that finally escapes with the

exhaust.

More often, heat is transferred to a surrogate medium, like combustion air to the

burner system. This reduces the amount of

purchased fuel required to sustain the

process. Figure 1 shows how preheating

combustion air affects available heat,

which is the thermal efficiency of the combustion process itself.

(continued on page 4) ©

Increased Efficiency through Waste Heat Recovery from Process Heating Systems

Figure 1. Effects of preheating combustion air on available heat. 

1000 1200 1400 1600 1800 2200 2400 2600 2800 2000 3000

80

60

40

20

10

30

50

70

90

Exhaust Gas Temperature, °F

(Btu = British thermal unit, cu ft = cubic feet, sp gr = specific gravity)

Percent Available Heat

Fuel: Birmingham Natural Gas (1002 Btu/cu ft, 0.6 sp gr)

0

100

100% (11.0%)

150% (13.1%)

200% (14.4%)

250% (15.4%)

10% (2.1%)

25% (4.5%)

50% (7.4%)

0% (0%) Excess air (02)

800°F

600°F

400°F

1400°F

1000°F

1200°F

1600°F

1800°F

2000°F Preheat

Preheated Air Curves Based on 10% Excess Air (2.1% O2)

ABOVE 1,800°F, STACK LOSSES WILL

CONSUME AT LEAST 50% OF THE TOTAL

FUEL INPUT TO THE PROCESS. WASTE

HEAT RECOVERY OFFERS A GREAT

OPPORTUNITY TO PUT SOME OF THIS

ENERGY TO WORK, REDUCING ENERGY

CONSUMPTION AND EMISSIONS AND

INCREASING PRODUCTIVITY.
4 Energy Matters, Fall 2001

Recuperators. A Recuperator (Figure 2)

is a gas-to-gas heat exchanger placed on

the stack of the furnace. There are numerous designs, but all rely on tubes or plates

to transfer heat from the outgoing exhaust

gas to the incoming combustion air, while

keeping the two streams from mixing. They

are the most widely used heat recovery

devices.

Regenerators. These are essentially

rechargeable storage batteries for heat. A

regenerator is an insulated container filled

with metal or ceramic shapes capable of

absorbing and storing relatively large

amounts of thermal energy. During part of

the operating cycle, process exhaust gases

flow through the regenerator, heating the

storage medium. After a while, the medium

becomes fully charged, so the exhaust flow

is shut off and cold combustion air is

admitted to the unit. As it passes through,

the air extracts heat from the storage

medium, increasing in temperature before

it enters the burners. Eventually, the heat

stored in the medium is drawn down to the

point where it is necessary to recharge the

regenerator. At that point, the combustion

airflow is shut off and the exhaust gases

return to the unit. This cycle repeats as

long as the process continues to operate.

Obviously, if the process is to operate

without interruption, at least two regenerators (and their associated burners) are

required—one to provide energy to the

combustion air while the other is recharging. It is much like a using a cordless

power tool—to use it continuously, you

must have at least two batteries to swap

out between the tool and the recharger.

The fundamental difference between

recuperators and regenerators is the way

they keep the exhaust gases and combustion air from cross-contaminating each

other. Recuperators separate the gas

streams with a physical barrier so they can

operate continuously. Regenerators operate

intermittently, keeping the streams separated by time.

Waste Heat Boilers. Here is an option

for plants that require a source of steam or

hot water. They are similar to conventional

boilers with one exception—they are heated

by the exhaust gas stream from a process

furnace instead of their own burners. 

Making the Choice

How do you decide which recovery

technique is right for your operation? In

some instances, more than one might fill

the bill, but here are some basic points that

factor into the selection process.

■ Direct heat recovery to the product has

the highest potential efficiency, because

it doesn’t require any “carrier” to return

the energy to the product. However, it

does require a furnace or oven configuration that permits routing the stream of

exhaust gases counterflow to incoming

product or materials. This usually rules

out most batch-type heating equipment.

■ Recuperators are available in the widest

range of sizes, configurations, and temperature ranges, and they don’t require

elaborate combustion control systems.

However, they must be protected

against overheating damage on hightemperature processes and may not be

suitable for some corrosive or dirty

exhaust gases.

■ Regenerators can operate at temperatures beyond the range of recuperators

and at higher efficiency ratings. They

are highly resistant to corrosion and

fouling, but because of their back-andforth switching, they require more complex, expensive flow control systems

than recuperators do.

