BOOM! at Xcel’s Black Dog plant

September 22nd, 2010

An “ignition event” in the coal hopper, more commonly called an explosion and fire… Three firefighters on the scene were injured when it blew after they arrived.

This’ll be old news, but I’ve been incommunicado for a while, lost in the mountains of the Northwest, where there is no cell, no internet… what a concept!

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Photo by Bill Klotz, Finance & Commerce (Fair Use!)

An interesting quote:

“I would say it’s pretty significant,” said Behnken, gesturing toward the Black Dog plant from a nearby park. Though reporters were not allowed closer access to the plant, it was apparent from a distance that the explosion’s force far exceeded initial references to it as a small explosion in a coal bin.

Here’s some video from KARE 11 with shots of the exterior damage:

In the St. Paul Pioneer Press:

3 firefighters hurt in blast at Xcel Energy coal plant in Burnsville

Workers noticed smoldering coal bin

By Emily Cutts and Deepta Holalkere
Pioneer Press
Updated: 09/21/2010 11:47:43 PM CDT

Three Burnsville firefighters were injured Tuesday morning at a power plant fire and explosion that shook local residents out of bed.

The fire started in a smoldering coal bin at Xcel Energy’s Black Dog power plant in Burnsville, the company said. As fire crews tried to extinguish the flames, a blast in the bin rocked the plant.

Two of the firefighters were treated at the scene for minor burns and returned to fighting the fire. A third was taken to Regions Hospital in St. Paul with a leg injury, said Burnsville police Sgt. Jef Behnken.

“I heard a boom and then a bigger boom,” said Nancy Caneff, who lives nearby. Caneff was in bed when the blasts — the second strong enough to shake her bed — happened.

Firefighters put out two relatively small fires at the plant by 2 p.m. Tuesday but remained on site through the afternoon to handle hot spots, Xcel spokesman Tom Hoen said.

The 538-megawatt plant, which produces enough electricity to supply 400,000 households, has been shut down while the Burnsville Fire Department and Xcel Energy investigate the cause of the explosion, utility spokeswoman Patti Nystuen said.

The Minneapolis-based utility does not anticipate supply problems during the shutdown, she said.

Burnsville firefighters were called to the plant, on the Minnesota River at 1410 Black Dog Road E., at 7:25 a.m. after Xcel workers noticed a coal bin smoldering, Nystuen said.

Coal dust is highly combustible so Xcel workers water a plant’s stored coal frequently and monitor it, Nystuen said. Workers are also trained to deal with small fires.

Xcel workers shut down coal-fired boilers near the explosion Tuesday as a precaution. A natural-gas boiler was already offline for maintenance.

At the time of the explosion, 44 Xcel workers, 24 contractors and 17 construction workers were on site, Hoen said.

The Black Dog plant, built in the 1950s, has not had an explosion or similar incident in the past 20 years, he said.

However, in March 1989, the plant had to shut down after a line carrying lubricating oil for one of the plant’s turbines ruptured, spilling oil that ignited. No injuries were reported in that incident.

Xcel has proposed closing Black Dog’s two remaining coal-fired boilers and converting them to modern and larger natural-gas units by 2016. The proposal is pending before the Minnesota Public Utilities Commission.

If approved, the project would resemble work Xcel has done in recent years at its two aging coal plants in St. Paul and Minneapolis.

The High Bridge plant in St. Paul and the Riverside plant in Minneapolis have been converted to cleaner-burning combined-cycle natural-gas plants as part of a metrowide effort to reduce harmful emissions, including carbon dioxide that has been tied to climate change.

The state is also served by Xcel’s largest coal plant — the massive 2,400-megawatt Sherco plant near Becker, 45 miles northwest of the Twin Cities — and two nuclear power plants.

“We’re grateful no Xcel employees were hurt,” Hoen said after Tuesday’s blast. “Now, it’s just a matter of assessing the damage and moving forward from there.”

And in Finance & Commerce:

Explosion rocks Xcel’s Energy’s Black Dog plant


Posted: 3:58 pm Tue, September 21, 2010

By Bob Geiger

A Tuesday morning explosion rocked Xcel Energy’s Black Dog electricity plant in Burnsville, blowing out some 200 feet of the plant’s west-facing wall.

The blast occurred near the coal-fired, 108-megawatt Unit 3 burner at Black Dog – exposing ceiling sprinklers that continued spraying water more than three hours after the 8:12 a.m. incident.

Tom Hoen, a spokesman for the Minneapolis-based utility, said the plant would remain off-line for several days as a cause for the blast is determined.

The down-time gives Xcel a chance to more fully assess damage to the 538-megawatt plant, which uses both coal and natural gas for fuel, and which has been mentioned as a target for total conversion to cleaner-burning natural gas in a 2010 resource plan submitted to the Minnesota Pollution Control Agency earlier this year.

Jef Behnken, a spokesman for the Burnsville Police Department, said three firefighters were injured, with two treated on-site and the remaining firefighter transferred to Regions Hospital in St. Paul. No Xcel workers were injured.

“I would say it’s pretty significant,” said Behnken, gesturing toward the Black Dog plant from a nearby park. Though reporters were not allowed closer access to the plant, it was apparent from a distance that the explosion’s force far exceeded initial references to it as a small explosion in a coal bin.

Behnken said firefighters from Burnsville, Apple Valley and Eagan were called to the site after the explosion, which was felt by some homeowners south of the plant but caused no interruption of power supply.

Hoen said Xcel is buying power from other sources for as long as the plant is shut down.

He said Black Dog plant workers noticed smoldering fuel in a coal hopper inside the plant shortly after 7 a.m. Tuesday, and notified Burnsville authorities, who were on the scene when the blast occurred.

By noon, firefighters had extinguished most of the fire, and were extinguishing some spot fires on the plant’s roof, said Xcel spokeswoman Patti Nystuen.

Coal dust, a common cause of explosions in coal mines, could have caused the blast, particularly with a smoldering fire in progress. But neither Behnken nor Xcel would speculate on the cause.

At press time, Nystuen said that officials from Xcel and the Burnsville Fire Department had been joined by the federal Occupational Safety and Health Administration staff to pinpoint the blast’s origin.

“With a thorough investigation, the plant’s going to be down at least a couple of days,” she said.

Xcel’s plan for Black Dog is to convert the plant’s two coal-fired burners to a single combined-cycle unit fired by natural gas. That is similar to the conversion of two older Black Dog coal-fired units that reduced pollution from the plant.

Assuming the Black Dog plant conversion is completed, it is similar to the utility’s Riverside power plant in northwest Minneapolis, a former coal-fired plant whose generation increased to 511 megawatts after its conversion to national gas.

The plant was built in stages during the 1950s and 1960s, with the Unit 3 burner completed in 1955, Hoen said.

Posted by Carol A. Overland
Filed in Energy, Power Plants - includes Mesaba coal gasification
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