IEEE Power & Energy Magazine - March/April 2017 - 37

march/april 2017

Dist. Equip.
Energy
Losses
Carbon
Capacity
DER Cost
DER Energy
DER Losses
DER Capacity
DER Carbon
Total

Incremental Cost (cents/kWh)

Dist. Equip.
Energy
Losses
Carbon
Capacity
DER Cost
DER Energy
DER Losses
DER Capacity
DER Carbon
Total

Incremental Cost (cents/kWh)

configurations. The levelized cost
of employing DERs to serve load
90
90
growth on the SCE radial feeder
80
80
was 41.1 cents/kWh of load growth
70
70
accommodation, substantially more
60
60
15.5
22.2
50
50
than the cost of the traditional up40
40
grade at 15.5 cents/kWh, with the
30
30
20
20
feeders in normal configuration. To
10
10
deliver the same deferral benefit and
0
0
retain operational flexibility, more
DERs are required, resulting in a
levelized cost of 59.2 cents/kWh
of load growth. The "waterfall"
portrayal shows the contribution of
(a)
(b)
DER credits to the overall cost.
Because distribution planners
figure 11. The cost to meet load growth (radial): (a) a traditional utility solution and
regularly reconfigure the sys- (b) a DER solution with high customer adoption.
tem due to load growth changes,
system maintenance, and system
While customer adoption of DERs, specifically PVs,
contingencies, comparing these two DER alternative cases
illustrates two important findings: 1) future operational flex- would not reasonably reach hosting capacity in the first year
ibility could be limited if the full impact of employing DERs of this study, some customer adoption will occur over the
as an alternative to traditional utility system resources is not ten-year study period. Comparing the two cases, zero with
accurately considered and 2) reconfiguration may change the high-adoption rates, provides bounding conditions for what
location of load and DERs with respect to a system viola- might actually occur. Under the assumptions of this study,
tion and, subsequently, the effectiveness of DERs to provide the levelized cost to defer traditional investment using strategically located DERs could therefore range from 22.2 cents/
deferral benefits.
As a bookend to the SCE normal/reconfigured cases, kWh for the high-adoption case to 41.1 cents/kWh of load
a high-adoption case was considered assuming customer- growth for the zero-adoption, normal configuration. This
connected PVs was already installed on the feeder system finding points to the importance and value of better foreequaling, but not exceeding the area feeders' hosting capaci- casting methods capable of characterizing both customer
ties. An incremental amount of strategic DERs was then inclination to adopt various DERs technologies as well as
employed to defer the needed upgrades. Several important how likely they are to apply such technologies to support
system capacity needs.
assumptions were used for this analysis.
1) Since the interconnected PVs were already at the feeder hosting capacity, no additional PVs were included in The Impact of System Topology
the incremental, strategic DER portfolio to avoid viola- on Locational Sensitivity
tion of system thermal, protection, or voltage limits.
The effectiveness of DERs to provide deferral benefits is
2) The subsequent DER portfolio considered for the in- highly dependent upon the location of the DERs relative to
cremental analysis was composed of energy storage, the system constraint, and these considerations vary by the
energy efficiency, and demand response measures, topology of the system. The location of projected system
proportioned to account for the removal of PVs.
violations (due to load growth) needing remediation and the
3) The DER portfolio placement was centralized at loca- load points where DERs can be installed to alleviate them
tion 1, near the feeder head, to allow direct compari- are key drivers to how much DERs are required and hence
son with the scenario 1 analysis.
the economics of DERs as a system asset.
4) To align with the system capacity needs, all of the
Network systems are characterized by complex and mul"customer-adopted" PVs and strategic DERs was in- tidirectional power flows, so the effect of DERs located
stalled and available in year one.
electrically "close" to a violation may become dispersed. In
The results of this analysis are illustrated in Figure 11. As some cases, dispersion is so significant that the DERs may
expected, the presence of customer-connected PVs produces only deliver a fraction of their nameplate capacity toward
a substantially more cost-effective outcome for the incre- mitigating a violation. As shown in Figure 12, lesser violamental, strategic DERs. The levelized cost of the incremen- tions on the Con Edison network could be resolved by plactal DERs needed, in addition to the existing PVs, to defer ing DERs on load nodes adjacent to the violation, so the
the upgrade was 22.2 cents/kWh, substantially less than the ratio of the required DER capacity relative to the violation
zero-adoption case.
was approximately 2:1 or lower. Greater violations required
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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2017