■ Waste heat boilers may be the answer

for plants seeking more steam capacity,

but keep in mind the boiler generates

steam only when the process is running.

Where this is a concern, boilers with

auxiliary burners may be the answer. ●

Contact Richard Bennett by e-mail at

janustech@compuserve.com, or by phone

at 815-282-8044.

Waste Heat Recovery

continued from page 3

Figure 2. Recuperators transfer heat from outgoing gas to incoming combustion air without

allowing streams to mix. 

Preheated

combustion air

Exhaust gases

Recuperator

Furnace

Burner
Energy Matters, Fall 2001 5

Some industrial operations not only work

to improve their bottom lines and increase

energy efficiency now, but also look ahead

to using clean and renewable (or “green”)

sources of power, such as wind, solar,

landfill gas, and fuel cells. Among the

companies exploring these possibilities are

Cargill Dow LLC, Alcoa Inc., and DuPont.

Working with seven other companies

within the Green Power Market Development Group (the Group), they are developing strategies to reduce green power costs,

reduce market barriers, and help articulate

the business case for green energy use. 

Other member companies of the Group are

General Motors, IBM, Delphi Automotive,

Interface, Johnson & Johnson, Pitney

Bowes, and Kinko’s.

The Group, which is organized by the

World Resources Institute and Business for

Social Responsibility, acknowledges that

green power has substantial challenges to

overcome. As corporations work to optimize shareholder value, energy purchases

are often made on the basis of price alone.

However, not all of green power’s attributes

have monetary value, and there are some

good business reasons for purchasing green 

power, according to the Group, which says

that green power purchases can:

■ Protect against volatile fluctuations in

fossil fuel prices by providing an alternative to traditional power sources 

■ Provide financial value from avoided

emissions

■ Help corporations build leadership and

trust in the public eye, while differentiating themselves from the competition.

One of the Group’s goals is to work

toward a sustainable energy future. Similarly, OIT and BestPractices are facilitating

a sustainable U.S. industry by helping

manufacturers boost energy efficiency and

improve productivity. Learn more by logging on to the OIT Web site at www.oit.

doe.gov/ and the BestPractices Web site at

www.oit.doe.gov/bestpractices/. To learn

more about the Green Power Market

Development Group, log on to www.

thegreenpowergroup.org. ●

Industrial Manufacturers Help Develop Green Power Market

Landfill gas, solar

photovoltaics,

and wind power

are examples of

“green” energy

sources. 

Jeffrey Kolstad, chief scientist with Cargill Dow, represents the company in the Green Power Market Development Group. Cargill Dow uses annually renewable

resources, such as corn, to produce its polylactide polymer, developed in partnership with DOE. These resins

can be used as packaging materials or fibers for textiles,

carpeting, and nonwoven applications. To reduce

energy-related emissions generated in the polymer production process, Cargill Dow is working with the local

utility to buy energy generated from wind or landfill gas.

According to Kolstad, “Cargill Dow is committed to

reducing the environmental footprint of its polylactide

polymer. Using green power will enable further reductions in fossil fuel use and greenhouse gas emissions,

leading to a more sustainable future.” 

Jeff Kolstad, Chief Scientist,

Cargill Dow LLC, is the

company’s representative in

the Green Power Marketing

Development Group.

Ray Bleez, NREL/PIX 03890

Sacramento Municipal Utility District/PIX 01026

Warren Gretz, NREL/PIX 00043
6 Energy Matters, Fall 2001

Georgia-Pacific (G-P) and OIT have

teamed up to study and demonstrate black

liquor gasification, which is expected to

reduce air emissions by 90%, reduce operating costs, and increase energy efficiency

at the G-P containerboard mill in Big

Island, Virginia. It will be the first full-scale

black liquor gasification system used in the

commercial pulp and paper industry. G-P

and DOE will share the project cost of

approximately $85 million.

The system will replace two 50-year-old

smelters and will provide the entire chemical recovery capacity for the G-P mill. It

has potential for industry-wide applications

to replace Tomlinson recovery boilers,

which are the energy-intensive industry

standard. The process is suitable for all

pulping processes—carbonate, kraft, sulfite, nonwood, and others. Although the

technology initially requires a higher capital investment, it will provide capital

returns from reduced energy demands and

help the forest products industry meet

increasingly stringent Environmental Protection Agency (EPA) regulations. 

Promising New Technology

Black liquor is a spent product of the

chemical pulping/digesting process and a

source of energy for the papermaking industry. Black liquor gasification, the conversion

of leftover black liquor into a clean-burning

fuel for use in burners, boilers, and gas turbines, is a promising new technology for

reducing air emissions and increasing

energy efficiency in the pulping process.

