IEEE Power & Energy Magazine - July/August 2021 - 49

12
10
8
6
4
2
12
10
8
6
4
2
0.97 0.98 0.99
1
Voltage Ratio
(a)
Blue-Red
Red-White
1.01 1.02
12 3 456
No-NAC Battery Use (kWh)
(b)
White-Blue
figure 7. The relationship between Shapley value payments and drivers of network benefits by customer phase (dot
color): the (a) voltage ratio and (b) battery use without NAC.
plots show that the red-white phase-connected customers,
circled in the red dash, receive no payment because, in this
particular event, only the blue line current was exceeding the
thermal limit.
Second, the ratio of the voltage at the line current measurement
point over that at each customer's premises is used
as an indicator of the electrical distance and system state
in Figure 7(a). The upward-sloping line indicates that the
greater the drop in voltage to the customer, the greater the
payment. Customers who were further from the constraint
point, in more heavily loaded parts of the network, and on
the most heavily loaded phases received the highest payment.
Third, the counterfactual use of the battery without
NAC in [Figure 7(b)] is negatively
related to payments, showing that
the Shapley value only provides
payments for marginal benefits, so
if a customer's battery is going to
be discharging in any case, it is not
compensated for this action. This
also explains the outliers circled
in blue on the plot of Figure 7(a).
From these results, the correlation
between Shapley value payments
and value to the network is
clear, which demonstrates that the
Shapley value provides a means
to implement value-reflective network
support payments.
In addition to the network benefits,
we also wanted to understand
the extra value proposition for consumers
that the PVs, batteries, EMS,
and NAC participation brings. Customers
benefit from different parts
july/august 2021
1,250
1,000
750
500
250
AU$115
AU$134
AU$104
AU$752
AU$1,105
of the system by varying amounts. To assess this, we again
applied counterfactual simulations to assess the incremental
value of including increased sophistication to the customer's
system and integration with the NAC. The waterfall diagram
in Figure 8 illustrates this.
The first increment is the average cost reduction to trial
customers for installing a PV unit. Note that the PV unit's
value to a customer depends on the average daytime load and
the size of the unit that he or she installs: the larger the average
daytime load and PV unit, the greater the benefit. The
second increment shows the value of adding a battery that
employs a self-consumption maximization heuristic controller,
which is a standard approach in many out-of-the-box
PVs
(No Battery)
PVs + Battery
(With SCM
Only)
+ Reposit
Battery
Controller
+ Network
Support
Total Cost
Reduction
figure 8. The breakdown of average customer cost reductions by system component.
SCM: self-consumption maximization.
ieee power & energy magazine
49
Shapley Value Payment,
No Lower Bound (AU$)
(AU$)
Shapley Value Payment,
No Lower Bound (AU$)

IEEE Power & Energy Magazine - July/August 2021

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