"Solar Energy is Now the Better Buy" after reaching a "Historic Crossover" according to a new study.

The costs for solar photovoltaic (PV) systems have fallen steadily while construction costs for new nuclear power plants have been rising over the past decade, which now makes electricity generated from new solar installations cheaper than electricity from proposed new nuclear power plants, according to a new report published by a retired Duke University professor.

Moreover, the report continues, solar costs are projected to continue its decline over the coming decade while nuclear costs are expected to rise further.

The report, “Solar and Nuclear Costs — The Historic Crossover: Solar Energy is Now the Better Buy,” was compiled by John O. Blackburn, Professor Emeritus of Economics and former Chancellor of Duke University, along with a student, Sam Cunningham.

Electricity generated from solar PV is now being sold by commercial developers to the utility companies at 14 cents or less per kilowatt-hour (kWh), while nuclear plants in the planning stages will be incapable of offering electricity cheaper than 14-to-18 cents per kWh, according to the report.

“The delivered price to customers would be somewhat higher for both sources,” the study notes.

Solar photovoltaic resource potential. (CLICK TO ENLARGE)

Cost estimates for new nuclear plants have risen dramatically since the much-heralded “nuclear renaissance” began during the past decade, says Blackburn. “Projects first announced with costs in the $2 billion range per reactor have seen several revisions as detailed planning proceeds and numerous design and engineering problems have emerged. The latest price estimates are in the $10 billion range per reactor.”

But Rod Adams, author of the Atomic Insights Blog, rejected the report and criticized the basis of the study, saying that the report’s nuclear cost projections rely on a paper written by a lone researcher with unclear qualifications. Mark Cooper’s “brief biography states that he has a ‘PhD from Yale’ but it does not specify his field of study. It indicates he is an ‘acivist/advocate’ with a rather wide range of interest areas including telecommunications regulations and energy consumer issues,” he writes. Adams also listed a number of papers on the subject which he says were ignored by Blackburn’s report.

“For many years the U.S. nuclear power industry has been allowed to argue that ‘there is no alternative’ to building new nuclear plants,” Blackburn’s report concludes. “This is just not true.”

By Lauren Frohne – UNC’s Powering A Nation

Powering a Nation’s reporters spent about two weeks in communities with nuclear power plants asking questions, getting opinions and weighing the facts to gain a better perspective on the nuclear issue. Hoping to see the inner-workings of a plant, they had an opportunity to tour Vermont Yankee Nuclear Power Plant in Vernon, Vermont. Larry Smith, the plant’s official tour guide, agreed to show them around.

Vermont Yankee Nuclear Power Plant as seen from across the Connecticut River. Photo by Lauren Frohne

The security

Not only were the reporters allowed to tour the plant, they were also permitted to bring cameras. But there were things that could not be photographed.

The radiation monitor that provides a live reading of exposure while touring the plant. Photo by Lauren Frohne

Namely, it was not possible to take pictures of any of the security measures implemented at the plant, including the perimeter fences, cameras and screening equipment.

 Since security is such an important part of a plant, the reporters first had to go through a screening similar to what you might experience at an airport. The security guard went through camera bags thoroughly. Then they received visitor badges, scanned their palms, and entered the plant through a tall, subway-like turnstile.

The first building inside the plant was a staging area where a plant worker (the only one the reporters saw until they exited the reactor building) was in charge of reading visitor responsibilities and setting up radiation monitors.

Reporters wore two monitors: one provided a live reading of their exposure while in the plant, the other recorded a more precise measurement to be mailed to them later. Also equipped with a hard hat, safety glasses and earplugs, the reporters began the tour.

The heat, the noise

As the journalists entered the reactor building, they were struck by the noise. A constant, brain-scrambling hum. At times, it got so loud they could only communicate with Larry through hand gestures. The turbine room was the loudest place in the entire plant. The heat was difficult to adjust to, as well. It was 100 degrees or hotter throughout the entire reactor building. Some places featured a “Do Not Linger” label in the hottest spots because the heat was a result of radioactive steam.

For the most part, the plant is a concrete building with all kinds of pipes and valves, slate-gray containers and warning signs. Few people occupied the premises. From what Larry told reporters, the plant bustles with workers more during their scheduled outage periods, which occur every 18 months and lasts about 30 days. During that time, the reactor shuts down and contractors come to the plant to perform maintenance and swap out fuel bundles. They recently completed their outage month, so the plant was mostly deserted during our visit.