The G-P project will employ a reactor in

which tubes, heated by pulses of fired gas,

are immersed in a mixture of sodium carbonate and spent black liquor. The pulsing

enhances a heat exchange between the

tubes and the mixture, which promotes the

chemical reactions that produce the fuel.

This process will treat all of the 400,000

pounds of black liquor solids that the mill

produces each day.

The process differs from other technologies because it does not require partial oxidation of the liquor inside the gasifier. Its

lower temperature allows the gasifier to

convert black liquor organic material to

gas at temperatures well below those

required for smelt formation, eliminating

the danger of smelt-water explosions in the

recovery boiler. This equipment will maximize the recovery of energy and chemicals

while producing a medium Btu fuel gas

(200 to 300 Btu/scf [standard cubic feet]).

Demonstration Phases 

The project is being conducted in two

phases. Phase I focuses on validating the

process design and solving any technology

gaps. Phase II will focus on completing the

engineering and construction and functional operation of the new system. 

Black Liquor Gasification Expected to Yield Energy, Environmental, and Economic Benefits

BENEFITS

■ Reduces NOX, SO2, CO, VOC, and

particulate emissions

■ Expected air emission reduction 

of 90%

■ Replaces existing smelters, eliminating threat of smelt-water explosions

■ Reduces use of nonrenewable 

(fossil) fuels

■ Increases energy efficiency

■ Decreases capital and operating

costs

■ Provides hydrogen-rich, cleanburning fuel

This figure depicts the black liquor gasification process to be implemented at Georgia-Pacific’s Big Island, Virginia, containerboard mill.

Black

liquor

Process

condensate

Black

liquor

Process

condensate

Bed

solids

Eductor Eductor

Reformer

boiler

Bed

solids

Dregs

BFW

Superheater

Green liquor

filter

Green liquor

(Na2CO3+Na2S)

to effluent

Superheated

steam to mill

Saturated

steam to mill

SO2

scrubber

Flare Stack

Gas

cooler

HRSG 2

Venturi 2

HRSG 1

Reformer 1 Reformer 2

Venturi 1

BFW

BFW Pulsed heater cooling circuit

omitted from this unit for clarity

Green liquor

(Na2CO3) to mill

(continued on page 10) ©
Energy Matters, Fall 2001 7

By Lynda Butek, representing the Electric

Apparatus Service Association, Colton, CA,

with guest editors Robert Thresher and

Kathleen O’Dell, National Wind Technology Center, National Renewable Energy

Laboratory, Golden, CO 

For centuries, man has harnessed the

power of the wind and put it to work.

Throughout Europe, Asia, and the Americas, farmers used wind power to pump

water and mill grains as far back as 300

B.C. The first turbines were developed in

Denmark in the 1890s, and by 1900, small

wind systems were generating direct current power for many rural homes and farms

in the United States. With the advent of

rural electric co-ops in the 1930s, small

wind turbines were no longer used to generate electricity; however, faced with the

ever-increasing cost of electric power,

today we are again turning to the power of

the wind to generate electricity for our

homes and businesses. 

Most states have enough wind to power

wind turbines, and 37 states have wind

resources that would support utility-scale

wind power plants. The wind resource in

the Great Plains, if properly developed,

could supply a significant portion of this

country’s electricity needs. With today’s

wind turbine technology, the United States

could supply 20% of its electricity needs

from wind alone, and with cost-effective

storage, wind could supply a much higher

percentage.

Modern Wind Turbines

Today’s wind turbines come in a variety

of sizes and power ratings. Small turbines

rated at 100 kilowatts (kW) and less can be

used in applications such as supplementing power supplies for single-family homes

and small businesses, water pumping, or

communications. Large, utility-scale turbines rated as high as 2 megawatts (MW)

are commonly grouped to form “wind

farms” or wind power plants that are connected to the utility grid to provide power

for hundreds of homes. A single 750-kW

turbine can provide enough electricity to

power approximately 250 average homes. 

Like the windmills of old, modern wind

turbines are mounted on tall towers to take

advantage of the best wind resources. Utility-scale turbines are mounted on towers up

to 200 feet high. Most of the turbines used

today look much like a child’s whirligig with

two or more (commonly three) large propeller-like blades mounted on a shaft to form

a rotor. The blades act much like airplane

wings. When the wind blows, a pocket of

low-pressure air forms on the downwind

side of the blade pulling the blade toward

it, causing lift. This lift force causes the

rotor to spin, which turns the shaft that

spins a generator to produce electricity.

