Oahu Wind Integration Study - Hawaii Natural Energy Institute ...

4.0 Background
In 2009 the General Electric Company, the Hawaiian Electric Company (HECO) and the Hawaii
Natural Energy Institute (HNEI) jointly developed power system models of the Oahu system to
assess forward-looking scenarios of plausible expansions to the generation mix on the island,
with a primary focus on wind plant installations. These models were developed and results
validated against 2007 historical data. The models were approved by the project team for the
subsequent phase of the study. In this subsequent phase of the study, GE assembled a baseline
model of the power system for 2014 (the future year of study) that included new generating
units, updated operating rules and forecasted system load, unit maintenance schedule, fuel prices,
etc. In this report, GE will highlight the results of the scenario analysis effort.
In Phase 1 of the study, models of the HECO system were developed, calibrated and validated
against actual system conditions. The model consisted of three specific simulation tools: the
production cost modeling tool, the transient stability dynamic model and a long-term dynamic
model, which included a representation of HECO’s Automatic Generation Control (AGC). The
production cost model considered the dispatch and constraints of all generation on an hourly
basis and provided outputs such as emissions, electricity production by unit, fossil fuel
consumption, and variable cost of production. The transient stability dynamic model considered
shorter timescale contingency events (sub-hourly) and characterized the system’s ability to
respond to these events. The long-term dynamic model considered critical wind variability event
over less than one hour and characterized the system’s ability to respond to these types of events.
The dynamic modeling tools were necessary to determine the impact of decisions made in the
longer timescales (production model) on the overall system operability. Statistical analyses tools
were developed to identify wind and load variability events, which were examined in greater
detail in this study.
The production cost model was developed to: (1) assess the variable cost of production (and its
breakdown in terms of O&M, fuel, and start-up cost), (2) estimate the amount of wind and solar
power curtailed, (3) quantify the overall system heat rate, and (4) describe the unit commitment
and dispatch for each scenario. The production cost modeling tool (GE MAPS TM ) curtails wind
and/or solar power when the units on-line cannot be backed down any further without violating
their minimum power output and down-reserve requirement. Further, the production cost tool is
used to initiate the dynamic model developed in GE PSLF TM , which is a tool for assessing
dynamic stability of the power system. A model of the HECO Automatic Generation Control
(AGC) was developed for the project in GE PSLF TM and was used to assess the unit performance
and system frequency impact of the wind variability for specific events on the system.
Significant interaction with the HECO and GE teams resulted in the development of a very highresolution
power system model for the island of Oahu. The purpose of this modeling and
analysis effort was to provide a Baseline measure of power system performance. This Baseline
model is used as a reference point for infrastructure evolution scenarios that explores alternative
energy futures for HECO.
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