MISO Energy Storage Study Phase 1 Report - Utility Wind ...

EXECUTIVE SUMMARY
Introduction
MISO is a non-profit member based organization regulated by the federal energy regulatory
commission (FERC). As a Regional Transmission Organization (RTO), MISO provides
electricity consumers in 13 states with regional grid management and open access to
transmission facilities through a tariff closely regulated by FERC.
State legislated renewable portfolio standards (RPS) within the MISO footprint in Montana,
Minnesota, Wisconsin, Iowa, Missouri, Illinois, Michigan, Ohio, and Pennsylvania require
varying percentages of electrical energy be met from renewable energy resources starting in
2010. These mandates resulted in initiatives to integrate renewable energy generation, primarily
from wind, into the MISO market. Wind resources now account for 6 percent of installed
capacity (approximately 9.2 GW) and 3.5 percent of generation, producing hourly capacity up to
6.7 GW 1 . Economic electricity generation from wind typically occurs some distance from load
centers, requiring new transmission be constructed to reach consumers. Typical wind patterns
produce higher energy at times when electricity demand is low. Wind generation is also variable
and has to be carefully balanced with conventional resources in order to maintain system
reliability.
As significant variable generation resources are added to the transmission grid the system
complexities associated with balancing generation and demand increase. Greater flexibility is
required to maintain reliable service. In this circumstance, the role that energy storage plays in
systems planning becomes important. Long-term energy storage is attractive because it can be
used to shift electricity generated during low demand periods for use during peak demand. Shortterm
energy storage also has potential value in providing a frequency regulating resource to
maintain system stability. MISO currently accommodates long-term storage resources in its
markets in the form of pumped hydro storage (PHS). Short-term storage is accommodated as a
regulating reserve resource in the MISO ancillary services market (ASM).
To better understand the role of energy storage, the Energy Storage Study was initiated by MISO
to model several hypotheses around battery, compressed air, and pumped hydro energy storage
technologies. The study explores reliability, market, and planning benefits that storage
technologies could potentially provide. The study seeks to determine economic potential for
storage technologies in MISO. It will estimate the price inflection point at which energy storage
may become economically feasible. Finally, the study will suggest potential MISO energy and
operating reserve markets enhancement products.
1 2010 MISO State of the Markets Market Monitor Report June 2011, Potomac Economics
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