August 11, 2015 | By Jaclyn Brandt

The Federal Energy Regulatory Commission (FERC) has approved an effort to help manage congestion on the Independent System Operator - New England (ISO-NE) grid -- by ruling on the renewables allowed on the system.

ISO-NE electric regions. Credit: FERC

ISO-NE's request said that because renewable output is variable, the integration of renewable resources in remote areas of their transmission system has caused increased congestion.

"Intermittent renewable resources such as wind are still a small part of the New England generating fleet, but they are increasing. Most wind plants are installed in remote areas of the region with transmission lines that were designed to deliver generation from relatively small, remote hydro generators, not to carry large amounts of generation," ISO-NE spokesperson Marcia Blomberg told FierceEnergy. "As a result, system operators have maintained reliability by, at times, manually curtailing the output in some local areas of wind and other plants that might otherwise overload these smaller transmission lines. The 'do not exceed' system, with automated signals, is expected to continue to maintain reliability while maximizing utilization of the limited transmission lines and improving the ability to use low-cost renewable resources, thereby improving economic efficiency."

 

Because of this, the approval would modify methods for wind and hydropower resources on the ISO's grid. With the approval, the ISO will be able to upgrade from a manual dispatch to electronic management.

"Intermittent power resources, which do not have direct control over their net power output, are not currently electronically dispatchable and must be manually curtailed to manage congestion," ISO-NE explained. "This manual process is inefficient, as the curtailment and thus, the congestion, are not reflected in real-time prices."

The ISO said that there is a "mismatch of economic signals and reliability requirements." Because renewables require manual operation, low-cost resources should continue operating to ensure reliability on the grid.

Because of this, ISO-NE was proposing a modified electronic dispatch method, called DNE Dispatch Points, for certain wind and hydro resources on their grid. Those resources are classified as Intermittent Power Resources under the ISO's own rules -- and are larger than 5 megawatts (MW).

"We agree with ISO-NE that these changes will improve price formation, particularly in areas that have a high penetration of renewable resources and limited transmission capacity; and system reliability, because of the reduced reliance on manual curtailments," FERC explained. "Further, these proposed changes will allow for better alignment between price signals and operational requirements."

In their ruling, FERC also rejected the idea that all resources, even renewable, had equal opportunity to be dispatched.

"We are not persuaded by RENEW's and SunEdison's claims that it is necessary to expand the proposed dispatchability requirements beyond resources addressed in the instant filing," the commission said.

FERC said it would leave the decision to the system operator, and said that "by allowing wind and hydro resources to be dispatched on an economic basis, the DNE Dispatch Changes will minimize the need to use manual curtailment processes for those resources and should allow for both more efficient economic outcomes and better system reliability."

ISO-NE had said that by reducing manual curtailment, they would maximize use of current transmission resources and intermittent resources. FERC explained that "ISO-NE states that this is because the restrictive nature of manual curtailment forces system operators to be more conservative than they would be otherwise. In addition, the new dispatch method should align long term locational price signals with actual economic conditions."

ISO-NE's request did not include solar because "the lack of a need to dispatch solar resources to ensure reliable operations and ISO-NE's current inability to develop accurate, short-term, plant-specific forecasts for solar resources. ISO-NE explains that the technology has not yet been developed to make plant-specific forecasts feasible."

The proposed tariff revisions are set to go into effect in April 2016, which will give ISO-NE time "to inform and train smaller hydro resources, as they prepare for the changes."

FERC has directed ISO-NE to submit a compliance filing within 30 days. Blomberg said they plan to file by Aug. 21.

For more:
- view these documents

 

© 2015 FierceMarkets, a division of Questex, LLC. All rights reserved.

http://www.fierceenergy.com/story/ferc-agrees-renewables-cause-congestion-iso-ne-grid/2015-08-11