Warning signs featured throughout the Vermont Yankee Plant. Photos by Lauren Frohne

The pool

The highlight of the tour was seeing the spent fuel pool. Spent fuel pools are where the majority of the spent fuel from a plant’s entire operational history is kept. Vermont Yankee houses about 38 years of spent fuel. 

Spent fuel is still extremely radioactive, but anti-proliferation laws prevent plants from reprocessing it and using more of their radioactive energy. The bundles are kept in pools that are about 40 feet deep (about the height of a four-story building) and enclosed in several feet of concrete. The water keeps the radiation contained and the fuel cool.

The pool is deep and serene. It moves gently. What at first seemed like a reflecting pool eventually revealed hundreds of canisters of spent fuel rods. Standing over so much radioactive material left journalists with a bizarre feeling: a little nerve-wracking, a little daring. Larry was the most nervous, though. He reiterated that people aren’t usually allowed to get that close to the pool for that long, let alone with a camera.

The “clean side”

The pool was the last stop on the tour of the interior of the plant. The reporters weaved their way back through the tunnels and stairways and reinforced doors back to the staging area, which also serves as the the radiation screening area.

On their way out, their possessions had to go through a radiation detector, and then placed on the “clean side.” The “clean side” was literally on the other side of the small turnstile through which we had entered the reactor building.

Then it was the reporters’ turn. They had to stand in two different machines that scanned their entire bodies for radiation. These machines require you to stand still while a female, British voice counts down from 10 or 15. Despite some small exposure, the journalists were deemed acceptably clean.

Before the crew explored the exterior of the plant, one of the reporters would make a little mistake that would later have them hustled out of the plant.

The dry storage

The first stop outside was the above-ground, dry cask storage. These five giant, concrete and steel casks were assembled because the spent fuel pool is reaching capacity and Vermont Yankee anticipated being able to send some of their radioactive waste to Yucca Mountain. That plan has now been canceled. Many plants in the U.S. will need to resort to dry cask storage soon as many are reaching capacity in their spent fuel pools as well. The storage and transport of radioactive nuclear waste is a major, hot-button issue in the nuclear debate. The thought of having nuclear waste, which will continue to be radioactive for over 100,000 years, sitting out in a cask (that has a registered use of only 100 years) with nowhere to go, is somewhat unsettling.

The dry cask storage units outside of the Vermont Yankee plant. Photo by Lauren Frohne

Next, the crew visited the low-level radioactive waste that is kept in large, steel shipping containers. This includes things like papers, office supplies, radiation suits and other things that might have been exposed to radiation at some point. This is also radioactive matter that is sitting out, waiting to ship, with nowhere to go. Like many plants in the U.S., Vermont Yankee used to send this low-level waste to a waste storage facility in Barnwell, South Carolina. However, this facility recently stopped accepting waste from the 14 states from which it used to accept waste. Plant Vogtle also has this same issue to deal with.

The last stop was the location where the plant takes in water from the Connecticut River. Most nuclear power plants are positioned on a major river because of the huge amount of water required to cool the process. Larry said that this reactor uses 365,000 gallons of water a minute.

Setting up a last shot of the river’s rushing water, the reporters were approached by a security guard with a machine gun slung around his back. The armed guard escorted them out as Larry speculated nervously about the quick exit. He told them how they had been watched from the very moment they entered the plant.

Fortunately, it was an innocent mistake. When they were turning in radiation monitors, one of them discarded her visitor badge. Without a badge, she was breaching the plant’s security protocol, which requires all visitors to carry proper identification. The crew hustled back to the welcome center.

On the way, they convinced Larry to let them linger around the cooling towers to shoot video, while he talked nervously with his supervisor on the phone. Their towers are induced-draft cooling towers, not the traditional hyperboloid towers so often associated with nuclear power. The plant, which is across the street from an elementary school and a residential neighborhood, chose to use less visible towers.

Exhausted, sweaty and with 0.7 milliren of radiation exposure, their tour of Vermont Yankee Nuclear Plant came to a close. From a journalistic standpoint, it was an amazing experience and something that not many people get to see or photograph.

The induced-draft cooling towers at Vermont Yankee. Photo by Lauren Frohne

Written by Lauren Frohne under the auspicies of UNC’s Powering A Nation and shared with Consumer Energy Report.

