Case Study: IL Project
Interruptible Load Partnership

Finalist 2009 Deloitte Energy Excellence Awards - Innovation in Energy Award

Partnership

The IL Partnership comprises Energy for Industry Ltd (EFI), Energy Intellect Ltd (EI) and Energy Response Pty Ltd (ER) - three small energy industry participants.
Energy for Industry brought together the three parties to collaborate to make the IL project happen with EFI providing funding and, through its parent company Meridian Energy, the 24 hour trading and re-dispatch capability that is critical to the project.

Energy Intellect’s technology capability provides the essential smart grid terminals which monitor system frequency at each load and enable the interruption and reconnection of the load.  EI also provide the broad spectrum of back office data services for market compliance.

Energy Response provides the specialised capability of aggregation for the project by managing customers on the demand side and working with the customers to ensure limited impacts on their businesses from providing the IL.

What is IL? 

Interruptible Load (IL) is demand-side management of a customer’s electricity load to earn revenues from the Instantaneous Reserves (IR) market.  IL is a component of the customer’s total electrical load that can be interrupted at times of system emergency on the grid, when loss of generation or transmission leads to frequency drop.  IL is essential for the safety and security of electricity supply.  North Island IL also facilitates transfer of South Island based renewable generation to the North Island via the HVDC.  Smart grid terminals on customer sites sense when the grid is dropping below the acceptable frequency level and automatically switch off the customers’ IL, thus reducing demand on the grid.  Providers are paid for offering into the IR market on a half hourly basis.   On average there are around 10 grid events each year that trigger the IL.

Aggregation

The IL Partnership aggregates relatively small packages of IL, with complimentary and contrasting loads, to offer firm IL into the North Island IR market.  This has enabled smaller industrials and commercial electricity users to participate and earn revenue from the reserves market – previously the IL portion of the reserves market has been the preserve of only the very large industrials such as pulp and paper mills, steel mills and some network companies through hot water ripple control. 
Industry sectors involved as IL providers to the IL Partnership include cold stores and cool stores, water and water treatment, pulp and paper, forestry, dairy, meat, infrastructure, data centres, pools and HVAC.