Energy efficiency audits provide industrial companies with costed options to improve the efficiency of their equipment. An audit typically focuses on equipment that uses a lot of power, like electric motors.
Most electric motors are designed to run at 50% to 100% of rated load but their point of maximum efficiency is usually near 75%. There is also a tendency for equipment to be oversized to maximize reliability at the expense of efficiency, even though this can be costly in terms of energy consumption.
Audits are also great for limited budgets. They provide actionable insights and enable businesses to reduce CO2 emissions, cut utility bills and demonstrate environmental progress to stakeholders and regulations. These actions can mean making just small improvements for big gains.
“Industrial manufacturing consumes about 42% of global electric energy. Around 70% of the electricity consumed by industry is converted into motion by motors that power equipment,” says Mari Haapala, Digital Lead for ABB Motion. “We have developed technologies that can reduce energy consumption across many industries, and it all starts with an energy appraisal. This reduced energy consumption adds up and also helps to achieve net zero carbon targets.”
What is an energy efficiency audit?
An energy efficiency audit, which is sometimes also known as an energy appraisal, is a service for industrial companies to identify opportunities to cut energy consumption and provides recommendations on how to do so. During an audit, an expert measures a plant or system’s energy consumption and compares it with the useful work delivered. This shows anywhere that equipment is using more energy than it needs to. Energy efficiency audits have six steps:
- Identify and understand the problem
- Quantify the energy usage
- Establish energy-saving potential
- Identify potential solutions
- Implementing changes
- Verify and follow up
1. Identify and understand the problem
The first step in an audit or appraisal is for an operator to be aware that they may be able to cut energy demand by improving the efficiency of their electric motors.
There are around 300 million motor-driven systems in use around the world today, and it has been estimated that if these were replaced with higher-efficiency equipment, global energy consumption could be reduced by up to 10 percent.
Every industrial facility is a microcosm of this – the challenge is to identify the installations that offer the fastest return on investment.
2. Quantify the energy usage
Traditionally, an energy efficiency consultant visits the site, reviews processes and equipment, and sets up monitoring equipment to gather data. This can be time-consuming and, therefore, costly.
Fortunately, it is now possible to conduct in-depth audits also remotely. The site’s own maintenance team can deploy digital data-gathering technology across large fleets of motors. The data is then uploaded directly to the cloud, where it is accessed by an energy efficiency expert. Services such as ABB’s Digital Powertrain Energy Appraisal, for example, can gather data from hundreds of devices in the field.
3. Establish energy-saving potential
The energy efficiency expert then reviews the systems and technology used at the facility. This involves evaluating the types and power ratings of motors in service, how they are controlled, their service profiles, and the loading they experience. The analysis enables the expert to identify opportunities for efficiency improvements and quantify the real work output from motors.
Comparing the energy consumption of motors with the work they deliver reveals motors that draw significantly more power than they need. This is where the energy-saving potential lies.
4. Identify potential solutions
The expert then recommends options to improve their performance. Common recommendations can include:
- Adding a variable speed drive (VSD) to adjust a motor’s energy consumption to meet a varying load.
- If the motors are already equipped with VSDs, the entire electric drivetrain (consisting of a motor and VSD) could be upgraded to a modern high-efficiency version.
- Where motors are specified for peak loads that rarely occur in reality, the drivetrain can be replaced with a smaller one, or a different configuration can be used.
- In some applications, the operational schedule can be changed so that the motor only operates near its point of optimum efficiency.
The energy efficiency expert will also develop a financial case for each of the options they have identified. This compares their cost and value. Armed with this insight, it is straightforward for an operations manager to choose the remedial actions that offer the fastest payback.
5. Implementing changes
At this stage, energy-saving actions are implemented on the agreed solutions. This is typically delivered on a project basis, covering an agreed set of assets, applications, and settings.
6. Verify and follow up
As with any project, the final stage is evaluation. For a conventional energy efficiency audit, this requires another site visit to measure energy consumption after implementation.
However, with the latest digital energy appraisal services, it’s also possible to get immediate feedback. Because each individual motor is constantly recording data, the energy expert can easily review the logs and confirm that the changes have achieved the target energy savings.
Benefits of energy efficiency audits in industry
Energy efficiency audits deliver cost savings and environmental benefits. By evaluating and improving efficiency, an industrial operator will save energy. In turn, this will save money, as electricity is often the top operating expense for industrial facilities. This improves productivity and competitiveness.
However, this is not the only reason that facilities conduct energy audits. In some cases, facilities aim to keep their overall energy consumption below an upper threshold. This avoids penalty tariffs that utility companies apply when a business draws more power than is permitted under its contract.
Saving energy also reduces CO2 emissions. This is a sustainability benefit for the operator itself. However, smart operators can create a competitive advantage in sectors where consumers will pay a premium for goods with a low carbon footprint. Audits can also prove to policymakers and stakeholders that the business is complying with tightening environmental regulations and doing its part to free up energy for others in the community.
Future prospects for energy efficiency
Energy efficiency audits help businesses to identify exactly where their best energy-saving opportunities lie. The latest digital technology has made them easier than ever to conduct, making it possible to audit the efficiency of more motor-driven systems than ever before.
Learn more about data-driven energy efficiency appraisals in this white paper: The future is energy-efficient, the future is data-driven.
