Dive Brief:

• The California Independent System Operator’s Board last week approved the Distributed Energy Resource Provider Draft Final Proposal, which will allow aggregators of distributed energy resources (DERs) to sell into the ISO’s marketplace. It will be the first U.S. grid operator buy aggregated DERs.
• Companies including utilities will be able to purchase and consolidate the output of rooftop solar systems, batteries, and plug-in electric vehicles from multiple homes and commercial power systems to a bundle baseline capacity that can sold into the ISO electricity market.
• Access to the market is expected to eventually allow DERS to have a greater role in meeting the state’s energy needs and mandates. It is seen as a critical advance in rooftop solar and solar plus storage system economics.

Dive Insight:

The ISO plan expands metering and telemetry, the grid operator’s communications and counting methods, and the technologies the grid operator will need to track and integrate the aggregated resources.

Because it would be too costly to have an ISO meter on every rooftop solar installation, the plan allows a scheduling coordinator to take administrative control of aggregated distributed energy accounts and meter them with any technology, including any online technology.

There are some 4,900 market pricing nodes (PNodes) on the ISO system and it is also divided into load aggregation points (LAPs) that follow the territories of the state’s three investor-owned utilities. They are subdivided into sub-LAPs. Multiple small resources can be aggregated across multiple PNodes but they can only be in one sub-LAP.

Within that sub-LAP, aggregations can span multiple PNodes if they are the same type of resource — either sending electricity to the grid or receiving it. Resources like solar-plus-storage that both send electricity to the grid and absorb it would make the process unmanageable for the ISO at present.