[Fair Use: For Education and Research Purpose Only]

February 23, 2000

Power plant explosion

BY AL J. LAUKAITIS - ERIC GREGORY/ Lincoln Journal Star

Blast damage: An explosion Monday evening peeled back the walls and roof on the upper west side of Nebraska Public Power District's Sheldon Station power plant near Hallam. Coal dust apparently ignited as it was being loaded at the front end of one of two boilers at the plant. No one was injured.

HALLAM -- For the second time in less than two months, an explosion rocked Sheldon Station, a coal-fired power plant south of Lincoln. No employees were injured in the blast, which occurred about 5 p.m. Monday and created a large hole in the upper west side of the plant, said Dave Simon, spokesman for Nebraska Public Power District, the plant's owner.

NPPD officials downplayed the seriousness of the explosion, characterizing it as bigger than a "puff." However, Simon said it was loud enough to be heard by the plant manager, who went to investigate.

"Little fires like this are not uncommon," Simon said. "They do occur in coal plants." On Dec. 29, two NPPD employees plunged to their deaths after an explosion blew them out the door of a 100-foot fly ash silo. Killed were Duane Swoboda, 49, of Columbus and Terry Egger, 50, of Hallam. A third employee, Sidney Penner, 40, of Odell, sustained minor injuries.

After an investigation, NPPD said fly ash -- estimated at 1,500 degrees -- combined with coal particles and oxygen to cause the December blast. At the time, fly ash from the silo was being loaded into a truck for transport into a nearby pit.

Monday's explosion happened in a different area of the plant and was not related to the earlier one, Simon said in a phone interview from NPPD corporate headquarters in Columbus.

He said Monday's blast occurred on the ninth floor in a coal-handling system for Unit 2, one of two boilers for the plant. He said some coal dust apparently ignited as it was being loaded via a conveyor belt at the front end of the boiler. He said he did not know whether any workers were present at the time of the explosion.

"There are no plant operations that call for employees to be in that area," Simon said.

Station Manager Glen Baete said the explosion occurred above eight empty floors of storage bunkers, and no one was in the room when it occurred.

Most of the plant's approximately 80 employees and 30 to 35 special project workers had left when their shift ended at 4:30 p.m., Baete said. Those who remained were accounted for within 15 minutes, he said.

Baete said he knew of no witnesses who saw the blast, but several heard it. "It was a loud boom," he said.

Hallam volunteer firefighters responded to the explosion, but a sprinkler system extinguished the fire before they arrived. Simon said some paneling on the ninth floor was damaged.

Areas of smoldering dust kept fire crews working into late evening, Baete said. He did not know how many fire departments were keeping the situation under control, but Hallam, Hickman, Firth and Cortland volunteers were on the scene.

Unit 2, where the blast occurred, was shut down Monday night while the other boiler continued to operate. The two boilers can generate 225,000 kilowatts of electricity. Lincoln Electric System contracts for 30 percent of the power produced at Sheldon.

Asked whether there was a safety problem at the plant, Simon replied:

"We continue to spend money on the maintenance to comply with all the codes and operating procedures that industry meets nationwide. We continue to invest to ensure that we meet safety standards." Baete, who has been station manager since June 1998 and has worked at the plant since October 1976, said he would not comment on whether employees should have heightened safety concerns in the wake of the two explosions.

The cause of the accident was not known Monday night.

"We will be investigating to figure out the root cause and mitigate any possibility of it happening again," Simon said.

Al J. Laukaitis can be reached at 473-7243 or alaukaitis@journalstar.com.

Journal Star reporter Shane Anthony contributed to this story.

http://www.journalstar.com/stories/loc/sto2

-- Dee (T1Colt556@aol.com), February 23, 2000

Answers

Yea, Sheldon employees should have "increased safety concerns" as a result of two explosions in three months. This employee would find another job if my plant had had such a downturn in safety.

I suspect this plant is an "accident waiting to happen" as a result of lax "housekeeping." (Piles of smoldering dust?)

For a coal burning plant, housekeeping is the primary insurance against a claim against your life insurance. Most plant operators forget that a suspension of coal dust in the air that can barely be seen with the naked eye is a potential for an explosion. Coal dust/ air suspension burns similarly to a propane or natural gas fire.

