In a perfect world, the Maintenance department receives and signs off on all new equipment purchases. The equipment, in turn, is perfectly set up, balanced, aligned, lubricated, and run by fully trained operators in a brand-new, state-of-the-art facility. While this scenario is a reality for some, the majority of Maintenance departments are legacy caretakers of older equipment assets that may not have been designed with energy efficiency in mind.
With the ever-increasing concerns over global ecology and strategies to combat the volatile price of fuels and energy, the Maintenance department can (and must) do more as part of a corporate conservation effort. Maintenance is in an excellent position to take the lead through the development of an energy-conserving asset-management approach. An approach designed to operate over an asset’s entire life span and be implemented by way of a simple three-step process. The good news is this approach can be adopted for any asset, regardless of its current condition or operating context. The key is to follow good asset-management practices.
STEP ONE: UNDERSTAND YOUR ENERGY BILL
If you are to implement a program designed to reduce energy use, you must acquire the right to view the plant’s energy bill. On the other hand, If you are new to energy management and/or have never studied an industrial or commercial energy bill, note that three main charges make up the major portion of a monthly billing:
♦ Demand Charge
♦ Consumption Charge
♦ Power-Factor Adjustment
Demand Charge is a charge for the maximum amount of power (the rate at which work is performed [measured in kilowatts, or kW]) required by the end user during a specified billing period (usually the number of days in a calendar month).
Sometimes referred to as a capacity charge, demand is metered by the utility company using a meter that averages the total instant power demand over short incremental periods (usually every 15 minutes) and is charged to the end user in dollars ($) per kW.
A process referred to as “load shifting” can reduce demand charges significantly. Total grid-energy demands tend to “peak” at certain times of the day (usually late afternoon for one to two hours, depending on the utility location). By shifting your site’s production outside of these peak periods, large demand savings can be accrued. This can be achieved by finding out the exact peak-demand period from your utility, and adjusting shift start and stop times, or by forcing a maintenance window to coincide with all, or a portion, of the peak-demand period.
Consumption Charge is a charge for the total amount of energy consumed within the same billing period. Sometimes known as an “energy charge”, energy consumption measures the amount of work performed and is calculated by multiplying the amount of power times the amount of time the power was used. The consumption charge is billed in cents per kilowatt per hour (kWh) use.
As it does with demand charges, load shifting will reduce consumption charges, as well as energy losses caused by friction and heat. (Reducing friction and heat losses will be the subject of future articles in The RAM Review.)
Power-Factor Adjustment is an expensive penalty charge for inefficient use of power. Sites that use numerous inductive-load devices, such as transformers, fluorescent lights, and lightly loaded electrical motors, will experience inductive loads that cause the amperage and voltage electrical wave forms to go out of phase with one another (the more out of phase, the lower, and less efficient, the power factor.
This phase shift is the difference between the apparent (theoretical) power required (measured in kilovolt-amps, or kVa), and the actual resistive power measured in kW. Ideal power factor is 1, or unity. Acceptable power factor before penalties are applied is usually .9 to .95 (90% to 95%) or higher, depending on the utility. Fortunately, power factor can be raised easily by affixing power-factor correction capacitors to inductive devices.
Billing can be charged under a variety of rate structures. At minimum, ensure your operation is on a “declining-block rate structure,” whereby lower rates “kick-in” at higher consumption levels. Depending on how your plant operates, you may be able to take advantage of “time of use” rates that offer discounts for off-peak energy users.
Utilities also offer a lower cost “interruptible rate” that allow them to temporarily reduce, or halt energy supply at peak demand times. Other utility bill charges can include delivery charges, administrative charges, taxes, and more.
With electrical generation close to full capacity, electrical utility providers react positively to end-user efficiency initiatives. Thus, they typically offer a wide array of energy management/efficiency services and other assistance to end users/customers (often at little or no charge). In many cases, rebates are offered as incentives to those who “follow through” with their respective energy-efficiency programs. Setting up a working relationship with your utility company is essential for assuring energy-efficiency success.
