S&P Global Market Intelligence presents the most read stories for the week ended Dec. 21.

1. After a decade of changes, SPP looks to modernize power market rules

The Southwest Power Pool is undertaking a year-long review of its governance, transmission cost allocation and planning philosophies to accommodate dramatic changes in the wholesale power market and electric utility industry over the past decade.

2. PJM CEO: Repeated questions from politicians prompted mass retirements study

PJM Interconnection, which coordinates the movement of electricity in 13 mid-Atlantic and Midwestern states plus Washington, D.C., released the full version of its extreme generation retirements and fuel security scenario study Dec. 17.

3. PG&E says it made leadership changes over records problems before Calif. probe

Pacific Gas and Electric Co. said it changed corporate leadership in response to internal concerns about complying with key gas safety rules and keeping accurate related records, although the utility has not elaborated on the nature of those personnel changes.

4. SC regulators defend decision to OK Dominion purchase of SCANA

While several South Carolina regulators admitted that they were conflicted about the decision, they all agreed that approving Dominion Energy Inc.'s offer to acquire SCANA Corp. was necessary to provide "certainty" for the embattled utility, its ratepayers and the state.

5. Ark. AG warns of rate hikes from Entergy coal retirement settlement

Arkansas' attorney general criticized a settlement between Entergy Arkansas LLC and environmentalists, asking a federal judge to intervene on behalf of ratepayers to prevent a rate increase that could stem from future coal retirements.