One of the major maintenance faux pas in a coal powerplant is to use compressed air to "blow" coal dust off of interior surfaces. The dusting off creates a suspension in air and the static charge caused by the air jet creates the spark to send the cleaner to his final reward. In this case cleanliness *is* next to Godliness: right next to him in fact.

The best way to clean coal dust in appropriate areas is to use a water hose. A small "backpack" pressure sprayer with a soap solution helps act as a "wetting agent" and can be applied over a wide area before spraying with the hose.

I suspect the problems may be more fundamental than just lack of attention to housekeeping, however. More than likely deregulation has forced the plant manager to cut back on personnel and this is now having a deleterious effect on housekeeping and safety as well. The time frame of Mr. Baete's tenure would just about correspond to the duration necessary for conditions to reach "dangerous." Mr. Baete should know better.

The amazing fact is that personnel costs are probably less than 0.5 percent of the plant operating budget.

I hope the employees come out of their employment experience well compensated. They should since it's their lives at peril.

Best regards,

-- Joe (KEITH@neesnet.com), February 23, 2000.

Dee, I found this a very interesting article. Thank you.

Joe, your observations were very, very well put and knowledgable. Reminds me of the cautions associated with working around either dry fertilizer or in a grain elevator setting.

Coal plants are the most expensive power sources for a utility to run, right? If so, they are used to pick up large, marginal power requirements, and preferrably not on a permanent basis. My recollection is that diesel-power gensets are proliferating, but are usually capable of carrying only a small percentage of a normal coal plant's load.

What does a utility commonly do with a coal plant between periods of needing to run it up towards capacity? Idle it, keeping the boilers hot (if indeed boilers are used)? How long does it take to restart a cold coal plant? My recollection was that coal plants were fed a slurry. Is that not correct? Was trying to figure out where the 'piles of coal dust' came from - from grinding up the lumps into a wettable powder?

Joe, your observations about staffing levels certainly pass my smell test. Probably up to and including this plant manager. My concern is much more for the plant workers, and give that the senior workers have probably long been laid off, those left may not have much real appreciation for the dangers. Bet OSHA could go nuts in that place!

-- redeye in ohio (cannot@work.com), February 23, 2000.

Good input Joe and redeye.

-- Dee (T1Colt556@aol.com), February 23, 2000.

Actually, no. Coal fired power power is among the *cheapest* power going. That is, the fuel is among the cheapest on a "Btu per dollar" basis. What makes coal expensive is the plants are "maintenance intensive" and "environmental intensive" with a large capital investment for the fuel processing, precipitating, and "scrubbing" equipment required.

The Sheldon plant is likely a "mine mouth" western plant and may even burn "lignite" which is coal still in it's "formative" stage. This is an extremely cheap fuel source. (Actually lignite is a sub-coal only a step or two beyond peat from which all coals are formed.)

Nuclear Power until about 1988 was a "contender" in the fuel price race until the effects of Three Mile Island caught up with it. Since then, the realization of the hazards and the ever increasing regulation (probably deserved) has made nuclear power less and less cost effective. Nuclear fuel is still the best price fuel (most Btus per dollar) but the overheads of the nuclear industry now make it's use a difficult proposition at best to make money at.

Nuclear and coal plants seems to survive best when run at constant load, thus they carry the "base load," with other more costly generators being run to carry the "peaking" requirements.

Natural Gas fired gas turbine plants have been used in the past for "peak load" coverage.

A relative newcomer to the generation business is the "Combined Cycle" plant which uses a gas turbine coupled with a "waste heat boiler" which in turn drives a steam turbine. This utilizes the btu effect twice which allows a more complete conversion from thermal energy to electrical energy.

General Electric just announced a new gas turbine design which results in a combined cycle heat rate of 5560 Btu's per kilowatt hour. This is a plant thermal efficiency of 61 percent conversion which is a tremendous improvement over nuclear plants (15 percent thermal efficiency) and coal and oil fired plants (30-32 percent.)

The downside of combined cycle plants are that they primarily burn natural gas which historically has been the expensive fuel. Right now there is a "gas bubble" with depressed prices which make a combined cycle plant attractive to those in the business. With GE's new gas turbine, even a combined cycle plant will be able to compete in the "base load" market.

The story of electrical generation has been one of ever increasing efficiency, ever decreasing environmental effects, and ever increasing capital investment. The new "deregulated" electrical marketplace has spurred these improvements.

