IEEE Power & Energy Magazine - September/October 2021 - 86

recommends Western Power assess its existing visibility
capability, leading to an investment plan for deploying
equipment to enhance network visibility.
In the National Electricity Market, a DER register was
established to capture a range of metadata for installed and
newly installed DER devices. The roadmap recommends
a similar register be created for SWIS to enable AEMO to
refine its forecasting and efficiently manage its system and
market operations. AEMO and Western Power have overseen
the addition of data for approximately 90% of DERs
installed in SWIS. The ongoing DER register was expected
to " go live " in early 2021.
Electric Vehicle Integration
Electric vehicle (EV) uptake has been exceptionally slow in
Western Australia, and it is not expected to have an impact on
SWIS before 2025. However, the future cost of technologies,
customer sentiment, and local or national government policies
remain uncertain. The capacity of EV batteries is significantly
larger than storage systems currently being installed in
SWIS. Their operation will likely have a sizeable impact on
SWIS. The timing and location of charging infrastructure for
EVs also present significant risks and opportunities.
The roadmap recommends that Western Power begin
planning work for the integration of EVs in the grid. This
work is to consider the location of household and larger fastcharge
infrastructure and trials to test and understand the
capabilities of vehicle-to-grid technology.
DER Roadmap: Tariffs and Investment Signals
As noted previously, current tariff structures in Western
Australia do not provide appropriate signals for grid-efficient
behavior. Residential customers in the SWIS pay a
fixed charge per connection (of AUD$1.05/day) and a flat
rate (of AUD$0.29/kWh) (pricing as of 2020-2021). Additionally,
at the time of writing the roadmap, buyback payments
for energy exports were offered under the Renewable
Energy Buyback Scheme (REBS) at a flat AUD$0.07/kWh.
This rate is above the weighted average wholesale energy
cost in the middle of the day (which, in recent years, has
been around AUD$0.03/kWh and could decline further with
energy prices in the Western Australian Wholesale Energy
Market recording negative values with increasing regularity
at this time of day).
Tariff Pilots
The roadmap finds that current tariff structures are incompatible
with a high DER energy system and result in significant
cross subsidies benefiting those with rooftop solar
PVs. The roadmap recommends tariff pilots to encourage
customers to consume energy in a way that supports the grid.
The pilots will help policy makers understand how alternative
tariffs can play a role in promoting efficient investment
in and the use of DERs, including batteries, and to share the
benefits of efficient behavior with customers.
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A time-of-use tariff that provides a strong incentive to shift
consumption to between 9 a.m. and 3 p.m. with a variable rate
of AUD$0.08/kWh during the middle of the day is currently
under trial. This tariff provides customers with a willingness
to shift load with a clear price signal to do so either through
behavior change or some form of automation.
In August 2020, REBS was superseded by the Distributed
Energy Buyback Scheme (DEBS) for households with
new or upgraded solar PV systems. DEBS introduces timeof-export
pricing for household energy exports and offers
buyback to exports from battery and electric vehicles for
the first time. Instead of a flat AUD$0.07/kWh, households
were offered AUD$0.10/kWh for exports between
3 p.m. and 9 p.m. and AUD$0.03/kWh at all other times. This
change provides customers with a further incentive to shift
consumption to the middle of the day (to increase self-consumption)
and a price signal to install west-facing rooftop
PV panels to maximize generation during peak load periods.
While DEBS represents a modest reduction to total buyback
payments for a typical system, it was generally well
received by customers and industry and across the sector. At
the time of writing this article, it has not affected household
PV installation rates. As well as more efficient investment
in DERs, DEBS has played a role in raising awareness and
educating households about the different values of energy at
different times of the day.
DER Roadmap: DER Participation
The theme's objective is to build a future where customers with
solar, storage (including EVs), and other small-scale devices
can be active participants in the power system. It is envisaged
that this will be done by aggregating many small devices to
provide electricity services and act as a " virtual power plant. "
While there have been many trials that test DER aggregation
on a small scale, the DER Roadmap envisages that
most DERs will need to be managed or directed, at least
in a basic way, to ensure that the future power system can
be managed securely and safely. Few, if any, jurisdictions
are operating with DERs as a central participant in power
systems and markets.
Existing regulatory and market structures that are built
around single-direction energy flows do not conceive of
DERs as a participant in the same way as utility-scale generators
or large facility demand-side participation. A change
in thinking in operational rules, practices, and procedures is
needed to enable a true transition to two-way power flows.
To achieve this for SWIS, the DER Roadmap recommends
a DER orchestration pilot to serve as a crucial test of DER
aggregation capability. This will enable customers' devices
to provide services to the network operator and participate
in the wholesale energy market, including the provision of
essential system services where the DERs have the capability.
An end-to-end virtual power plant pilot (Project Symphony)
will demonstrate DERs' ability to support the power
system. This includes helping solve local network issues and
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