Multiple RTOs in an interconnected region and Resolution of Seams Issues
The FERC has held many technical conferences on interregional coordination
amongst Regional Transmission Organizations covering a number of interregional
issues, which must be addressed in heterogeneous markets in the context of
institutional, and physical grid that exists within an interconnected region.
These issues include:
- Coordination of the
definitions of and requirements for various ancillary services that are
used in the management of the transmission grid; and
- Coordination of the scheduling
practices that govern the flows of energy and payments for energy between
the various control areas and transmission regions of the transmission
The second issue involves the scheduling practices required for reliable and
safe use of various transmission facilities taking into account the charges for
the use of the transmission facility that reflects the real costs of
transmission facility use, making sure it is sufficient to pay for the
maintenance, and provides appropriate incentives for the expansion of
transmission facilities. It should also not over charge some facilities to pay
for other transmission facilities within the grid.
The issues involved are often called “seams” issues because while there may
be alternative workable solutions in various regions of the grid, efficient
operation of the entire grid requires coordination at the regional borders, or
seams between the physical properties of the transmission grid, and the RTO’s
grid operation protocols.
The interaction of market rules and institutions with the physical
properties of the grid may be simulated with sophisticated computer programs
that include realistic representation of the behavior of market participants
and can accurately model the physical transmission grid. These models can show
the outcomes under an ideal set of market rules and institutions, which produce
the least-cost mix of generation that is consistent with the physical
requirements of grid operations. Alternative market rules can also be
simulated, and the results are compared with the ideal outcome of the market
models. Such an approach allows objective evaluation of different proposed
resolutions of seams issues.
The UPLAN Network Power Model, developed by LCG Consulting, supports such
simulation. It integrates a Nash model of profit-seeking generation owners with
a state-of-the-art A/C Optimal Power Flow model, to allow simulation of both a
minimum-cost security-constrained unit commitment and security-constrained
economic dispatches. It also allows representing the most important seams
issues related to sharing of regional resources for energy , reliability and
transmission across the whole region. The use of such models is an essential part
of diligent efforts to resolve the RTO seams issues and to optimize the
operations of RTOs.
Figure1. RTO 1 and
RTO 2 and interregional coordination.
To achieve the stated objective, UPLAN simultaneously
optimizes the operation of all the RTOs within the grid by modeling the
interconnected region while maintaining the individual operation protocol of
each RTO and accurately representing the Seams protocol of interactions amongst
the RTOs. In practical terms, the representation of inter-regional issues
mainly involves the modeling of exports/imports, network constraint, inter- and
intra-regional congestion management, and operation of phase shifters under
alternative transmission tariff arrangements.
Focusing attention on any particular RTO while ignoring or
reducing the impact of other RTOs severely misestimates the inter-regional
issues such as import/export profile, sharing of ancillary services and
reserve, as well as operation of hydro generators. Attempts to model RTOs in
isolation with minimum surrounding network interaction have not produced