By Tim McLaughlin
BOSTON, Jan 24 (Reuters) - U.S. electric grid operators on Saturday stepped up precautions to avoid power shortfalls and rotating blackouts as frigid weather affecting nearly half the country's population ramped up stress on their operations.
The PJM Interconnection - the largest U.S. regional grid which serves 67 million people in the East and Mid-Atlantic - reported temporary spikes in spot wholesale electricity prices to nearly $3,000 per megawatt hour on Saturday morning from
earlier levels of less than $200 per MWh.
Prices soared as stormy weather and temperatures hovering around 0 degrees Fahrenheit (-18 C) pushed up electricity demand and prompted some operators to shut in natural gas production in key basins, while grid companies also faced constraints on gas pipeline supply.
Faced with constricted gas supplies, regional grid operators in the U.S. are asking producers such as coal-fired power plants to boost their output, according to grid operations reports.
The Midcontinent Independent System Operator (MISO) called on power plants to maximize output and curtailed electricity exports in a territory that stretches across 15 states in the Midwest and South and Manitoba, Canada.
MISO's all-hands-on-deck emergency action is designed to avoid capacity shortfalls as some power plants are forced offline or reduce their output because of freezing temperatures, alerting utilities to be prepared to produce as much electricity as possible.
MISO spot wholesale electricity prices soared to nearly $500 per MWh in MISO's Minnesota hub, as the upper Midwest experienced transmission bottlenecks across high-voltage power lines. By contrast spot electricity prices in MISO's southern territory were less than $50 per MWh.
In New England, fuel oil generation kicked into high gear to help the six-state region's electric grid to conserve natural gas, its top fuel source.
Early Saturday, oil-fired generation accounted for 26% of the New England grid's output, compared with a typical level of about 1% or less, ISO New England's operations display showed. Natural gas accounted for 28% of the grid's generation output.
New England spot electricity prices were more than $300 per MWh, or about double the price on Friday.
(Reporting by Tim McLaughlin; Editing by Jan Harvey)