In addition, wind turbines contain a

speed control system or brake. Although

wind is a natural part of our environment,

too much of a good thing (high gusting or

turbulent winds) can cause runaway generators that can overload and overheat if they

are not controlled or braked. The margin of

error between a full-loaded machine and

one that is dangerously overloaded can be

as little as 10%. Even though controls

cause a loss of overall efficiency, they are

necessary for safe operation of the units.

The obvious advantages of wind energy

are that the fuel is free, renewable, and

clean. Unlike conventional power plants,

wind plants emit no pollutants or greenhouse gases. According to a study conducted by the University of California at

Irvine, every 500 MW of wind generating

capacity can reduce emissions of carbon

dioxide, the leading greenhouse gas, by

more than half a million tons annually, 

sulfur dioxide by 637 tons, nitrogen oxides

by 1,496 tons, and particulate matter by 

17 tons. 

Barriers to Wind Power

Although wind energy was the fastest

growing energy technology during the

1990s, before it can be developed to its

full potential, researchers must find ways to

overcome some barriers. One of those 

barriers is the cost of wind energy production. In 1980, wind energy cost as much as

30 cents per kilowatt-hour (kWh) to 

produce. Joint research by DOE and members of industry has helped decrease that

cost by more than 80% to 4 cents per

kWh. To compete with conventional fuels,

the cost must be lowered further. Industry

members expect to reduce the cost of production an additional 30% with continued

research and the introduction of more

advanced, efficient turbine designs.

Another barrier to wind energy development is that wind is a fluctuating resource.

When the wind blows, it produces electricity. When the wind stops, that production

stops. This creates an intermittent energy

supply that may be difficult to integrate

into the utility grids. In addition, good

wind resources are often located in remote

locations far from major population centers

and transmission lines. By studying the

nation’s wind resources, its characterization, wind forecasting, the nature of current wind farms, and their impacts on the

utility grids, researchers are identifying the

best areas for development and demonstrating how wind energy can be integrated

into the generation mix. 

Several environmental groups have

voiced concerns about the impacts wind

turbines may have on avian populations,

especially the raptor populations. In

response to their concerns, DOE has

worked with industry members to conduct

studies on how birds interact with wind

turbines. Their studies show that with

proper wind farm siting, impacts on avian

populations can be greatly reduced. 

Despite the barriers facing the wind

energy industry today, wind energy’s

potential to meet this nation’s growing

electricity needs remains immense. With

continued research and development, barriers to wind energy development will be

removed, allowing the technology to

become a major player in the energy

industry so that it can help stabilize energy

supplies and pave the way to a cleaner

energy future. 

To learn more about wind technology

research, its potential, and current applications, please visit the National Wind Technology Center Web site at www.nrel.gov/

wind, or DOE’s Wind Energy Program Web

site at www.eren.doe.gov/wind. ●

The Power of the Wind 
8 Energy Matters, Fall 2001

Performance

Optimization Tips

Measuring the Heart Rate

of Motor Systems: 

Electric Current

By Don Casada, Diagnostic Solutions LLC,

Knoxville, TN

Don continues his

series on field measurements. To read

previous columns, go

to Energy Matters

Extra at www.oit.doe.

gov/bestpractices/

energymatters/

emextra and select “Casada’s Corner.” 

The measurement of electric motor current

is used in a variety of ways in industrial

settings. Protective devices, such as fuses

and thermal overload relays, work because

of the heating effect of current, but current

measurements usually rely on the magnetic

field generated by the current passing

through a conductor. Current transformers

(CT)1 are used to estimate this current.

However, other devices, such as Hall-effect

probes are also used. 

Operations and maintenance personnel

use current as an indicator of properly

operating equipment, and use procedures

or log sheets to specify “normal” current

ranges. A newer use of current is to diagnose equipment health. Commercially

available systems alert users to abnormal

conditions, such as very lightly loaded

motors (which might mean, for example,

that a pump is running dry). More sophisticated techniques use information available

in the motor current frequency spectrum to

help evaluate the health of the motor and

the device it drives.

For those of us doing energy work, current measurements often help estimate the

motor load. While we’re fundamentally

interested in measuring input power, which

requires current measurement, current

alone can provide us with a means of estimating power, even when we don’t have or

can’t use a portable power meter. For example, OIT’s Pumping System Analysis Tool

(PSAT)2 uses average motor performance 

characteristics from the MotorMaster+

motor manufacturers database to estimate

electric input power from current measurements3. 

