IEEE Power & Energy Magazine - September/October 2017 - 47

Given the wide array of services that ESSs can provide, various
agents-including generators, consumers, and network owners and
operators-have an interest in owning and operating them.
ing the constraints of limited energy storage resources. Other
United States
FERC's notice of proposed rule making (NOPR) on storage resources such as demand response may also participate in the
participation in markets takes a different approach, suggest- CAISO DAM as an NGR.
Resources participating as NGRs are required to submit
ing the implementation of a participation model for electricity storage resources based on bidding parameters that allow additional parameters in their bids, including
storage operators to reflect the physical and operational
✔✔ upper/lower charge limits
characteristics of their resources. Specifically, FERC sug✔✔ SoC subject to a charge/discharge efficiency rate.
gests that the following bidding parameters be added:
Furthermore, NGRs may choose to self-manage their SoC
and energy limits.
✔✔ state of charge (SoC)
In NYISO, according to the open-access transmission
✔✔ upper/lower charge limits
tariff, ESSs may participate in the DAM as energy limited
✔✔ maximum/minimum energy charge rates
resources (ELRs). NYISO defines ELR as "capacity resources
✔✔ minimum/maximum charge time
that due to environmental restrictions on operations, cyclical
✔✔ minimum/maximum run time.
With these bid parameters, FERC suggests that the ISOs requirements, such as the need to recharge or refill, or other
could more efficiently optimize the dispatch. FERC also pro- non-economic reasons, are unable to operate continuously on
poses that storage agents be given the choice to self-manage a daily basis, but are able to operate for at least four consecutheir SoC and other bidding parameters through their own tive hours each day."
To be eligible to provide energy, the resource must be
bidding strategies. The NOPR argues that, although a more
efficient dispatch is achieved when the device is in the sys- able to contribute at least 1 MW of grid injection for at least
tem operator's hands, self-managing affords ESS owners the 4 h. As a result, a resource with 4 MWh of energy capacity can, at maximum, bid 1 MW of capacity into the DAM.
possibility of providing multiple s- ervices.
Nevertheless, for the time being, the participation of energy Moreover, ELRs shall bid a normal upper operating limit.
storage in energy markets remains limited. For instance, the SoC management for ELRs is not available but is expected to
Southwest Power Pool (SPP) has no tariff language on electric be addressed as part of the more comprehensive distributed
storage. MISO has defined a resource category for electric stor- energy resource (DER) road map.
In PJM, ESSs connected directly to transmission or
age resources (ESRs) but, for the time being, allows only for the
provision of regulating reserve. [MISO is currently involved in distribution networks participate in the DAM as generation
a stakeholder process "exploring the potential creation of a new resources, whereas storage resources located behind the meter
ESR category that, unlike a Stored Energy Resource ("SER"), participate as demand-side resources. Pumped hydro storage
would not be limited to the provision of Regulating Service" resources may choose whether to self-schedule their unit or be
(FERC Docket EL 17-8-000)-as required by the FERC dispatched by PJM. Units that choose the latter must present
NOPR and a separate FERC order following complaints a number of pumped-hydro-specific parameters. However
from an stakeholder (Indianapolis
Power and Light), which owns a
20-MW battery.]
Exclusive Block Order
CAISO has introduced the nongenerator resource (NGR) participation model to promote the market
Linked Block Order 3
integration of ESSs. NGRs are
Linked Block Order 2
assumed to have a continuous operating range from a negative to
Linked Block Order 1
a positive power output-that is,
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
NGRs can operate continuously by
(Hours)
either consuming or providing enPurchase Order
Selling Order
ergy. As a result, functionally the
NGR is particularly well suited, but
not limited, to adequately represent- figure 2. An example of an exclusive block order.
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