The following article is provided by UNC’s Powering A Nation journalism team.

Our focus on emerging energy issues has carried us to Burke County, Ga., a sparsely populated community of more than 22,000, located 25 miles south of Augusta. Burke County now finds itself at the center of the Obama administration’s emphasis on nuclear power as a viable answer to America’s energy predicament.

Georgia Power, a subsidiary of Southern Company, provides 15 percent of Georgia's power through Plant Vogtle. Plant Vogtle will be the first nuclear license to be issued in 30 years if granted a license by the Nuclear Regulatory Commission, and it will be the only site in the U.S. with four reactors. Photo by Lauren Frohne

President Obama announced in February that Southern Company would receive $8.3 billion in loan guarantees to build the nation’s first nuclear reactors in 30 years. Plant Vogtle already houses two nuclear reactors. Unit 1 went online in 1987, and Unit 2 went online in 1989.

The current project serves as a $14 billion capital investment in Georgia and promises to bring more than 3,500 construction jobs and more than 800 permanent jobs.

The twin cooling towers stand 548 feet high, roughly equal to a 55-story building and taller than the Statue of Liberty (456 feet). Photo by Jessey Dearing

Construction on Plant Vogtle’s site began in April 2009 and is projected to last until 2017. If the Nuclear Regulatory Commission grants a Combined Construction and Operating License in late 2011 or early 2012 as expected, the project will bring Unit 3 online in 2016 and Unit 4 online in 2017.

Mike McCracken, spokesman for Southern Nuclear Public Affairs, said Plant Vogtle would be the only nuclear power plant in the U.S. with four reactors.

We did find some individuals in the Burke County community who seem skeptical of bringing more nuclear reactors close to their community. They expressed concern at how much of the land where they used to roam without worry—Plant Vogtle has a 3,100 acre site along the Savannah River–is now surrounded by “No Trespassing” signs. They lamented the fact that they could no longer fish in the Savannah River for fear of pollution. And they used the recent oil spill in the Gulf to discuss the uncertainty of what happens if there is an accident at Plant Vogtle.

Despite those concerns, George DeLoach, the mayor of Waynesboro, Burke County’s seat, said that in an economic downturn, the construction of the two nuclear reactors means money for the county. Already, the plant provides 70 percent, or $25 million, of the county’s tax base. DeLoach said Units 3 and 4 could mean a doubling of that amount to between $50 and $60 million.

And, DeLoach says, the jobs that are coming to Burke County help quell consternation a resident may currently hold. “Because of the economic situation that we’re in now, jobs mean more to them than the environment,” he said. “Everybody wants a good job.”

How dangerous are the towers?

Plant Vogtle's twin cooling towers stand on Southern Company's 3,000 acres of land in Burke County, Georgia. In the foreground, land has been cleared for the construction of Vogtle's two new reactors and cooling towers. Photo by Lauren Frohne

Cooling towers are an iconic symbol of nuclear energy. Visible from a dozen or more miles away, they are, for some, the representation of an unwanted neighbor; for others, they’re beacons of a clean energy future.

Despite the cooling tower’s intrusive appearance, it is probably the most benign part of a nuclear power plant, based on what we recently learned during a tour of Plant Vogtle in Burke County, Georgia. The towers can appear daunting, but when it comes down to that part of the nuclear energy process, it’s nothing but water.

Facts about cooling towers:

• Nuclear reactions do not occur in the cooling towers.
  • The actual reactor is typically enclosed in a cement building that is built to withstand natural disasters and other threats.
• They are not just used for nuclear power plants.
  • Many coal plants and other industrial facilities that boil water and use steam to turn a turbine use them to cool water before releasing it into the lake or river from which it came.
  • There are nuclear power plants that do not use cooling towers, but instead utilize other methods for cooling water vapor into liquid.
• The substance that billows out of the top of a cooling tower is just water in the form of vapor.
  • The water that is released never comes in contact with any radioactive material. At Plant Vogtle, that water is brought into the plant from the Savannah River through pipes. It is used to cool down the steam that turns the turbine so it can condense and be used in the process again. Because of the high temperatures, some of the river water is released as steam, while the rest flows back into the river.
• One cooling tower at Plant Vogtle consumes about 15,000 gallons of water per minute.
  • Between the two, that’s 43.2 million gallons per day.
  • With the addition of two more towers to accommodate the two new reactors they have planned, the plant will use 86.4 million gallons of water a day.
  • According to Plant Vogtle’s website, their current reactors use “1 percent of the average annual flow of the Savannah River. Adding two additional units at the site would increase that amount to 2 percent.”

