Implementing energy management for machinery and processing plants
Energy management doesn’t require a task force to implement. It can be done from the ground up by teaching energy management best practices to all employees at a facility and ensuring good habits don’t die.
Proper energy management allows for an efficient operation of equipment in oil and gas facilities. It also provides opportunities for engineering teams to develop a thorough understanding of energy sources, uses, and ways to improve. This includes efficiently monitoring energy in systems, machinery, equipment, processes, and technologies; how energy is sourced; and investigating better sources of energy, such as cogeneration or waste-heat recovery.
Ideally, energy management is an ongoing effort to find new opportunities to target, implement, and track progress to ensure ongoing energy savings. Managing energy consumption does not have to be a full-time job with a dedicated department or team. Better results can be achieved by making it part of a regular routine in a plant or facility.
Critical elements of energy management
Plants, facilities, and refineries that are successfully managing their energy usage have several elements in common, which can be summarized as critical elements of energy management. These elements include:
- Management support: Commitment from senior engineers and managers is important. A clear strategic leadership on energy management is a key for success.
- Integration: Integration of energy management into the plant’s existing systems and operational procedures.
- Resources: Appropriate sourcing of energy management strategy, energy efficiency assessments, and project implementation with skilled and knowledgeable personnel, and sufficient funds for implementation.
- Proper and realistic goals: Energy efficiency goals can be translated into plant performance goals, which are time-bound, measurable, linked to action plans, and included in management performance metrics.
- Reporting and communication: Implementation of tracking, measurement, and reporting systems to monitor performance as they relate to goals and objectives. Furthermore, Effective internal and external communication, priority placed on energy management and the performance and successes of the plant’s energy management strategy are best communication practices.
Metering energy data
As a rule of thumb, the more data engineers can get, and the more detailed it is, the better. The old-fashioned approach to energy data collection was to manually read meters every few days or even only once per week. This is quite a chore, and weekly data are not as good the data that come automatically from the modern online approach.
The modern approach to energy data collection is to install interval-metering systems that automatically measure and record energy consumption at short, regular intervals between 5 and 15 minutes. Detailed interval energy consumption data make 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 being used at different times of the day, or on different days of the week. Seeing these patterns makes it much easier to find routine—and random—sources of waste in a plant and its equipment.
Finding opportunities to save energy
An important task is how to analyze metered energy data to find waste. The detailed meter data should be effectively employed to find and quantify energy saving opportunities. Looking at detailed interval energy data is the ideal way to find routine waste.
The easiest and most cost-effective energy-saving opportunities typically require little or no capital investment. For example, many facilities have advanced control systems that could, and should, be controlling machinery and equipment, but unknown to facility management, are faulty or misconfigured. These facilities are consequently operating inefficiently with regard to energy usage. One of the simplest ways to save energy is to encourage staff and operators to properly evaluate if control systems are operating according to their specifications to avoid energy waste.
Without having to patrol the facilities day and night, control systems can be monitored to ensure they are turning off unnecessary equipment. A common occurrence is when the operating and standby lubrication oil pumps are working at the same time, which is inefficient and potentially problematic. By investigating a bit, one can easily find the source of the waste by using detailed interval data. It is easy to make reasonable estimates of how much energy is being wasted at different times. Most plants and facilities have a variety of energy-saving equipment and machinery, which requires some capital investments. Many of these, such as replacing electric motors or drives with more efficient ones, should be evaluated if energy consumption is more than normal consumption.
Although detailed metered data would not necessarily indicate these opportunities, it would be useful to help engineers quantify the potential savings that each opportunity could bring. Basing savings estimates on real metered data rather than rules-of-thumb is more reliable and it is critically important to quantify the expected savings for any opportunity into which engineers are considering investing a lot of time and money.
Targeting energy opportunities
Merely finding opportunities to save energy would not help engineers to save energy; one must take action to target them. Engineers must bring energy awareness to the attention of their managers. It can be hard work, but if management can see the benefit, then it can lead to energy savings.
As for those energy saving opportunities that require equipment upgrades—assuming they are properly identified—there is little more to be said. The anticipated savings and payback period must be investigated and presented. The reality is there are some organizations and companies that will not invest in anything with a payback period longer than 6 months.
Tracking progress, following up
After actions have been taken to save energy, it is important to find out how effective those actions have been. Energy savings that come from operational and behavioral changes, such as switching off unnecessary items, require ongoing attention to ensure that they remain effective and achieve their maximum potential.
At the very least, it is necessary to keep analyzing energy data regularly to ensure that systems are run as planned and are not getting worse. It is normal for unmonitored facilities or machines to become less efficient over time. It is to be expected that equipment and machines will break down or lose efficiency, and that operators, technicians, or facility engineers will forget those good energy saving habits.
Therefore, at the very least, a quick look should be taken at energy data every 2 or 3 days, or even once a week, to ensure status quo and that no issues have arisen. It is a real shame when easy-to-fix faults, such as misconfigured control systems, remain unnoticed for months, resulting in huge energy costs that could have easily been avoided.
Amin Almasi is a senior rotating machinery 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 machineries including centrifugal, screw and reciprocating compressors, gas turbines, steam turbines, engines, pumps, condition monitoring and reliability.
Original content can be found at Control Engineering.