Energy management in water facilities: Part one

Nov. 7, 2014

Efficient energy consumption can result in significant savings.

Energy management can allow an efficient operation of a water system (or water facility) and its machineries and equipment. It also provides opportunities for engineering teams to develop a thorough understanding of energy sources, energy use and ways for improvement. This includes details to use energy more efficiently in water systems, machineries, equipment and water packages as well as how energy is sourced and consumed.

Ideally “energy management” will be an ongoing effort to find new opportunities to target, implement and track progress of generating continual energy savings. Managing energy consumption does not have to be a full-time job with a dedicated department or team; however, better results can be achieved if it is made part of a regular routine in a water unit or facility.

Critical elements in energy management

Water systems that are successfully managing their energy have several elements in common, which could be summarized as critical components in energy management. These features include:

  • Commitment from senior engineers and managers is important. A clear strategic leadership on energy management is essential for success.
  • The integration of energy management into the water facility’s existing systems and operational procedures.
  • Appropriate resourcing of the energy management strategy, energy efficiency assessments and project implementation with skilled and knowledgeable personnel and sufficient funds for implementation.
  • Energy efficiency goals that can be translated into water system’s performance objectives, which are time-bound, measurable, linked to action plans and included in management performance metrics.
  • Implementation of tracking, measurement and reporting systems to monitor performance in relation to goals and objectives. Effective communication, internally and externally, of the priority placed on energy management and the performance and successes of the water system’s energy management strategy.

Metering energy data

As a rule of thumb, the more data engineers can get and the more detailed it is, the better. The old fashion approach to energy data collection was to manually read meters once every few days or once a week. This is quite a chore; weekly data is not as good as the data that comes easily and automatically from the modern online approach.

The modern approach to energy data collection is to fit interval-metering systems that automatically measure and record energy consumption at short, regular intervals, such as every one, five or 15 minutes. Detailed interval energy consumption data makes it possible to see patterns of energy waste that would be impossible to see otherwise. For example, there is simply no way that weekly meter readings can show how much energy is used at different times of the day or different days of the week and seeing these patterns makes it much easier to find the routine waste in a water system and its equipment.

Finding opportunities to save energy

An important task is how to analyze metered energy data to find energy wastes. The detailed meter data that are collected should be effectively employed to find and quantify energy-saving opportunities. Looking at comprehensive interval energy data is the ideal way to find routine energy waste.

The easiest and most cost-effective, energy-saving opportunities typically require little or no capital investment. For example, an unbelievable number of water facilities have control systems that could, and should, be controlling machineries and equipment well. However, unknown to the facilities management staff, those systems are faulty or misconfigured and facilities are consequently operating unproductively in terms of energy efficiency. One of the simplest ways to save a significant amount of energy is to encourage staff and operators to properly evaluate if control systems of machineries and equipment are operating as per their specifications to avoid energy wastes.

Examine whether staff, operators and operation/control systems are checking and switching unnecessary equipment or items off without having to patrol the water facilities day and night. A common incidence is to see both operating and standby water pumps working together in a “one plus one" water pump system (one operating and one standby), which is inefficient and also could be problematic, leading to some reliability issues. With a little detective work, who or what is causing the energy wastage can usually be figured out.

Using detailed interval data, it is typically easy to make reasonable estimates of how much energy is being wasted at different times — for example, in cases where it is identified that a lot of energy is being wasted by equipment left unnecessarily working. Also, most water units and facilities have a variety of equipment or machinery related energy-saving opportunities available — most of which require some capital investments. Many of these, such as replacing electric motor drivers with more efficient ones, should be evaluated if energy consumption is more than modern norms published in recent references and literature.

Although detailed meter data would not necessarily indicate these opportunities (e.g. it would not show engineers that a more efficient type of electric motor driver or other equipment exists), it would be useful for helping engineers to quantify the potential savings that each opportunity could bring. It is much more reliable to base savings estimates on actual metered data than on general standards alone. Quantifying the expected savings for any opportunity that engineers are considering investing a lot of time or money into is crucial; it is the only way it can be figured out how to hone in on the biggest, easiest energy savings first.

Simply finding ways to save energy is not enough — it takes necessary action as well. For those energy-saving opportunities that require engineers to motivate the managers, certain guidelines on “energy awareness” should be useful. It can be hard work, but if someone can get the management team on his or her side, it can create some big energy savings.

As for those energy-conserving opportunities required to upgrade equipment, assuming they are properly identified, there is little more to be said. The justification and economic figures should properly be prepared and correctly presented to decision-making managers. Anticipated savings and payback periods should correctly be investigated and presented. The reality is there are some organizations and companies that would not invest in anything with a payback period over four to six months.

In next month's Part two, tracking progress and energy management in water pumps will be discussed.

Amin Almasi is a rotating machine consultant in Australia. He is chartered professional engineer of Engineers Australia (MIEAust CPEng – Mechanical) and IMechE (CEng MIMechE) in addition to a M.Sc. and B.Sc. in mechanical engineering and RPEQ (Registered Professional Engineer in Queensland). He specializes in rotating machines including compressors, gas turbines, steam turbines, engines, pumps, condition monitoring and reliability. Almasi is an active member of Engineers Australia, IMechE, ASME, and SPE. He has authored more than 100 papers and articles dealing with rotating equipment, condition monitoring and reliability.

About the Author

Amin Almasi

Amin Almasi is a mechanical engineer in Australia. He is chartered professional engineer of Engineers Australia (MIEAust CPEng – Mechanical) and IMechE (CEng MIMechE) in addition to a M.S. and B.Sc. in mechanical engineering and Registered Professional Engineer in Queensland (RPEQ). He specializes in mechanical equipment and machineries including pumps, condition monitoring, reliability, as well as power generation, water treatment and others. Almasi is an active member of Engineers Australia, IMechE, ASME, and SPE. He has authored more than 150 papers and articles dealing with rotating equipment, condition monitoring, power generation, water treatment, material handling and reliability.

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