IEEE Power & Energy Magazine - September/October 2021 - 80

Onslow DERMS: DER Integration in Action in Western Australia
Challenges in Horizon Power Area: Hosting Capacity,
Desire to Add More Renewables
Horizon Power is responsible for providing safe and reliable
electricity to more than 100,000 customers by operating
the North West Interconnected System and 34 isolated
microgrids throughout remote regions of Western
Australia.
The well-documented technical challenges, such as
reverse power flow along with the intermittent nature of
solar generation causing power quality and reliability issues,
means there are physics-based technical limits to
how much solar can be connected to an electricity system.
Since 2009, Horizon Power has carefully managed these
technical challenges, which are exacerbated in smaller
isolated microgrids, and currently has implemented renewable
energy hosting capacity limits across 15 of its
microgrids.
Horizon Power considers hosting capacity limits to be
a necessary, but temporary, measure. Over the past few
years, it has been working on several DER " orchestration "
trials as the key to overcoming the technical barriers to connecting
higher levels of rooftop solar.
DER orchestration is achieved through the visibility and
control of all DER connected to the network and includes
communication with rooftop solar inverters, battery storage
inverters, and large household loads (e.g., air conditioning)
using the IEEE 2030.5 Standard for Smart Energy Application
Protocol.
Passive customer assets are effectively integrated into
the planning and operation of the Onslow microgrid in a
way that enables greater customer choice and access to the
greater benefits of renewables. At the same time, it unlocks
the value of aggregated rooftop solar as the cheapest future
source of energy and uses DERs to reduce or avoid the need
for costly generation or network solutions to meet future
energy demand.
While Horizon Power has successfully delivered DER orchestration
projects in Carnarvon and Broome over the past
few years, it is the Onslow DER project that applies DER orchestration
at a scale of an entire town. This is a potentially
transferable solution to removing hosting capacity limits
and enabling greater participation and value from DERs
across its entire service area.
Onslow Context
Onslow is a small coastal town located in the Pilbara region
of Western Australia with a relatively transient population
of fewer than 1,000 residents. In 2016, there was a
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need to renew Onslow's power network assets to meet the
growing needs of this natural gas and mining region.
Project Outline
Horizon Power initiated the Onslow DER project to validate
the forecast that lower cost energy could be achieved
by more than just utility-owned and -operated assets, that
is, supplemented by the aggregation of customer rooftop
solar. This required a solution that could safely and reliably
integrate high levels of customer-owned rooftop solar
to deliver a clean energy future that delivers value to
customers.
The main objectives of the project were to
* safely integrate customer and network DERs to supply
> 50% of Onslow's annual energy
* design, build, and operate a functional energy resources
management system to economically integrate high
levels of DERs, much of which would be customerowned
in tandem with a centralized gas generation
power station
* partner with customers to incentivize the uptake of
controllable DERs.
The technical rooftop solar hosting capacity in Onslow is
~850 kW, beyond which power quality is compromised, and
more rooftop solar cannot be accommodated. To achieve
> 50% of annual energy being met by renewable energy, the
project set a target of achieving uptake of 2 MW of highly
distributed rooftop solar and up to 1 MWh of small-scale
customer battery energy storage systems (BESS) by local
households and businesses.
The resulting time-varying power flows would need to
be " orchestrated " along with the in-place utility-owned
1-MW solar farm, two utility-owned 1-MWh BESS, and
all in tandem with the centralized gas-fired Onslow power
station.
Customer and Community Participation
Active customer and community participation in the Onslow
DER project would be critical to its success. To achieve
the target of 2 MW of rooftop solar, Horizon Power provided
an upfront incentive of 50-75% discounts to Onslow
customers on the purchase of a 3- or 5-kW system. This
meant over 50% of households and small businesses would
need to participate, most of which were renters or living in
corporate or government housing.
As such, the project focused on the principles of " better
engagement " through placing customers, key community
stakeholders, and " local champions " at the center of the
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