How Much Renewable Energy Can a Power Transmission System Accommodate?

A new EPRI tool can help utilities answer this question.

Transmission planning increasingly is driven by needs associated with grid-connected variable renewable energy resources. Transmission infrastructure, particularly in remote areas suitable for large wind and solar capacity, may nevertheless be limited with respect to the amount of new generation that can be accommodated without exceeding thermal or voltage limits.

EPRI’s Transmission Hosting Capacity Tool builds on similar EPRI software for distribution systems. It enables utilities to screen various scenarios for generation, load, dispatch, and grid conditions and to gauge where and how new generation could impact the system’s thermal and voltage performance. The tool can inform utility decisions on grid upgrades and optimal locations for renewables, although it’s not intended to replace detailed system impact studies necessary for investment decisions.

In 2018, EPRI and Salt River Project (SRP) tested the tool on the utility’s transmission system. They determined that it provides a useful “first cut” in assessing the maximum renewable generation that can be accommodated without system upgrades. By automating the analysis, the tool enabled substantial savings in work hours.

“EPRI’s newly developed Transmission Hosting Capacity Tool has allowed SRP to easily understand how the development of solar photovoltaic resources will impact transmission system reliability,” said Justin Lee, SRP manager of transmission system planning. “The work done by this team allowed SRP to demonstrate the tool in a real-world environment, showing how this new automatic assessment capability can benefit system planning.”

EPRI plans to test the tool with other utilities to develop its application to larger systems.

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