STEP TWO: TAKE/ASSIGN RESPONSIBILITY
Responsibility is about ensuring that any energy losses relating to asset ineffectiveness are under the direct control of the Maintenance department. This requires all heating, cooling, and generated-power systems (including compressed air and steam) to operate at an efficiency level that’s no less than the original minimum design level.
Understanding the direct relationship between asset-management practices and energy use will deliver more control over operating costs for the life of an asset. This, in turn, can lead to increased profits and competitiveness.
STEP THREE: ADOPT A PROACTIVE APPROACH
Previously, the business of maintenance was dedicated to the preservation of an asset through variousassessment, evaluation, adjustment, calibration, prevention, and prediction, repair and overhaul techniques. These methods were used to ensure an asset’s capability to perform based on its original design specification.
The business of asset management differs in that it elevates maintenance to a more proactive and creative process that doesn’t simply review an asset’s current health. It also considers the consequences of that state of health and, and more important, the consequences of the asset’s current usage pattern and any inherent design inefficiencies.
To achieve this, Maintenance must partner closely with the Production department to recognize the integral impact each has on the other and the resulting asset efficiency. Asset efficiency translates to higher levels of reliability, uptime, and throughput, while reducing friction-caused energy spikes and peak/cyclical loading that surpass the asset’s designed load limit. Introducing a value-added maintenance approach and optimizing equipment usage will ensure your assets are as energy efficient as their current design will allow.
Optimized equipment use is best achieved through the collaboration of both maintenance and production planners working to address idle time reduction through improved planning, or use of automated control systems. Studies by the Research Institute for Energy Economics and Financial Analysis (ieefa.org, Lakewood, OH) concluded that in a single eight-hour shift, machine tools were responsible for a disproportionate 30% of total energy consumption when left idling during operation, break, and non-productive time periods.
In a Lean Manufacturing environment, equipment throughout a plant can be slowed down to produce at a lower, but more consistent, rate. This eliminates energy surges when assets are constantly expected to perform, albeit erratically, above their design specifications. If capacity is abundant and idle time still exists, Maintenance may wish to explore turning it into a maintenance opportunity, i.e., use that idle time to perform planned maintenance tasks.
THE FINAL WORD(S)
In today’s world, energy efficiency is mandatory. Maintenance departments can take the lead and help achieve/increase energy efficiency in plants through precision- maintenance programs. Such programs involve tasks that deliver an enormous twofer: a positive impact on asset reliability and energy efficiency.Consider the following:
♦ Implementing a simple operator-led asset-cleaning program will not only provide the ability
to troubleshoot equipment problems faster, but also eliminate the energy-absorbing thermal
blanket caused by machine dirt that converts energy to heat rather than work.
♦ Implementing an engineered lubrication management program ensures delivery of the right
lubricant, in the right place, in the right amount, at the right time, reducing bearing wear and
energy-robbing friction to tolerable levels.
♦ Understanding and practicing correct torquing of fasteners and laser alignment will virtually
eliminate energy-robbing vibration caused by mechanical looseness and misalignment.
If you haven’t already done so, maybe it’s time to reframe your maintenance efforts and make a big (and welcome) difference in your organization’s bottom line, asset health, and, more important, the health of the planet.TRR
Editor’s Note: This article is based on information from the author’s book
Energy Reduction Through Improved Maintenance Practices, 1999;
Industrial Press, South Norwalk, CT; (ISBN-10:0831130822).
ABOUT THE AUTHOR
Ken Bannister has 40+ years of experience in the RAM industry. For the past 30, he’s been a Managing Partner and Principal Asset Management Consultant with Engtech industries Inc., where he has specialized in helping clients implement best-practice asset-management programs worldwide. A founding member and past director of the Plant Engineering and Maintenance Association of Canada, he is the author of several books, including three on lubrication, one on predictive maintenance, and one on energy reduction strategies, and is currently writing one on planning and scheduling. Contact him directly at 519-469-9173 or [email protected].
Tags: reliability, availability, maintenance, RAM, electrical power, energy efficiency, green energy, sustainability
