What is an aggregator?

An aggregator combines lots of sources of energy (generation) or lots of energy users (loads) and control them to increase or decrease energy consumption in real time. This is usually done to avoid a price penalty but can also help avoid overloading the electricity network. If aimed at reducing network load in times of stress, this can attract payments from the network business.

For example, an aggregator might install devices to control battery or hot water systems and turn them all on at a certain time of the day to consume excess energy from renewable generation. It might control batteries or generator to produce electricity at high priced times. The diagram below shows how the aggregator operates by controlling many different energy users and producers.

What does it mean to work with an aggregator?

It involves working with a specialist company who can place bids in the wholesale electricity market and control loads, batteries or generators to optimise revenue. A community group can help recruit customers and explain how aggregation works. It can also vet aggregator offers and select options that will help the community reach its goals and provide benefits.

The aggregator needs to have a minimum amount available before it can bid so it will need many customers in your community and beyond. The aggregator makes money for customers by turning on generators or turning off load when the prices are high. It can also turn on loads when the prices are low to use energy at the lowest price window. This is one way the aggregator can help your community use more renewable energy and/ or save money.

Aggregation suits loads like hot water that can be turned on anytime because the energy is stored. Aggregators can also bid into markets for grid stability (FCAS), both to help raise grid frequency and to lower it. Virtual Power Plants are one form of aggregation, based primarily on controlling batteries.

Benefits of working with an aggregator

• An aggregator works on behalf of individual customers so they don’t have to directly participate in the electricity market.

• An aggregator provides a community energy project with a single point of control over many different types of equipment.

• An aggregator manages the complexities of controlling energy and ensuring customers are paid.

Two main financial flows to consider are shown below:

• Consider how the aggregator is paid for its services.
• Assess how much cheaper energy bills can become when working with an aggregator to control equipment.
• Check who pays for any control equipment that is installed and if it will be compatible for use by other aggregators in future.

Some challenges of working with an aggregator

• An aggregator may need to install specific equipment at each customer site. This would include everyone participating in your aggregation project.

• An aggregator needs to balance the demands of the community with the electricity pricing and network constraint signals. In extreme circumstances the best outcome for community or the electricity network might clash with financial outcomes.

When is working with an aggregator a good choice?

• Working with an aggregator is a good choice when there are a lot of loads that could be controlled - such as hot water, pool or irrigation pumping.

• It is valuable to identify an aggregator who can simplify this very complex area for your community and work with a range of hardware partners to install equipment to enable the control.

Aggregation project examples

Project EDGE: Project EDGE (Energy Demand and Generation Exchange) is a trial to demonstrate an off-market, proof-of-concept Distributed Energy Resource (DER) Marketplace that efficiently operates DER to provide both wholesale and local network services within the constraints of the distribution network.

Mondo: Mondo acts as the aggregator for Project Edge.

Yackandandah Mini-Grid The Yackandandah Mini-Grid also uses the Mondo technology and aggregation. In this case, the purpose is to allow more solar energy and avoid overloading the electricity network.

Project Symphony: The Western Australia Distributed Energy Resources Orchestration Pilot is piloting the orchestration of customer-owned distributed energy resources (DER) such as rooftop solar, batteries and major appliances to participate in a future energy market. Synergy is the aggregator for Project Symphony. Evergen control platform provider. Synergy has partnered with Evergen to provide control systems.

Rheem. Synergy has partnered with Rheem to provide controllable hot water systems.

Onslow remote microgrid: The Onslow remote microgrid uses a PXiSE control platform to manage solar systems, storage and a central power plant, with SwitchDIN controllers at each customer site.

Pooled Energy: Pooled Energy was an electricity retailer dedicated to reducing costs for households with swimming pools by controlling pool pumps, a project supported by [ARENA]. It went into administration during the price rises of winter 2022. Pooled Energy Summary

Other guides and resources

AEMO's NEM registration list can help you understand who is registered to aggregate generators or loads. (Note: a Small Generation Aggregator (SGA), a Market Customer (mainly electricity retailers) and a Demand Response Provider can all aggregate and your potential aggregation partners are likely to be listed in one or more of these categories)

Small Generator Aggregator Fact Sheet

Different Aggregation approches: An overview of different approaches and models for aggregators by Paul McArdle at Watt Clarity.