ISO-NE is digging into the details on how it plans to measure the limitations of gas generators in its new capacity accreditation process.

At this week’s NEPOOL Markets Committee meeting, the grid operator continued laying out its proposed methods for de-rating gas resources in the winter, when they may have challenges getting fuel.

Under ISO-NE’s proposed framework, the capacity qualification process would include a determination of gas plants’ firm and non-firm capacities for the December to February period each year. The RTO is developing firm fuel requirements that the generators would have to meet in order to get a firm capacity rating.

And there would be a new way to rate what ISO-NE is calling “operationally limited resources,” which are those that are expected to be unable to get gas at all and would in turn be assigned zero qualified capacity for the winter period.

“Operationally limited resources are unlikely to receive gas on many cold days, let alone days when minimal non-firm gas is available for generators,” said Alexander Mattfolk, a consultant with Levitan & Associates, which is helping ISO-NE develop the new framework.

These decisions will be backed by new pipeline and LNG forecasts, which Levitan is also helping to develop.

Other MC Business

Also at the MC meeting this week, ISO-NE continued its explanation of its proposed day-ahead ancillary services market, which is intended to fill energy gaps in the day-ahead market and procure reserves that can start up quickly, in 10 or 30 minutes.

The project borrows heavily from ISO-NE’s previous Energy Security Improvements project, which ultimately failed at FERC.

In addition to reiterating the basics of the market, which includes a new constraint called the forecast energy requirement and a new product called the energy imbalance reserve, ISO-NE shared its plan for forecasting real-time LMPs.

The grid operator is planning to use a “Gaussian Mixture Model,” into which it will plug the day-ahead market load forecast, 24-hour lagged LMPs, the prices of gas and oil, weather forecasts and historical LMP data.

ISO-NE also continued its discussion of updates to the Inventoried Energy Program.