Two cement domes enclose the nuclear reactors at Plant Vogtle. Radioactive materials and waste are housed in the domes and conjoined buildings. At its narrowest part, the cement dome is three feet thick. Some parts of the dome are as thick as nine feet. Photo by Lauren Frohne

Though the cooling tower is relatively gentle in nature, it is capable of interrupting even the most picturesque landscape. For Jessey, Chris and me, this was our first time beholding one at such close proximity. The photographers in the group that visited Burke County had fun juxtaposing the towers with the beautiful scenery we found there.

Predominantly rural, Burke County is one of the largest counties in Georgia in terms of square miles, but it has a population of only about 24,000. Photo by Lauren Frohne

Written by Chris Saunders and Lauren Frohne under the auspicies of UNC’s Powering A Nation and shared with Consumer Energy Report.

Living up to its name and motto, GreenLaw launched a legal attack against two proposed coal based power plants yesterday.

A coalition of environmental groups filed five challenges in Georgia State Supreme Court, on Monday, hoping to delay or derail the development of two coal power plants in Early County.

The disputed developments are Longleaf Energy Plant, a project developed by LS Power for Early County, and Plant Washington, a medium-sized plant that would be built by an energy consortium in Sandersville, Georgia.

“Innovative, clean ways of producing energy are economically feasible and Georgia has energy efficiency measures to meet the economic growth that we expect,” according to Erin Glynn of the Sierra Club in Georgia.  “Coal is a dirty, dangerous business. From the mine to the smokestack, coal-fired power is outdated, risky, and unnecessary.”

The motions were filed by GreenLaw and the Southern Environmental Law Center acting on behalf of Fall-line Alliance for a Clean Environment, Ogeechee Riverkeeper, Sierra Club’s Georgia Chapter, and the Southern Alliance for Clean Energy.

The petitions allege that state regulators failed to classify the proposed 1200 megawatt Longleaf Plant as a “major” source of air pollution, thereby enabling the coal power producer to operate under laxer standards than are appropriate for a plant of its proposed size.  Additionally, they claim that Plant Washington, which would produce 850 MW of power, will discharge harmful air pollutants while posing a threat to water supplies for neighborhoods along the Oconee River sited downstream from the plant.

“Hazardous air pollutants from the plant will compromise the Ogeechee River basin,” Ogeechee Riverkeeper representative Chandra Brown said. “Our recent report, Protect Yourself and Your Family from Mercury Pollution, shows that additional mercury deposition from Plant Washington would prevent people who fish from safely eating the fish they catch.”

The developers counter that the coal plants are necessary to support a rapidly developing population in the region.  They claim that Plant Washington alone, the smaller of the two plants would power over half a million homes within the next 5 to 6 years.

Additionally, the consortium supporting the project claim that the plants would help revitalize the region’s struggling job market by providing over 100 full time jobs once operations commence.

Dean Alford, president and CEO of Allied Energy Services, a development firm that’s part of the consortium believes that the environmentalists’ motions consist of empty rhetoric.

“They’re throwing a bunch of stuff on the wall and hoping that something sticks,” said Alford.

“We think it’s important to find a way to provide environmentally sensitive, reliable and affordable energy in the state,” Alford added. “Georgia’s going to have to build new energy solutions and we think clean coal is one of the best solutions.”

MPC seems likely to pull out of its proposed plans to create a new coal plant in Kemper County.

Mississippi Power Co. (MPC) may abandon construction of a coal plant in Kemper County after receiving a decision from the Mississippi Public Service Commission (PSC) capping spending on the venture at $2.4 billion.

The decision contained several conditions that MPC would need to abide by if they were to construct the proposed 582-megawatt integrated gasification combined-cycle (IGCC) plant.

While MPC initially stated that they could construct the plant for $2.4 billion, their recent findings indicate the project would cost $3.2 billion.

“We are disappointed in this decision,” said company spokeswoman Cindy Duvall.

The PSC conditions “seem to make it impossible for Mississippi Power to finance or construct the Kemper County IGCC Project even if the right to construct had been — or might in the future — be allowed,” Duvall added.  “We put forth the best option available to us to meet our customers’ needs with reliable and affordable energy.”