Protective and operations support functtions depend on permanently installed CTs. 

For energy measurements, we often resort

to using temporary, clamp-on CTs, such as

those shown in Figure 1. If a motor has

permanently installed CTs (and you trust

the indicator), those can be used. 

Practical Considerations for Clamp-on CTs

It should go without saying that use of

accurate test equipment is of fundamental

importance. But, there are several important considerations that are specific to the

field use of temporary, clamp-on CTs. 

1. Make sure the jaws close properly. This

is essential to completing the magnetic circuit of the CT. If there are tight clearances

where the CT is used, the jaws can bind

partially open, even when hand tension is

released. The indicated current may be

considerably in error. Figure 2 illustrates

the effect when a fixed load current of

approximately 100 amps was monitored

with a) the jaws of the CT fully closed and

b) a gap of 0.04 inches (less than the thickness of a dime) separating the jaw faces. 

To ensure the jaws are fully closed,

wigggle the probe a bit, making sure it

moves freely and is not bound by adjacent

wires or other obstructions. At higher current levels, a magnetic “buzz” created by a

slight jaw separation can be heard and felt

(through gloves, of course).

2. When possible, measure and average

all three phases. This precaution applies to

both permanent and temporary CTs. A

small unbalance in the supply voltage can

result in a large current unbalance among

Figure 1: Installing a clamp-on current transducer.

Figure 2: Current indicated by current transducer with fully closed jaws (left) and 40-mil gap

(right) with constant load (1 millivolt/amp scaling).

(continued on page 9) ©
Energy Matters, Fall 2001 9

the three phases. As a rule, a 1% unbalance in voltage will result in roughly a 7%

unbalance in current. Even in the presence

of a balanced power supply, there may be

current unbalance on the order of 5%. 

3. Use properly sized CTs. Like most other

measurement devices, CTs lose accuracy

when operated at a fraction of their rated

range. For example, using a 2,000-amp CT

with 0.5% of full span accuracy (which is

excellent) to measure a 20-amp current

may result in a 50% measurement error.

4. Average current on fluctuating loads.

Many motor loads are fluctuating in

nature. The current for belt-driven equipment, for example, tends to fluctuate at

belt- and sheave-pass frequencies. Some

current monitoring devices grab a very

short sample (a few cycles, or milliseconds) of data and display a fixed result.

Other devices continuously update the

data, but the fluctuations make it difficult

to pin down. 

A more representative measurement can

be obtained on a multimeter with a

min/max averaging feature. The multimeter

shown in Figure 2 has this feature (note the

MIN MAX button near the bottom of the

picture). This feature is also helpful in averaging other system parameters that tend to

fluctuate, such as pressure. If no such function is available, several samples can be

statistically averaged. A computer-based

data acquisition system or data logger simplifies the collection and analysis of many

(and/or longer duration) samples.

5. Make sure the current measured is

really the motor current. Power factor-correcting capacitor banks are often used with

induction motors. When capacitors are

used, particular care must be exercised in

selecting the measurement location. The

current from the line to the combination of

the motor and the capacitor bank will be

less than the motor current. This seemingly

contradictory behavior is real, and it

occurs because the current to the capacitor

bank will lead the voltage by 90°, while

the current to the motor will lag voltage by

a variable amount, depending on load. 

If the current will be used to estimate

motor load, such as when it is an input to

PSAT, the current going to the motor

should be measured, not the incoming 

current from the line. Figure 3 illustrates

the error that can occur when this is not 

done. The current to the motor is 22%

greater than the incoming line’s current to

the motor and paralleled capacitor bank.

6. Take safety precautions. This is

absolutely the most important consideration4. A 50% error in the current measurement because of failure to follow

previously mentioned precautions or other

mistakes could result in a poor diagnosis of

equipment health or a loss in company

profits. But, failure to exercise proper safety

precautions during testing (such as wearing

insulated gloves) could result in a poor 

diagnosis for your health or the company’s

loss being you. Be careful out there! ●

E-mail Don Casada at doncasada@icx.net.

1 CT usually refers to current transformer. However, this

discussion equally pertains to Hall-effect probes; for

purposes of this article, CT stands for the broader term,

current transducer.

2 PSAT and MotorMaster+ are available free from the

BestPractices Web site at www.oit.doe.gov/

bestpractices/software_tools.shtml.

