Launched by the California Independent System Operator (CAISO) in 2014 in partnership with PacifiCorp, the Western Energy Imbalance Market (WEIM) is a state-of-the-art real-time grid management system.
So how does the Western Energy Imbalance Market work? Let’s dive in.
A collaborative energy imbalance market
The concept behind an energy imbalance market is not unique. All Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) manage their day-ahead and real-time markets. What makes the WEIM special is that CAISO has opened it to entities outside of its ISO territory. This action is a first for the U.S.
The WEIM is an energy-only market that leverages resource diversity across several Western states, including California, Oregon, Washington, Utah, Idaho, and Wyoming. Nearly 25 utilities participate, or are planning to participate, in the WEIM.
Members determine how much of their transmission and generation assets will participate in the market, allowing them to maintain compliance responsibilities.
The organization, which has a five-member governing body comprising regional stakeholders, predicts it will serve 79% of the Western Electricity Coordinating Council’s total load sometime this year.
How WEIM works
The WEIM enables energy transfers between balancing areas, allowing participants to automatically buy and sell lower-cost electricity near the time it’s consumed. If a participant needs to meet an immediate power demand, the WEIM automatically finds and delivers the lowest-cost electricity.
At the same time, the WEIM gives participants real-time visibility into surrounding electric grids and an improved ability to balance fluctuations in supply and demand.
Integration of renewables
The WEIM supports the development of a modern sustainable grid by efficiently integrating excess renewable energy resources.
Renewable energy is typically the cheapest energy source, but weather conditions and time of day dictate wind and solar generation. This inherent intermittency means that during peak production hours, a local utility may be unable to use all the renewable power it generates. Rather than curtailing renewable generation by turning those units off, WEIM makes that excess, lower-cost clean power available to participants across the region.
For example, if one member has excess solar energy, the WEIM can deliver it to another member with higher demand or is producing less renewable energy due to unfavorable weather conditions. The collaborative system leverages the region’s geographic diversity; by expanding the renewable energy generation footprint, the WEIM makes the entire system more flexible and minimizes the impact of renewable generation gaps.
Benefits of energy imbalance markets
The Western Energy Imbalance Market has many benefits for its participants. Here are a few:
Reduced costs for participants — As noted above, WEIM members have access to the lowest-cost energy available when needed. Consumers can also benefit from the lower cost of electricity. The WEIM claims to have generated more than $2 billion in gross economic benefits for its participants since its launch.
Reduced carbon emissions — As mentioned earlier, the WEIM optimizes using excess renewables to meet demand. The organization claims that since its inception, it’s used 1.6 million MWh of renewable energy that would have otherwise been wasted or not generated in the first place.
WEIM also claims to have reduced greenhouse gas emissions by 712,270 metric tons since its launch, leading to a cleaner, more sustainable electric grid.
Enhanced electric reliability — The increased coordination between WEIM participants helps improve grid reliability during severe weather events and other emergencies. It also reduces the need for emergency assistance when a portion of the grid is stressed.
Learn how our US ISO Market software can help you automate and optimize your operations as you enter the WEIM.
