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The Lean and Energy Toolkit
Chapter 4: Energy Reduction Tools and Strategies
On This Page
- A. Use Total Productive Maintenance to Reduce Equipment Energy Waste
- B. Replace Over-Sized and Inefficient Equipment with Right-Sized Equipment
- C. Design Plant Layout to Improve Flow and Reduce Energy Use
- D. Encourage Energy Efficiency with Standard Work, Visual Controls, and Mistake-Proofing
This chapter describes best practices for reducing energy use with Lean methods, focusing on process-level opportunities. It includes the following strategies:
- Use Total Productive Maintenance to Reduce Equipment Energy Waste
- Replace Over-Sized and Inefficient Equipment with Right-Sized Equipment
- Design Plant Layout to Improve Flow and Reduce Energy Use
- Encourage Energy Efficiency with Standard Work, Visual Controls, and Mistake-Proofing
A. Use Total Productive Maintenance to Reduce Equipment Energy Waste
Total productive
maintenance (TPM) is a Lean method that focuses on optimizing the effectiveness
of manufacturing equipment. TPM builds upon established equipment-management
approaches and focuses on team-based maintenance that involves employees
at every level and function.
What Is TPM (Box 13)
- The goal of TPM is to build a robust enterprise by maximizing production system efficiency (overall effectiveness).
- TPM addresses the entire production system lifecycle and builds a concrete, shopfloor-based system to prevent all losses. It aims to eliminate all accidents, defects, and breakdowns.
- TPM involves all departments, from production to development, sales, and administration.
- Everyone participates in TPM, from the top executive to shopfloor employees.
- TPM achieves zero losses through overlapping team activities.
Source: The Japan Institute of Plant Maintenance, eds., TPM For Every Operator, (Portland, OR: Productivity Press, 1996), p 11.
Six Big Losses That Lower Equipment Efficiency
Increased equipment operating
efficiency reduces energy waste. When machines are optimally tuned to
accomplish the desired work, energy inputs are most efficient. TPM’s emphasis on
equipment efficiency can lead to reduced costs, increased productivity, and
fewer defects. TPM focuses on the six big losses that lead to equipment inefficiency:
- Breakdowns
- Setup and adjustment loss
- Idling and minor stoppages
- Reduced speed
- Defects and rework
- Start and yield loss
Eradicating the six big losses maximizes the productivity of equipment throughout its lifetime. With proper equipment and systems maintenance, facilities can reduce manufacturing process defects and save an estimated 25 percent in energy costs (1).
Consider using one or more of the Four Strategies for Integrating Energy-Reduction Efforts into TPM (Box 14) to improve energy and equipment efficiency at your facility. This chapter focuses on describing energy savings opportunities associated with autonomous maintenance (strategy #1); other parts of this toolkit provide guidance on identifying energy wastes, conducting energy kaizen events, and developing energy management systems (strategies #2-4).
Four Strategies for Integrating Energy Reduction Efforts into TPM (Box 14)
- Integrate energy-reduction opportunities into autonomous maintenance activities
- Train employees on how to identify energy wastes and how to increase equipment efficiency through maintenance and operations
- Conduct energy kaizen events to make equipment more efficient
- Build energy-efficiency best practices into systems for management of safety, health, and environmental issues
Autonomous Maintenance Improves Energy Efficiency
One distinctive aspect
of TPM is autonomous maintenance. Autonomous maintenance refers to ongoing
maintenance activities operators undertake on their own equipment. Typical
activities include: (1) daily inspections, (2) lubrication, (3) parts
replacement, (4) simple repairs, (5) abnormality detection, and (6) precision
checks. Autonomous maintenance provides an opportunity to integrate process-level
energy-reduction strategies into ongoing equipment maintenance.
Many simple
energy efficiency best practices can be implemented without extensive
analysis or effort. Autonomous maintenance already captures a number of best
practices, such as cleaning, proper lubrication, and standardized maintenance
practices. Your facility can enhance TPM effectiveness by integrating energy-reduction
best practices for specific types of processes into ongoing autonomous
maintenance activities.
Use checklists such as the Energy-Reduction Checklists
for Combustion, Steam Generation, and Process Heating Systems (Box 15)
to identify opportunities to decrease energy consumption while also increasing
equipment efficiency. These checklists are based on best practices compiled
by the U.S. DOE’s
Energy Efficiency and Renewable Energy Department.
