Reducing electricity costs with load shedding

Industrial and commercial buildings are increasingly energy hungry with information technology hardware and appliances adding to HVAC and lighting loads. Combined with increasing energy prices, building managers and owners are looking for ways to reduce costs. There are a number of opportunities available to improve energy use and efficiency by eliminating waste through process optimisation. Load shedding is one of the options available to better manage electricity usage and reduce costs.

Across Australia the cost of retail electricity has been rising due to increases in wholesale market prices, this is due in part as a result of high gas prices, limited gas availability on the East Coast, the closure of coal-fired generators and an uncertain policy environment. To combat this, large industrial and commercial business have made a move towards better managing their electricity usage by employing load shedding systems.

Minimising demand and reducing costs

Load shedding is the process of ‘switching off’ certain loads (devices or appliances that consume power) that are surplus to requirements, either manually or automatically.

By implementing load shedding, the demand charge cost of a building’s electricity bill can be reduced by temporarily shutting down non-critical devices or applications.

Buildings which utilise load shedding can make considerable savings on their demand charge, which alone can make up as much as 60 per cent of the electricity bill. Provided there are enough non-essential loads that can be shed, the demand charge can be reduced by as much as 10 to 30 per cent.

Geoff Bladon, Business Development Director at Automation IT, outlines the benefits of implementing automated load shedding systems for industrial and commercial buildings.

“Once peak periods have been identified and non-critical loads determined, building managers can schedule shedding to occur at certain times during the day and the form that the load shedding takes. For example, in an office building, the lights in certain areas can be dimmed during times when natural light is good and load is high in other areas,” Mr Bladon said.

Maintaining power system stability

Industrial and commercial buildings typically have both essential and non-essential power requirements, and in most cases the non-essential loads can be reduced or removed altogether without impacting the buildings ability to provide safe and reliable power to essential loads.

Load shedding systems respond to a loss of generation by automatically shedding loads when a power loss event occurs, this minimises the amount of power required to run essential loads and assists with overall stabilisation of the power generation system.

Load shedding design

Most load shedding designs are integrated into automated networked control systems (NCS) which utilise SCADA, PLC, RTUs and slave devices to monitor, control and shed loads as required.

Mr Bladon said the design of the load shedding system is integral to its success, and requires a thorough understanding of the network under consideration, including all essential and emergency service loads.

“Load shedding can be challenging to set up in commercial and industrial buildings because of their energy requirements and the need to avoid interference with daily operations. Furthermore, all buildings are different and require their own unique load shedding systems. If these factors are not taken into account when designing the system, there is the risk that daily operations could be interrupted, the safety of the building and its occupants compromised, or electricity savings targets will not be met.

“At Automation IT, we have numerous expert electrical and automation engineers, including highly experienced RPEQ registered engineers, who have considerable experience in designing and commissioning fully customised load shedding and energy management solutions for commercial and industrial buildings,” Mr Bladon said.

“Automation IT offers the highest levels of service and safety considerations to ensure each system will provide specific energy savings while also keeping the building, and those that work or live there, functioning optimally and safely.

“Automation IT also creates fully-documented control system code, which complies with all laws, standards and warranties, and makes the operation and future maintenance of the system easier.”