MPC planned on using the IGCC to burn lignite coal to meet future electricity demand and give the utility 21^st century reduced emissions options for its aging coal plants.

A decision to forego the project could cost the county jobs.  The plant would have created 1,000 jobs during the construction phase and 260 permanent jobs.

“We’re going to keep praying it happens,” said James Granger, president of the Kemper County Board of Supervisors.

The vote came via a 2-1 decision. PSC Chairman Brandon Presley voted against it, warning that the cap would not “sufficiently protect the ratepayers of Mississippi Power Co from the great risks associated with the construction of this project.”

Bearing little resemblance to prototypical lasers, NIF's laser (pictured above) is not merely the largest in the world, it may one day be capable of harnessing energy similar to a star.

Searching for an answer to the global energy crisis, government scientists are attempting to create a high energy reaction using nuclear fusion which would have similar potential energy to a small star.

The Lawrence Livermore National laboratory has created a laser the size of three football fields — easily the largest laser in the world – for the purpose of creating the reaction.

“We have a very high confidence that we will be able to ignite the target within the next two years,” thus proving that controlled fusion is possible, said Bruno Van Wonterghem, a manager of the project, which is called the National Ignition Facility (NIF).

Cynics point to the fact that nuclear fusion was introduced five decades ago as a potentially credible energy source and has thoroughly failed to live up to its hype.

Worse yet, this month the U.S. Government Accountability Office  released the results of an audit at NIF which lists technical difficulties to be overcome, inexplicable delays in implementing prior recommendations and poor managerial decisions as reasons the project has stalled.  That being said, the US GAO still seems to support the project if NIF can improve their implementation of recommendations on this go-round.

The recipe for creating the proposed nuclear fusion reaction, described in layman’s terms, sounds very much like an explanation typically given in a Grade B science fiction novel.

1. Build an enormous laser.
2. Split the laser into 192 separate beams.
3. Concentrate all 192 beams on a single point.
4. Apply reactive isotopes of hydrogen in a gold capsule to the focal point of the beams.

NIF anticipates that the nuclear reaction they plan on creating will produce more intense heat than is located at the center of the sun.

The project designers hope that the resulting reaction will produce more than 100 million degrees Celsius – hotter than the center of the sun – and exert more pressure than 100 billion atmospheres. Ideally the hydrogen isotopes will smash together with sufficient force and heat that their nuclei will fuse, sending off energy and neutrons.

Project spokeswoman Lynda Seaver claims that the endeavor does not pose any risk to public health.  “There’s no danger to the public,” said Seaver.  “The [worst possible] mishap is, it doesn’t work.”

This summer, NIF hopes to try its first test run, creating a star that will be 5 microns (smaller than the width of a human hair) and die 200 trillionths of a second after it’s ignited.

“This is something you’re going to tell your grandchildren about,” Seaver told CNN. “You were here when they were about to get fusion ignition.

“It’s like standing on the hill watching the Wright brothers’ plane go by.”

A new report claims that coal based power plants create more emissions than they normally would because utilities must comply with pro-wind energy policies.

The natural gas industry has produced a new report which claims that increased use of wind energy cause coal-fired power plants to “cycle” unconventionally and thereby cause an increase in the pollution levels they traditionally produce along Colorado’s Front Range.

Bentek Energy LLC, a consulting company, for the Independent Petroleum Association of Mountain States, conducted the report titled “How Less Became More: Wind, Power and Unintended Consequences in the Colorado Energy Market”.

“It’s not the wind that’s doing it; it’s what the wind energy is causing in behavior changes at the plants,” Bentek’s president Porter Bennett said.

According to the report, local ordinances in Colorado require utility companies to avail themselves of wind energy when it is available.  Compliant utilities are required to cycle coal plants on and off, most frequently at night when there tends to be more wind.  Because the coal plants are shutting down and restarting at irregular and unpredictable intervals they operate inefficiently and sustain interference with emission control equipment resulting in increased sulfer dioxide, (SO2) nitrous oxide (NO2) and carbon dioxide (CO2) emissions.

Data for the report came from evaluation of four years of emissions records from individual power plants owned by Xcel Energy Inc in Colorado. Emissions levels are reported to the federal government on an hour-by-hour basis.