Energy Reduction Checklists for Combustion, Steam Generation, and Process Heating Systems (Box 15)
Combustion Systems
- Operate furnaces and boilers at or close to design capacity
- Reduce excess air used for combustion
- Clean heat transfer surfaces
- Reduce radiation losses from openings
- Use proper furnace or boiler insulation to reduce wall heat losses
- Adequately insulate air or water-cooled surfaces exposed to the furnace environment and steam lines leaving the boiler
- Install air preheat or other heat recovery equipment
Steam Generation Systems
- Improve water treatment to minimize boiler blowdown
- Optimize deaerator vent rate
- Repair steam leaks
- Minimize vented steam
- Implement effective steam trap maintenance program
Process Heating Systems
- Minimize air leakage into the furnace by sealing openings
- Maintain proper, slightly positive furnace pressure
- Reduce weight of or eliminate material handling fixtures
- Modify the furnace system or use a separate heating system to recover furnace exhaust gas heat
- Recover part of the furnace exhaust heat for use in lower-temperature processes
Source:
U.S. DOE, Energy Efficiency and Renewable Energy Website, “20 Ways
to Save Energy Now.” www.eere.energy.gov/consumer/industry/20ways.html 
,
accessed 13 June 2007.
By training operators on energy-reduction best practices and checklists applicable to manufacturing processes and equipment at your facility, operators will be better able to save energy in their day-to-day operations and maintenance activities.
B. Replace Over-Sized and Inefficient Equipment with Right-Sized Equipment
Lean
thinking often results in the use of right-sized equipment to meet production
needs. Right-sized equipment is designed to meet the specific
needs of a manufacturing cell or an individual process step, rather than
the processing needs for an entire facility. For example, rather than relying
on one large paint booth or parts cleaning tank station to service all painting
and degreasing needs for a facility, Lean principles typically lead organizations
to shift to right-sized paint and degreasing stations that are embedded
in manufacturing cells.
In conventional manufacturing, equipment often is over-sized to accommodate the maximum anticipated demand. Since purchasing a new large piece of equipment is often costly and time-consuming, engineers often design in additional “buffer capacity” to be sure that the equipment does not bottleneck production. Box 16 shows results from recent studies documenting equipment over-sizing.
Over-Sized Equipment (Box 16)
- Over-sizing building fan systems, on average, occurs by 60 percent
- Most chillers are oversized by 50–200 percent
- Potential energy savings from rightsizing, energy-efficient motors, and variable speed drives is 50–85 percent
Source: U.S. EPA and DOE, ENERGY STAR Program, “Partner
Resources for HVAC contractors”
, accessed
13 June 2007.
Since right-sized equipment is geared toward a specific
end use and production capacity, it often is much more energy efficient than
conventional, large equipment.
Large, “monument” equipment often runs well below capacity, significantly
reducing energy efficiency per unit of production. For example, the natural
gas or electricity needed to fire a large dryer oven is typically the same
whether the line is being run at capacity or if only a few parts are being
processed.
Three Ways to Right Size Your Fan System (Box 17)
- Use smaller, energy-efficient motors. Rightsizing a 75-horsepower (hp) standard efficiency motor to a 50-hp energy-efficient motor will reduce your motor energy consumption by about 33 percent
- Use larger pulleys. Replacing an existing belt-driven pulley with a larger one will reduce its speed, saving energy costs. Reducing a fan’s speed by 20 percent reduces its energy consumption by 50 percent
- Use static pressure adjustment variable air volume (VAV) systems only. Reducing static pressure in your VAV system reduces the fan horsepower consumption. By gradually reducing the static pressure setpoint to a level low enough to keep occupants comfortable, you will reduce energy consumption
Source: U.S. EPA and U.S. DOE ENERGY STAR
Program, Building Upgrade Manual, December 14, 2004. www.energystar.gov/ia/business/BUM.pdf ,
accessed 13 June 2007.
C. Design Plant Layout to Improve Flow and Reduce Energy Use
Lean thinking
focuses on improving the flow of product through the production process.
