Best Practice Guide

Food and Beverage Growers and Processors

Introduction

Planning an Energy Program

Funding and Approval

Commissioning

On-the-Farm Energy Use

Lighting

Building Envelope

Central HVAC System

Boilers

Steam

Energy Use Basics

Pipe Configurations

Proper Maintenance

Waste Heat Recovery

Combined Heat and Power

Compressed Air

Refrigeration

Motors

Demand Response

Distributed Generation

Water Use


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J Vineyards and Winery

Mission Foods

S. Martinelli and Company

Sara Lee

Vineyard 29


View the Glossary

Steam

Energy Use Basics

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When thinking about steam systems used in industry and manufacturing, it is helpful to consider the different forms in which energy can take shape. Steam generated at a facility often takes several of these forms and is used in a variety of applications:

  • Thermal energy, e.g., process heat, building heat, hot water.
  • Mechanical energy, e.g., steam-driven equipment.
  • Electrical energy, e.g., steam-driven turbines, cogeneration.

Besides this versatility in form and function, steam has a number of performance advantages, as described by the U.S. Department of Energy (DOE):

  • Low toxicity.
  • Ease of transportation.
  • High efficiency.
  • High heat capacity.
  • Low cost, with respect to alternatives.

Steam is water heated to its boiling point, becoming gaseous rather than liquid. There are three main types of steam: wet steam, saturated steam, and superheated steam. Wet steam has particles of condensed water droplets (condensate) within the water vapor. Saturated steam is steam at the temperature and pressure where all water becomes vapor; there are no water droplets. Superheated steam, also referred to as dry steam, is steam that has either been heated above the point of evaporation with pressure remaining the same, or steam at the temperature of evaporation with reduced pressure; the result is a "dry" steam.

DOE found that, in total, over 45 percent of all fuel burned by U.S. manufacturers is consumed to generate steam, at an annual cost of $18 billion. At the same time, DOE estimates that a typical industrial facility can achieve steam savings of as much as 20 percent by improving its steam system. If improvements were adopted across the industrial sector, manufactures could save as much as $4 billion in fuel costs and eliminate 32 million metric tons of emissions.

Use of steam energy among industries varies. Among the largest industrial energy users, pulp and paper, food and beverage, and chemical manufacturers use a high percentage of steam compared to electricity or direct fuel.

Steam energy usage by major manufacturing groups, in trillion Btu (TBtu)*

SICBuilding SteamProcess and Assembly Steam Total Energy Use% of Steam to Total Energy
20 Food125461,03853.8%
26 Pulp and Paper81,5702,16373.0%
28 Chemicals111,4142,88549.4%
29 Petroleum Refining21,0862,98036.5%
32 Stone/Clay/Glass0209392.1%
33 Primary Metals02692,48810.8%
Metal-based Durables791681,23420.0%
Other Manufacturing794141,21040.7%
Total SIC 20-391905,4861,493438.0%

* Data from "Overview of Energy Flow for Industries in Standard Industrial Classifications 20-39." Prepared by Arthur D. Little, Inc. for the U.S. Department of Energy, Office of Industrial Technology, December 4, 2000.


Resources

U.S. Department of Energy, Best Practices Steam program:

3E Plus - a software program to optimize the installed thickness of mechanical insulation. Helps the user determine fuel savings and emissions reductions under varying operating conditions.

Steam System Scoping Tool - a self-paced checklist for discovering steam improvement opportunities and serves as a scorecard for comparing profiles of one or more plants over time.

Steam Tip Sheets - a series of one-page reference sheets, each of which describes a specific steam improvement opportunity. Tip sheets provide a technical overview and a sample calculation of economic impacts.

Steaming Ahead - this newsletter and companion website give the steam community bi-monthly updates about program products and events.

Ensuring Energy Efficiency Through Effective Monitoring of Steam. Solartron Mobrey Ltd. Reproduced by Energy Solutions Center, Inc., Boiler Burner Consortium.

Yoder, Jesse L., Ph.D. Using Meters to Measure Steam Flow. Plant Engineering Magazine, April 1998. Reproduced by Flow Research, Inc.

Northwest Food Processors Association Efficiency Practices and Emerging Technologies websites offer useful information and tips for the food processing industry.

California Energy Commission websites on Food and Fiber Processing Technologies and Energy in Agriculture.