3 Author’s note: In my experience, the PSAT estimate of

electric power (made from measured current and voltage) usually agrees with the measured power within a

few percent.

4 From strictly a safety perspective, I definitely prefer an

instrument whose indication is NOT built into the CT.

That way, I don’t have to stick my nose into the electrical cabinet to get my reading.

Figure 3. Motor measurements upstream and downstream of a paralleled capacitor bank.

PF correcting

capacitors

(40 kVAR)

78.4 kW, 81.3 kVA, 0.965 pf

102.0 amps, 460 V

200-hp motor at

50% of rated load

Supply (line)

ABC

78.4 kW, 99.5 kVA, 0.788 pf

124.9 amps, 460 V

Key

hp – horsepower

kVA – kilovolt-amperes

kVAR – kilovolt-amperes 

 reactive

pf – power factor

V – volt

Performance Optimization Tips

continued from page 8

Here are some previous articles by Don

Casada on field measurements. Log on to

Energy Matters Extra at www.oit.doe.gov/

bestpractices/energymatters/emextra to

review these and other columns in

“Casada’s Corner.” 

2000

Field Measurements in Pumping Systems,

May/June—Two methods of estimating flow

rate in systems with no installed flow meters. 

Field Measurements in Pumping Systems,

March/April—Understand pumping system

operations by maintaining a system 

perspective.

1999 

Field Measurements in Pumping Systems,

September/October—Velocity is the third

element of pump head. 

Field Measurements in Pumping Systems,

July/August—Elevation is the second element of pump head.

Field Measurements-Practicalities and Pitfalls in a Parabolic Context, May/June—

Continues the discussion on the changing

picture of system operations. 

Understanding the Changing Needs of Your

Systems, March/April—Understanding the

changing picture of system operations.

1998

How to Cope with Potential Field Measurement Pitfalls, November/December—

Useful assessments of motor system efficiency and reliability depend on getting the

right measurements in the right way. 
10 Energy Matters, Fall 2001

DOE is aiming to increase the use of efficient energy systems across U.S. industry. To

that end, DOE is developing a portfolio of

assessment methods that industry can use to

identify energy- and cost-saving opportunities. One of OIT’s roles in this effort is working in partnership with Industries of the

Future (IOF) to perform plant-wide assessments. These assessments indicate areas in

which plants can significantly reduce

energy use, increase productivity and global

competitiveness, and reduce waste by

implementing appropriate technology.

Through solicitations over the past 3 years,

OIT has provided cost-shared funding and

offered technical assistance to facilities to

conduct such plant-wide assessments.

Specifically, these solicitations seek proposals in which teams consider adopting

best available and emerging technologies

using a variety of tools, information, process

engineering techniques, and BestPractices

plant support and process systems. In addition, projects that can be replicated by other

plants are highly desirable. Only industrial

sites that fall within the IOF strategy areas

are considered for awards. These include

agriculture, aluminum, chemicals, forest

products, glass, metal casting, mining,

petroleum refining, and steel. The purpose

is to demonstrate projects or technologies

that can be replicated by other industries,

particularly in the IOF sector.

OIT launched the plant-wide assessment

effort in 1999 to encourage industrial facilities to identify potential energy savings,

process improvements, and opportunities

for new technologies throughout the plant.

With cost-shared funding and technical

assistance from OIT, such assessments

could facilitate improvements for industrial

plants. So far, OIT has made awards to at

least 23 plant-wide assessment projects.

You, too, are part of the vast potential

for replicating energy savings, cost reductions, and productivity improvements. Get

involved and help your company reap the

benefits. Find out how you can take part in

a plant-wide assessment at the BestPractices

Web site, www.oit.doe.gov/bestpractices/.

For case studies on how plant-wide assessments have helped U.S. companies

improve efficiency and productivity and

reach environmental goals, visit www.oit.

doe.gov/bestpractices/case_studies.shtml#

assessment, or view the Plant Profiles:

Industrial Energy Management in Action

brochure at www.oit.doe.gov/bestpractices/

pdfs/plantprofiles.pdf. ●

OIT Developing Portfolio of Plant-Wide Assessments

Fully 70% of all manufacturing facilities in

the United States use compressed air in

their production processes. In fact, compressed air systems account for 10% of all

electricity use and roughly 16% of the U.S.

manufacturing industry’s motor system use.

However, more than 50% of industrial

plant air systems could be optimized for 

large energy savings—with relatively small

project costs. 

