General manufacturing opportunities to save

Optimise the use of existing equipment

Improving real-time process data-monitoring and benchmarking can support optimisation of existing equipment. Significant energy savings can be achieved through minimising heat gains and losses, enabling greater control of process temperatures and shutting down equipment when it is not required.

Some examples of opportunities in this area are outlined below.

Implement effective shut-down procedures

Many manufacturing plants have energy-using equipment which is left on when not in operation.

  • Install timers to turn machinery and equipment off or to idle setting when not required (including equipment such as air compressors, air conditioners and lighting).
  • Fix or replace temperamental equipment so that everything can be turned off and on regularly without the risk that it won’t restart.
  • Identify and insulate equipment that continually loses or gains heat when useful services are not being delivered.

Optimise operating temperatures and pressures

Manufacturing plants have equipment operating at different temperatures and pressures. Ensuring all equipment is operating at optimal settings saves energy.

  • Assess pressure requirements to identify opportunities to reduce energy use without impacting on core manufacturing processes.
  • Operate air compressors at the lowest required pressure settings to easily reduce energy requirements for that equipment by 10%.
  • Review air-conditioner or cool-room settings and widen the temperature band where feasible to reduce energy consumption, loads on refrigeration plant and the probability of equipment failure.

Other opportunities should also be explored such as operating extraction fans only when equipment is in use, providing make-up air close to the equipment, and ensuring that the make-up air inlet is closed when equipment is not in use.

Reduce demand in lighting and HVAC systems

There are many ways to improve the efficiency of lighting equipment in manufacturing plants, such as:

  • manual or automated control of lights
  • increased levels of natural daylight, which can reduce electrical lighting loads by up to 70%
  • installation of LED or induction lighting

For more information, see the Lighting technology page.

There are also steps that can be taken to generate energy savings from existing HVAC systems, including:

  • passive solar design techniques to heat and cool air-conditioned spaces by allowing direct sunlight in winter, and natural ventilation for cooling
  • reduced heating and cooling demand through improved building insulation, high-performance glazing, external window shading, proper window coverings, reflective cool roofs and minimising air leakage through the building envelope
  • operating the system only when and where needed,  using timers to control operation and individual zone control to turn off heating or cooling where not required

For more information, see the HVAC technology page.

Optimise operation of motor systems

A motor system includes the motor itself, the components it drives (pumps, fans and air compressors) and its controls. Optimising the operation of a motor system when coupled with best practice motor management can generally deliver energy savings of up to 60%. Optimisation considers the interaction of energy supply and energy demand.

Improve the efficiency of existing equipment

The efficiency of existing equipment can be improved through proactive maintenance, reducing heat loss and optimising the conditions under which the equipment operates. Implementing these opportunities can provide rapid return on investment.

Some examples of opportunities in this area are outlined below.

Minimise heat loss

Investing in insulation for roofs, walls, boilers and pipe work can minimise heat loss and yield energy savings for particular equipment. It also has significant co-benefits through reducing heating and cooling loads.

For example, heat loss from boiler systems will not only negatively impact on the energy required to maintain boiler temperatures, but can also increase requirements for air-conditioning cooling loads. Minimising losses from boiler systems should include attention to insulating boiler valves, steam and condensate return pipes and storage units.

Implement preventive maintenance of current equipment

A preventive maintenance program can have significant cost saving and production benefits.

For motors and pumps, maintenance prolongs equipment life and operating efficiency and identifies potential failures that would cause downtime. A maintenance program can save up to 30% of total motor system energy use. 

Lubricating air compressors and checking for leaks in the distribution network can prevent costly downtime due to equipment failure.

Leak repair and maintenance can reduce the compressed air losses in equipment from 20–50% down to 10%. 

For more information, see the Compressed air technology page.

Invest in equipment upgrades

Energy-efficiency improvements can be achieved through upgrading and replacing inefficient older equipment, with attention to correct sizing of new units. Some examples of opportunities in this area are outlined below.

Invest in more efficient HVAC systems

High-efficiency HVAC units use up to 40% less energy than units that just meet minimum standards. Individual HVAC unit components, such as motors, can sometimes be replaced with high-efficiency versions.