Some plant owners realize their "precarious" situation in a deregulated energy marketplace. Likely Sheldon may be among those who are less "profitable" than a more modern plant, and the ownership's answer is to "run it into the ground" and get their money out of it before it is overtaken by other more efficient and profitable plants.

Meanwhile, the newly separated "wires companies" still retain the attitudes of "WE'RE THE POWER COMPANY, SNORT, SNORT." It's likely to be that way for some time to come since as a society we can't afford to build "competing" wires on the electrical poles. Thus, there remains a need for a PUC and there will be the "entrenchment" and "excess fat" of a natural monopoly as there has been in the past. It just won't include the actual "energy source" now.

The public utilities have encouraged and applauded deregulation. It has released them from the "uncertainty" of building powerplants and having to compete with just *anyone* who might be able to do it better. Read "Who Owns the Sun" by Berman for a different look at deregulation issues. It's a bit of a tedious read but it says it like it is. (I think.)

Meanwhile the utilties are like a bank or an insurance company. They'll always make money. A secure return for a secure investment.

Is this wrong? I'm not sure. Do I like it. Not a bit.

Best regards,

-- Joe (KEITH@neesnet.com), February 23, 2000.

Joe,

Again, my apprecation for a quite informative response! This is getting to be a thread that I certainly will save off for future reference!

My presumption was that coal plants, per se, were the most costly in terms of total cost per kw generated. Your lignite-related observations tell me that, once again, 'per se' generalizations often over-simplify the issues.

Your observation that "the overheads of the nuclear industry now make it's use a difficult proposition at best to make money at" made me consider the question of to what degree that situation is an accounting or regulatory matter. I am presuming that most N-plants by now are well-depreciated, as are most all coal plants, with only new, e.g., pollution-control equipment capitalized.

So, nuclear and coal plants usually carry a utility's base load, with other types of sources, such as combined cycle plants, carrying peak load.

Your statements that "The downside of combined cycle plants are that they primarily burn natural gas which historically has been the expensive fuel. Right now there is a "gas bubble" with depressed prices" I found surprising in light of the other petroleum-related information that's been appearing daily on this site.

I realize that large users such as these plants will have long-term supply contracts, and that NG has been 'cheap' for a fair while. At the same time, NG is largely continentally-sourced, is it not? And NG supplies to, e.g., cogen plants, will be subject to interruptions when supply shortages/weather cause large homeowner demands.

Thus, (as a utility) were I evaluating investing in a cogen plant, unless I could burn something else in it, shouldn't I consider NG a somewhat questionable fuel type? And if, as the utility, I have to accept that a cogen plant may not be able to be run on NG during the coldest weather due to fuel supply interruptions, is that not a major factor to consider as I evaluate (as the utility) my whole mix of power production sources?

Again, thank you for offering an awful lot of very interesting information and for your time spent doing so! This place just continues to amaze me!

-- redeye in ohio (not@work.com), February 23, 2000.

to the top

-- Dee (T1Colt556@aol.com), February 23, 2000.

What you are getting at (our dependence upon a "singular fuel" such as Natural Gas) is an item of concern within my family and interest to me for some time now.

In the 1960's, coal was virtually supplanted by residual fuel oil here in the northeast. By the end of the 1970's we of course saw the folly in this and most of the local utilities made efforts to get away from fuel oil as their sole source of energy. Construction of Seabrook Station was PSNH's 1970's answer to reliance on foreign oil.

My own company (New England Electric System) prided itself on the "mix" of fuels that the wisdom of TPTB (including my father who was a proponant of mix and a "principle" in the company) decided upon. Coal, oil, nuclear, hydro, natural gas were all represented. Whichever way the marketplace turned, our company had enough generation of a fuel type available to cover their own load.

The beginning of the end of this period was in 1978 when a well intentioned Congress passed the PURPA laws which allowed *anyone* access to the powerlines to generate electricity for a price. Aimed at "small power generation" such as windmills, photo-voltaic installations, and small industry, the law has since been used as a club by national and international "consortiums" (such as Southern Company, PG&E Generation, Duke Power) to beat the formerly regulated utilities over the head and financially outdo them to the "electrical busbar." The built in "inefficiencies" of the regulated utilties didn't help them a bit.

Using newly developed combined cycle technology, the "newcomers" built their plants cheap, they built them quick, and they built them to burn natural gas.

