Optimise motor systems

Electric motor systems account for up to 70% of total electricity use in some production settings.

Optimising their use could lead to significant savings.

This involves making low cost operating changes and investing in more efficient equipment when the right time comes.

Contents

  1. Get started
  2. Make a plan to improve your system
  3. Sub-meter high usage activities or equipment
  4. Check motors are running efficiently
  5. Make sure you have the motors with the right amount of power
  6. Check compressors are running properly
  7. ​​Install variable speed and frequency drives
  8. Buy replacement motors
  9. Get funding and support

Get started

Calculate energy use and how to reduce it if your business uses electric motor systems.

According to Carbon Trust’s energy saving guide, motor systems:

  • use up to 70% of total operational energy
  • can cost 10 times their purchase price in annual energy use

With high energy prices the savings from lower consumption are even greater. This can lead to lower bills and reduced carbon emissions for your business.

Make a plan to improve your system

It is important to understand the components of your motor systems as they work together to drive processes.

These include:

  • drives
  • motors
  • transmission
  • driven equipment

The equipment attached to these systems can include pumps, fans, compressors and conveyors.

Start by doing a walkaround to inspect your equipment. Make note of:

  • the technical details on motor name plates
  • the efficiency or ‘IE’ rating of each motor
  • the loads for each motor
  • the age and possible replacement dates for your equipment
  • any noticeable performance or maintenance issues

Minimum efficiency standards for motors and drives increased in July 2021. Check GOV.UK for the full list of legislated requirements.

Decide if you should improve what you have or buy more efficient motors when they come up for replacement.

Sub-meter high usage activities or equipment

To get the most accurate data on electricity use, install a sub-meter to isolate a motor system from the rest of your operations.

Sub-meters measure the energy usage of a particular business activity, area or type of equipment.

This helps identify which parts of your business are the most costly and where you can save.

Simple models that monitor electricity cost as little as £20. These are good for measuring individual appliances or outlets.

To get more accurate data, several companies offer customised services that:

  1. Analyse your energy usage.
  2. Install multiple sub-meters.
  3. Link the meters to monitoring software.
  4. Help you set targets for savings.

Check motors are running efficiently

Operating motors can cost more than the upfront price in as little as two months, so check that they’re running efficiently.

Reducing motor speed by 20% can cut its energy consumption by 50%.

No-cost steps include:

  • labelling switches and turning off when not in use
  • making sure speeds, fans and other settings are optimised and in use
  • cleaning on a regular basis to avoid overheating

Lower cost steps include:

  • interlocking motors to run in coordination with other equipment
  • installing energy sub-meters to find efficiency and performance issues
  • using the Energy Technology List to purchase efficient replacements

Make sure you have the motors with the right power output

According to Carbon Trust, up to 20% of businesses use motors that are overpowered and not fit for purpose.

Check that the kW output by your motor system matches the application that it’s used for.

‘Lightly loaded’ motors might be using unnecessary electricity.

Replace these motors with models that have the right kW output where it’s financially possible.

Check compressors are running properly

Air compressors are essential if you run a business with mechanical processes.

Make sure air compressors run as efficiently as possible by:

  • checking for leaks – a single 3mm hole can cost £2,000/year
  • switching off when not in use – idling uses up to 70% of full power
  • setting pressure at lowest level for each application
  • making sure there is ventilation space around the compressor

While most new air compressors come with digital monitoring systems, you may be able to retrofit or improve older models using digital tools.

An ultrasonic leak detector costs around £500 but will often pay back in under a year.

Electric motors account for two thirds of the energy used in industrial settings.

​​Install variable speed and frequency drives

When you’re ready to invest in new equipment, variable speed or frequency drives can have a major impact on efficiency.

Up to 20% of the energy to power electric motors is wasted in throttling mechanisms used to slow down the flow of air and liquids.

A variable drive avoids this by helping a motor run at the best speed possible for operating demands.

Payback time varies based on:

  • the cost of electricity
  • the size of your motors
  • how much motors can be slowed down to work at peak efficiency

A decrease in speed of 10% will save almost 30% in energy costs.

Buy replacement motors

You might find it helpful to replace motors with more efficient versions if it’s not feasible to optimise your current system.

With higher electricity prices these will pay back more quickly than in the past.

As of July 2021 there are new minimum efficiency standards for motors and drives increased. Check GOV.UK for the full list of legislated requirements.

You can also use GOV.UK’s Energy Technology List to find the most efficient replacement parts.

Motors and drives are no longer eligible for the Enhanced Capital Allowance (ECA) tax break.

However, you might be able to claim the tax break under the Annual Investment Allowance.

The limit of the allowance is £1M up until 31 March 2023.

Ensure that old motors are disposed of responsibly destroyed by an electronics scrap disposal company that is specialised in separating and sorting.

Get funding and support

For larger sites with high energy use, the Industrial Energy Transformation Fund (IETF) provides up to £30M in matching funding per business for a variety of efficiency measures.

The scheme is designed to run until 2028 and is available across the UK.

Phase 3 of the IETF is open for new applications, supporting industry to cut their energy bills and carbon emissions through investing in energy efficiency and low carbon technologies. For queries about the IETF, contact IETF@beis.gov.uk.

Scotland has a similar IETF scheme. If your site is based in Scotland, you can apply for the Scottish Industrial Energy Transformation Fund (SIETF), or contact them at IETF@gov.scot.

Regional programmes and schemes can also help SMEs improve production efficiency.

Check if you’re eligible for finance and support.

You might find it helpful to hire a consultant to assess your operations if your business has financial resources.

Check our case studies to find out how other businesses have cut energy costs and carbon.