Invest in more efficient motors

Of a motor’s total cost, up to 95% is for the energy used over its life time and only about 5% is for purchase, installation and maintenance. Premium motors also have longer bearing life, longer insulation life and less vibration. They also run cooler, reducing the plant cooling load.

Therefore, investment in a premium motor can pay back the purchase cost many times over with energy savings and indirect cost savings.

The use of variable speed drives combined with high-efficiency motors and improved motor system management can also unlock energy savings.

Invest in more efficient boilers

Modern boilers use timing controls, performance monitoring systems and alarms to avoid dry cycling. Dry cycling occurs when energy is wasted due to a non-operating boiler turning on unnecessarily to recover standing losses. Many older boilers are prone to dry cycling because they have fewer controls, so modern boilers are a better option.

Further efficiencies can be achieved by investing in solar hot water heating systems. These systems save energy by preheating boiler feed water up to 80ºC, which is suitable for a wide range of food and beverage processing plants.

For more information, see the Process heat and steam systems technology page.

Invest in more efficient air compressors

After a compressed air load has been reduced and any leaks in the distribution network have been repaired, a new correctly sized compressor can be installed to increase energy efficiency.

Since air compressors are most efficient when near full load, the best air compressor system is one which is correctly sized for the application. If the load is unavoidably variable, a combination of smaller compressors and/or variable speed drives may meet the load more efficiently. One compressor can meet the base load, with the others coming online to meet peak loads.

There are many types of compressors, including reciprocating, vane, screw, centrifugal, scroll, and rotary tooth. Each type has its advantages and disadvantages, but generally, reciprocating and centrifugal compressors are the most efficient. Peak loads can also be reduced by using storage receivers, which can store 5–10% of compressor capacity.

For more information, see the Compressed air technology page.

Undertake process analysis and integration

In manufacturing plants with multiple heating and cooling demands, process integration saves energy costs through linking hot and cold processes to reduce heat losses and identify heat recovery opportunities.

Pinch analysis aids process integration by identifying and correcting the ‘pinch’ (performance limiting constraint) in a manufacturing plant.

It uses two composite curves—one for heating and one for cooling. Plotting the two curves on a temperature-enthalpy graph reveals the pinch and the corresponding energy targets (minimum feasible energy use for heating and cooling). Heat exchanger networks can then be designed to link processes to meet these targets.

Pinch analyses can be conducted on both new and existing plants.

Implement heat recovery

There are heat recovery opportunities in many manufacturing sectors, especially those with high temperature processes (using metals, chemicals, cement, ammonia and lime manufacturing) and those using steam generation and the use of boilers (paper and pulp manufacturing).

Co-generation systems use heat, steam or waste gases to produce both electrical and thermal energy.

Tri-generation (producing cooling as well as electricity and heat) can be appropriate at some sites.

Co- and tri-generation systems are ideally suited to manufacturing plants as they produce the most energy when the plants need it most, when they are running at close to 100% capacity. Most systems are found in energy-intensive manufacturing sectors, including steel, aluminium, cement, paper and pulp, chemicals and plastics, food and beverage, and petroleum refining. Developments in small scale co-generation such as micro-turbines and fuel cells are also opening up opportunities.

Replace lighting

Replacing ageing fluorescent and high-bay lights with LED or induction alternatives can save substantial energy.

For more information, see the Waste heat minimisation and recovery technology page.

Design products for high-efficiency performance

Manufacturers can gain competitive advantage and build greater customer loyalty through designing products with low life-cycle impacts that require significantly less energy in production and operation.

Some recent energy-efficient product designs include:

  • innovative, lightweight components and materials
  • equipment and appliances with effective standby functions
  • lighting solutions such as LEDs with better illumination and longer lifetimes
  • fuel-efficient and lightweight vehicles
  • insulation materials, double- or triple-glazed windows and other efficient construction materials

Collaborate with supply chains

A collaborative approach to energy and carbon management within the supply chain has the potential to realise large savings by helping participants to better coordinate and optimise the entire production process. Supply chain management also addresses increasing customer expectations around sustainability and helps maintain a competitive edge.

Strategies to improve energy efficiency may include engagement with suppliers to encourage them to invest in energy efficiency opportunities and changing purchasing policies to preference lower embodied energy materials.