The utilties realized they couldn't compete with these "newcomers" and decided instead to bail out. Hence the "deregulation" that has been occuring with the full assent and accord of the utilties. My own company enlisted on the Board of Directors the aid of a former Massachusetts Senate President whom we won't name to aid in the political hurdles to make deregulation happen in a manner favorable to the utility.

The downside of deregulation is that now it is easy to be "locked in" to whatever the "fuel of choice" is at the moment. Like Seabrook being seen as the answer to New England's overreliance on foreign residual oil, natural gas will become our next overreliance.

The upside of deregulation is that "free enterprise" will be the "chooser" of fuel supplies. A generous but volatile mix is likely the result. A lot of powerplants will be built by greedy investors which may never run due to competition.

Along side of all of this this, competing fuel supplies other than natural gas have come under fire because of cost (oil), hazards or heat pollution (nuclear), or environmental downsides (hydro and coal)

Natural gas survives at present because it has found itself a nice niche with presently a low price (lower than it's been previously anyway), environmental acceptability (half the "greenhouse gas" is produced since it has limited carbon) and the invention of devices such as gas turbines to utilize the fuel to it's fullest practical advantage (combined cycle operation.)

However, historically, natural gas has been a "premium" fuel. When I first started in the power industry, natural gas was burned only during the summer when heating loads were low and the gas companies had "excess." Now, with the increase in powerplant and industrial usage, no such surplus exists.

I predict that within our lifetime, natural gas will become "significantly expensive" and will be supplanted as a result. That is if economics and the forces of the free marketplace will let it be supplanted. As environmental rules are now headed with the EPA, natural gas may be the *only* fuel that will be allowed to be burned for electrical generation. The general "good feeling" our Executive Branch (thank you Mr. Gore) have regarding the Kyoto Accords and other "green global agreements" may eventually make grid electrical power the "lighting source of the rich."

I'll go a little further off the deep end here and propose that TPTB have this all in mind. We're going to become "green" whether we want to or not.

Perhaps this is a good thing. Americans are spoiled beyond belief concerning their energy supplies.

Having lost one job over an issue with "upper utility management" of improving power plant efficiency, I can vouch for the "self interested" view that most utilities have previously had regarding the consumer or the environment. This has not changed, I'm sure.

The truth of the matter is that capital cost and return to the investor are the raison-de-etre for any power company. Everything else is "market" or "constraints," which any successful utility executive survives by plotting a course down the middle. I think TPTB in guiding us to the path we are taking are looking to create both a new "market" and a new set of "constraints."

And you know what? TPTB will be there with their "highly efficient and environmentally compliant" combined cycle fuel cells (burning natural gas provided by a national or international consortium), their photo-voltaic panels (provided by the same companies), or their "highly efficient" automobiles (with hybrid technology available from only guess who.)

Yes, we're being manipulated.

Gosh I'm depressed.

Best regards,

-- Joe (KEITH@neesnet.com), February 23, 2000.

Joe,

I just got back to getting at your last response. It will take me some time to consider it in order to do it justice.

Once again, I sincerely appreciate the insights you have offered, as well as the time it had to take to formulate your information so well.

By the by, I am sorry about my questions leading you down a depressing line of thought, or of memories.

To me, the most interesting prognostication, long-term, lies in this paragraph of yours:

"I predict that within our lifetime, natural gas will become "significantly expensive" and will be supplanted as a result. That is if economics and the forces of the free marketplace will let it be supplanted. As environmental rules are now headed with the EPA, natural gas may be the *only* fuel that will be allowed to be burned for electrical generation. The general "good feeling" our Executive Branch (thank you Mr. Gore) have regarding the Kyoto Accords and other "green global agreements" may eventually make grid electrical power the "lighting source of the rich." "

I am struck here by the U.N.'s Agenda 21 plan to, essentially, turn everything West of the Ohio River back to full-blown wilderness, with only access corridors for human 'polluting'. That plan's creeping implementation certainly will cut our environmental emissions, not to mention the U.S.'s population. Now, who is going to tell the burgeoning, e.g., Spanish, illegals that they must stay in the corridors???

Real life is going to intrude here, for some hours. I plan on checking back on this thread sometime much later.

Thank you again! Your knowledge and your insights have been more interesting than you may have any idea!

-- redeye in ohio (not@work.com), February 23, 2000.

Good discussion.

-- Dee (T1Colt556@aol.com), February 25, 2000.