Facilities arrange equipment and workstations in a sequence that supports
a smooth flow of materials and components through the process, with minimal
transport or delay. The desired outcome is to have the product move through
production in the smallest, quickest possible increment (one piece). Improving
the flow of product and process inputs can significantly reduce the amount
of energy required to support a production process. Box 18 provides an example
of the significance of plant layout and flow in reducing energy use.
Flow and Energy Use (Box 18)
- Dutch engineer Jan Schilham (Interface Nederland) redesigned a heat transfer pumping loop originally designed to use 70.8 kW of pumping power to use 5.3 kW—92 percent less—with lower capital cost and better performance. The new design cut the measured pumping power 12 times and only took a change in design mentality. Lessons learned include:
- Use big pipes and small pumps rather than small pipes and big pumps. Optimizing the whole system together will yield fat pipes and tiny pumps, leading to dramatically decreased operating costs.
- Lay out the pipes first, then the equipment. Installing the pipes before the equipment will decrease pipe friction and allow equipment to be optimally located to improve overall production flow.
Source: Amory Lovins.
Energy End Use Efficiency, September 2005, pp. 16-17. (Commissioned
by InterAcademy Council, Amsterdam, www.interacademycouncil.net ,
as part of its 2005–06
study, “Transitions to Sustainable Energy Systems.”)
D. Encourage Energy Efficiency with Standard Work, Visual Controls, and Mistake-Proofing
Standard Work and Energy Use
Standard work is an agreed-upon set of work procedures
that establish the best and most reliable method of performing a task
or operation. The overall goals of standard work are to maximize performance
while minimizing waste in each operation and workload. Standard work
is the final stage of Lean implementation in that it helps sustain previous
Lean improvements and serves as the foundation for future continuous improvement
(kaizen) efforts.
Your facility can maximize Lean and energy gains by incorporating energy reduction best practices into standard work (e.g., consider drawing from the Questions for Understanding Energy Use and the Energy-Reduction Checklists in Boxes 6 and 13 of this toolkit). Example uses of standard work include:
- Build energy reduction best practices into training materials, in-house regulations, and standard work for equipment operation and maintenance
- Include energy reduction tips in weekly team meetings and monthly facility newsletters
- Add energy reduction best practices into “shine” checklists used when implementing 5S (or 5S+Safety) (2)
Visual Controls
Example Visual Control (Figure 6)
Visual controls are used to reinforce standardized procedures and to display the status of an activity so every employee can see it and take appropriate action. Visual controls also standardize energy and equipment use best practices and can be adopted facility-wide along with other in-house standards.
These easy-to-use cues can be as simple as the following techniques:
- Color-code pipes and other facility conveyances to help operators quickly identify and report key information (e.g., leaks)
- Install a sign over on/off switches or power outlets to remind operators to turn off or unplug equipment that is not in use (for example, see figure 6)
Visual controls also provide a powerful way to track actual results against targets and goals, and encourage additional improvement. Figure 7 shows a dashboard representation of how energy use and cost at a facility compares to annual goals.
Dashboard Visual Controls (Figure 7)
Mistake-Proofing
Mistake-proofing (also known by the Japanese term poka-yoke)
refers to technology and procedures designed to prevent defects and equipment
malfunction during manufacturing processes. Mistake-proofing is used
by manufacturers to prevent and easily identify operational errors; it offers
an unobtrusive approach to standardizing equipment use. One simple energy-efficient
action is to automatically power down energy-consuming equipment when not in
use. Process equipment and lighting do not always need to be on or energized.
Mistake-proofing devices such as occupancy sensors and lock-out/tag-out de-energizing
steps are a simple, low-cost means to power down equipment that is not in use.
By mistake-proofing equipment, a facility can waste less energy, time, and
resources, as well as prevent rework.
To Consider
- Which of the Lean techniques mentioned in this chapter—TPM, flow, right-sized equipment, standard work, visual controls, and/or mistake-proofing—does your organization use?
- What ideas do you have for using Lean techniques to integrate smart energy habits into your organization’s work?
Footnotes
1. Manufacturing Extension Partnership of Louisiana, “Energy Management.” mepol.org/site.php?pageID=180, accessed 13 June 2007.
2. 5S is a Lean method involving
five steps (Sort, Set in order, Shine, Standardize, and Sustain) to establish
a clean, neat, and orderly workplace. Many companies add a sixth “S” for
Safety.