OIT has recently released the Assessment of the Market for Compressed Air Efficiency Services, a comprehensive report of

the compressed air market for services that

lead to compressed air system energy efficiency. The assessment discusses key findings about supply and demand side views

of compressed air system efficiency. This

report is now available online in a PDF format at www.oit.doe.gov/bestpractices/

technical_publications.shtml#market.

Order the report in print from the OIT

Clearinghouse by logging on to www.

oit.doe.gov/clearinghouse, or by calling

800-862-2086. ●

Assessment of Compressed Air Market Now Available

During Phase I, G-P and OIT conducted

an engineering study to define the scope of

a full-scale demonstration of the technology. Process study areas include the

reformer pressure vessel design and refractory system, the product gas clean-up, the

pulse heater pressure design, the system

start-up methodology, the liquor storage

capacity, and the flare system. In addition,

the Big Island mill signed an agreement

with EPA to install and demonstrate the

system under flexible regulatory terms.

Phase I is nearing completion, and Phase

II, which emcompasses gasifier construction and demonstration, will begin shortly.

Site preparation work and demolition of

existing structures is already underway.

For more information on the G-P black

liquor gasification project, visit the OIT Forest Products Web site at www.oit.doe.

gov/forest/pdfs/factsheets/bigisland_va.pdf,

or contact Bob Gemmer, DOE program

manager, at bob.gemmer@ee.doe.gov or

Dan Cicero, DOE project manager, 

National Energy Technology Laboratory, at

dcicer@ netl.doe.gov. Also contact Robert

DeCarrera, Georgia-Pacific Corporation, at 

rdecarre@gapac.com. ●

Black Liquor Gasification

continued from page 6

AMCAST Industrial Corporation in Wapakoneta, Ohio,

performed a plant-wide assessment that resulted in

recommendations for 12 separate projects, including

improvements to the process heating and compressed

air systems. By investing an initial capital requirement

of $1 million, AMCAST is expected to realize annual

energy savings of at least $3.7 million. In addition,

implementing these projects has the potential to

reduce the plant’s carbon dioxide emissions by more

than 11 million pounds per year. The assessment

approach could be applied at other aluminum casting

facilities, and many areas of study could be included

in the analysis of almost any industrial process facility.
Participants in the

Energy Solutions

for California

event met with

exhibitors and

attended presentations to learn

practical ways 

to save energy

and improve 

system efficiency

in their plants.

Energy Matters, Fall 2001 11

Letters to the Editor 

Energy Matters welcomes

your typewritten letters and

e-mails. Please include your

full name, address, organization, and

phone number, and limit comments to 200

words. Address correspondence to:

Michelle Mallory, Letters to the Editor

NREL, MS 1609

1617 Cole Blvd.

Golden, CO 80401

E-mail: michelle_sosa-mallory@nrel.gov

We publish letters of interest to readers

on related topics, comments, or criticisms/

corrections of a technical nature. Preference is given to articles that appeared in

the previous two issues. Letters may be

edited for length, clarity, and style. ●

EDITOR’S NOTES

Megawatt Mix-up

We heard from a few readers about our use

of the term “MW per hour” in the article

“California Cement Plant Battles Electricity

Interruptions with Its Own Cogeneration

Plant,” which appeared in the May/June

2001 issue of Energy Matters. We should

have used “MW” throughout the article

when referring to electrical load. Our sincere apologies to California Portland

Cement Company for the error. Please take

a look at a revised version of the article on

Energy Matters Extra at www.oit.doe.gov/

bestpractices/energymatters/emextra. 

Thanks to the readers who let us know

about the misprint.

A New Schedule for Energy Matters

Beginning with this issue, Energy Matters will be a quarterly instead of a

bimonthly publication. However, each

issue will be expanded to 12 pages instead

of 8 pages. This new format gives us an

opportunity to offer more in-depth coverage of technical topics while “living within

our means.” We hope you will continue to

find the coverage in Energy Matters useful

and informative, and, as always, we welcome your feedback. ●

Check out Energy Matters Extra for additional information on alternative power

sources for industry. You’ll also find more

about OIT and BestPractices assistance.

Get more facts about on-site power

generation by linking to the report Assessment of On-Site Power Opportunities in

the Industrial Sector. Visit the Distributed

Energy Resources Web site and find out

why distributed generation may be part of

your company’s future. Learn more about

the Green Power Marketing Development

Group by linking to its Web site. 

