Hayward power plant restarts, cause of explosion still unknown

A power plant in Hayward has officially restarted after a massive explosion and fire in May that still remains a mystery.

The Russell City Energy Center got back up and running about 1:15 p.m. Thursday and is generating half the power it normally does, according to state regulators.

The California Energy Commission said the plant is needed to help supply power to the grid because of extreme heat conditions statewide.

"It is running in simple-cycle mode like a peaker power plant and is the last level to be called upon during extreme heat events," Lisa Buckley with the California Energy Commission said.

Simple-cycle mode means the plant is running without a highly-efficient steam turbine and instead is only relying on the two natural gas turbines to generate energy.

Calpine owns the plant where on May 27, the large steam turbine blasted apart and sent heavy chunks of hot metal catapulting up to 1,200 feet away. No one was hurt and the cause is still not known.

Commissioners approved Calpine’s restart plan last month, despite opposition from the City of Hayward.

The Hayward city manager and the fire chief were both notified about the plant becoming operational Thursday and said in a business meeting earlier this week with state regulators that communications between Calpine and other stakeholders had improved since the May incident.

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Brooks Jarosz is an investigative reporter for KTVU. Email him at brooks.jarosz@fox.com and follow him on Facebook and Twitter: @BrooksKTVU