Western Energy Imbalance Market

Western Energy Imbalance Market
Name	Western Energy Imbalance Market
Abbreviation	WEIM
Founded	2014 (piloted)
Region	Western United States, Western Canada, Baja California
Operator	California Independent System Operator, later Midcontinent Independent System Operator involvement
Participants	Multiple investor-owned utilitys, public utilitys, municipal utilitys, electric cooperatives

Western Energy Imbalance Market

The Western Energy Imbalance Market is a real-time wholesale electricity market serving much of the Western Interconnection across the United States, Canada, and Mexico. It operates as a short-term balancing market to match supply and demand, provide ancillary services, and coordinate dispatch among utilities such as Pacific Gas and Electric Company, Southern California Edison, Bonneville Power Administration, Los Angeles Department of Water and Power, and BC Hydro. Started as a pilot and evolving through enrollment phases, it intersects with entities like California Public Utilities Commission, Federal Energy Regulatory Commission, North American Electric Reliability Corporation, Western Electricity Coordinating Council, California Independent System Operator and later arrangements with Midcontinent Independent System Operator.

History and development

The market originated from initiatives by California Independent System Operator to improve efficiency following challenges identified after events like the California electricity crisis and studies by Energy and Environmental Economics, Inc. and National Renewable Energy Laboratory. Pilot phases began in 2014 with participation by utilities including Sacramento Municipal Utility District and Portland General Electric. Subsequent expansion rounds involved enrollment by Public Service Company of New Mexico, Nevada Power Company (NV Energy), Arizona Public Service, and San Diego Gas & Electric. Key regulatory milestones involved filings before Federal Energy Regulatory Commission and approvals influenced by precedents from PJM Interconnection and Electric Reliability Council of Texas. Technical demonstrations referenced models from California Energy Commission and research by Lawrence Berkeley National Laboratory, with governance adaptations informed by North American Electric Reliability Corporation standards.

Governance and participating entities

Governance originally rested with California Independent System Operator under oversight from FERC and coordination with regional bodies like Western Electricity Coordinating Council and North American Electric Reliability Corporation. Participating utilities span investor-owned utilitys (e.g., Pacific Gas and Electric Company, Arizona Public Service), public utility districts (e.g., Bonneville Power Administration), municipal systems such as Los Angeles Department of Water and Power and City of Seattle, and electric cooperatives. Independent entities such as Independent System Operators and regional transmission organizations exemplified by PJM Interconnection, ISO New England, and Midcontinent Independent System Operator served as reference models. Regulatory stakeholders included California Public Utilities Commission, Nevada Public Utilities Commission, and provincial authorities like British Columbia Utilities Commission.

Market design and operation

The market executes five-minute and hourly dispatch to settle energy imbalances using centralized dispatch optimization similar to algorithms employed by PJM Interconnection and ISO New England. It integrates telemetry and state estimation techniques from North American Electric Reliability Corporation compliance models and uses transmission constraint models akin to analyses by Lawrence Berkeley National Laboratory. Participant bids and offers from entities such as Southern California Edison, San Diego Gas & Electric, and NV Energy feed into security-constrained economic dispatch routines implemented within California Independent System Operator platforms. Congestion management, ancillary services procurement, and loss allocation follow frameworks inspired by FERC orders and market rules used by New York Independent System Operator.

Pricing, settlement, and financial mechanisms

Prices in the market are determined through marginal-cost pricing in locational marginal pricing fashion comparable to PJM Interconnection and ISO New England practices, producing locational price signals for nodes served by participants like Portland General Electric and Seattle City Light. Settlement systems reconcile deviations against day-ahead markets operated by entities such as California Independent System Operator where applicable, and financial transmission rights concepts take cues from PJM Interconnection and NYISO instruments. Billing and credit arrangements were structured with input from FERC filings and financial oversight by state commissions including California Public Utilities Commission and Nevada Public Utilities Commission, and coordination with balancing authorities such as Bonneville Power Administration.

Integration with regional grids and renewables

Integration efforts focused on accommodating high penetrations of renewable energy resources like utility-scale solar power farms in California and Arizona, wind projects in Idaho and Wyoming, and hydroelectric facilities operated by Bonneville Power Administration and BC Hydro. The market enhanced dispatch coordination across the Western Interconnection and enabled better utilization of resources across time zones involving entities like Arizona Public Service and PacifiCorp. Grid reliability interactions referenced standards from North American Electric Reliability Corporation and operational practices from California Independent System Operator to balance variability from projects developed by firms such as First Solar and NextEra Energy.

Impacts and evaluations

Independent analyses by Lawrence Berkeley National Laboratory, National Renewable Energy Laboratory, and consulting firms like The Brattle Group reported cost savings, reduced dispatch inefficiencies, and decreased renewable curtailment. Participants including Pacific Gas and Electric Company, NV Energy, and Sacramento Municipal Utility District cited operational benefits, while state regulators including California Public Utilities Commission documented impacts on retail rates and reliability metrics. Comparative studies referenced markets managed by PJM Interconnection, Midcontinent Independent System Operator, and Electric Reliability Council of Texas to contextualize outcomes.

Criticisms and challenges

Critiques from municipal utilities such as Los Angeles Department of Water and Power and some public utility stakeholders highlighted concerns about governance concentration under California Independent System Operator and the implications for transmission planning seen in proceedings at Federal Energy Regulatory Commission. Questions were raised about cost allocation involving entities like Public Service Company of New Mexico and Bonneville Power Administration, and about integration with regional transmission planning processes led by Western Electricity Coordinating Council. Technical challenges included modeling of congestion and losses addressed in workshops with Lawrence Berkeley National Laboratory and National Renewable Energy Laboratory, while policy debates involved state regulators like Nevada Public Utilities Commission and California Public Utilities Commission regarding participation incentives.

Category:Electric power transmission in North America