See how wind turbine manufacturing is

becoming an emerging market for IOFs. In

addition, access new BestPractices fact

sheets that document recent energyefficiency projects implemented by participants in the Utah Showcase.

Log on to Energy Matters Extra at www.

oit.doe.gov/bestpractices/energymatters/

emextra/. ●

EXTRA 

In partnership with the California Energy

Commission, OIT’s Best Practices is hosting a series of one-day events to assist California industries in improving system

efficiency and reducing electrical demand.

The first of these events took place on

August 14 in Sacramento, California.

Keynote speaker for the event was California State Senator Michael Machado (D-Linden). Co-sponsoring organizations

included the Association of California

Water Agencies, California Farm Bureau

Federation, California League of Food

Processors, and the California Manufacturers and Technology Association.

More than 200 people participated in

the event that included exhibitors from the

BestPractices Allied Partner program and

speakers offering practical advice and solutions for managing electrical demand and

improving system efficiency. Case studies

of California industries were also used to

illustrate how electricity use can be

reduced by using a systems approach. Participants commented that the event was

“well worth the time” and that they were

“looking forward to more.” 

The next event will be held on January,

16, 2002, at the San Jose McEnery Convention Center in San Jose, California. For information about the January event and a

complete list of participants and case studies

from the August event, go to the BestPractices

Web site at www.oit.gov/bestpractices, or

call 703-748-8608. ●

Energy Solutions for California 
INFORMATION

CLEARINGHOUSE

Do you have questions about 

using energy-efficient process

and utility systems in your industrial 

facility? Call the OIT Information Clearinghouse for answers, Monday through

Friday 9:00 a.m. to 8:00 p.m. (EST).

Fax: 360-586-8303, or access our 

homepage at www.oit.doe.gov/

clearinghouse.

HOTLINE: 800-862-2086

DOE Regional Support Office 

Representatives

■ David Godfrey, Atlanta, GA, 

404-562-0568

■ Scott Hutchins, Boston, MA, 

617-565-9765

■ Brian Olsen, Chicago, IL, 

312-886-8579

■ Gibson Asuquo, Denver, CO, 

303-275-4841

■ Chris Cockrill, Seattle, WA, 

816-873-3299

■ Joseph Barrett, Philadelphia, PA, 

215-656-6957

This document was produced for the Office 

of Energy Efficiency and Renewable Energy at

the U.S. Department of Energy (DOE) by the 

National Renewable Energy Laboratory, a DOE

national laboratory.

DOE/GO-102001-1454 • Fall 2001

T OF ENERGY

DEPARTMEN

U

E

NITED STAT S OFA ERICA

M

Printed with a renewable-source ink on paper

containing at least 50% wastepaper, including

20% postconsumer waste

CAPTURING THE VALUE OF STEAM EFFICIENCY WORKSHOP

■ November 27, 2001, Orlando, FL

For more information, contact Rachel Madan at the Alliance to Save Energy 202-530-4349. 

BUSINESS ENERGY SOLUTIONS CONFERENCE & EXPO

■ November 28-29, 2001, Orlando FL

For more information, contact Ruth Whitlock at the Association for Energy Engineers at

770-447-5083.

ENERGY SOLUTIONS FOR CALIFORNIA

■ January 16, 2002, San Jose, CA

For more for information about this event, log on to www.oit.doe.gov/bestpractices, or call

703-748-8608. Also see page 11 of this issue for more about this series of workshops. 

OIT CUSTOMER APPRECIATION DAY 2002

■ May 8-9, 2002, Washington, DC

For more information, log on to www.oit.doe.gov or call the OIT Clearinghouse at 

800-862-2086. Watch for more details in future issue of Energy Matters.

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, CO 80401-3393

PRSRT STD

U.S. Postage

PAID

Permit No. 258

Golden, Colorado

BestPractices

The Office of Industrial Technologies (OIT)

BestPractices initiative and its Energy Matters newsletter introduces industrial end

users to emerging technologies and wellproven, cost-saving opportunities in motor,

steam, compressed air, and other plantwide systems. For overview information

and to keep current on what is happening

office wide, check out the newsletter—The

OIT Times—at www.oit.doe.gov/news/

oittimes.shtml.

Coming Events

To keep up-to-date on OIT training and other events, check the calendar regularly on

Energy Matters Extra at www.oit.doe.gov/bestpractices/energymatters/emextra.

COMING NEXT ISSUE: 

The next issue of Energy Matters will focus on smart systems with a look at the latest

technologies for improving industrial energy efficiency.