Barring modifications to Colorado statutes, the report indicates that the problem may get worse in the future.  Presently, utilities companies operating in Colorado are required to furnish 20% of their energy through renewable sources.  Last Month, Gov. Bill Ritter signed a law bumping that requirement to 30% by 2020.

Natural gas power plants"cycle" on and off more efficiently than their coal counterparts.

The report recommends curbing the use of wind energy during the next one or two years to levels that match power output at existing natural gas-fired power plants — and building more natural gas plants in the long term.

According to the report, natural gas plants can ramp up and down without increasing emissions like their coal based counterparts.

The report could have a nationwide impact.  Congress is considering introducing a bill which may set standards for renewable energy sources nationally.  Accordingly, the ramifications of the report may extend far beyond Colorado’s four corners if it sways Congress to consider its findings during bill deliberations.

Furthermore, authors of the report claim that increased emissions from coal based power plants are not unique to Colorado as they found similar results in Texas.

Wind energy advocates, however, claim the report is flawed.

“The aggregate numbers are what they are,” said Michael Goggin, American Wind Energe Associan’s (AWEA) manager of transmission issues. “When you’re adding wind power, a zero-emissions resource to the grid, that power has to displace some of that other power. You’re driving off coal or natural gas. Wind is displacing fossil fuel generation and it’s a zero-emission resource.”

Bennett counters that the AWEA’s numbers are misleading.

“One of the points of our study is that you can’t look at aggregated data; you have to go down and look deeper because the aggregation masks the real reality,” Bennett said.

Emissions levels statewide declined during the subject four year period, in part, due to new emissions control equipment that Xcel added to its Comanche coal-fired power plant in Pueblo, Bennett said.

The following guest post is by Dave Summers. Dave is known on The Oil Drum as Heading Out, and he is friend of mine and a recently retired professor from the Rock Mechanics and Explosives Research Center at Missouri University of Science and Technology. Dave maintains a very informative blog called Bit Tooth Energy that seeks to educate people on technical issues around the extractive industries.

I have intended to write something about the mining disaster, as it is a stark reminder of the dangers involved in the mining industry. Some of you may remember that I recently reviewed Big Coal, and in that book author Jeff Goodell was highly critical of Massey CEO Don Blankenship’s track record on safety. In fact, Goodell pulled no punches in a New York Times article following this disaster. While acknowledging that underground mining has inherent risks and that the safety record has improved, Goodell argues that Blankenship has used political influence to water down safety reforms:

“The second reason mine safety reforms have failed is the political power of the coal industry. After every coal mining tragedy, there are passionate calls for new safety rules and regulations. After those reforms are proposed, they are fought over in Congress and state Legislatures, where politically connected coal operators make the case that the reforms are too onerous, too expensive, too difficult to implement. And so they are watered down, loopholes are inserted, timelines extended.

This is particularly true in West Virginia, where Don Blankenship, the head of Massey Energy, the coal company that owns the Upper Big Branch mine, holds sway over state politics there like one of the old coal barons of yore. In West Virginia, you mess with Don at your peril. If you want to know why a mine with a sorry safety record like Upper Big Branch wasn’t shut down long ago, that’s your answer.”

My thoughts are with the friends and families of the miners who perished.

With that introduction, here is Dave’s excellent and very comprehensive essay weighing in on the matter.

—————————————–

The news of the death of at least 25 coal miners at the Upper Big Branch Mine in West Virginia is a reminder of the human costs that are incurred in the provision of fossil fuels. Although American mines have grown considerably safer over the years, the nature of the work can mean that when there is an explosion in a mine, that there are multiple fatalities because of the layout which is most effective for getting the coal out. It also underlines the higher costs that must be met when mining coal from underground operations, rather than the more visible, and criticized surface mining operations.

In the United States this is the largest mining disaster in more than 25 years at a mine that produced 1.2 million tons of metallurgical coal last year. Because of the pressures on surface mining operations Massey Energy were moving an increasing percentage of their production to the underground. The mine uses longwall techniques as the main means for producing coal and so I thought that it might be helpful if I reposted some of the information on that technique.

Part of the problem in controlling the ignition of gas in such an operation is that the mining machine breaks out the coal in relatively small fragments, by rotating a drum laced with picks against the coal face.

Surface test of a shearer used in longwall (Bureau of Mines Bruceton)

The fine crushing of the coal can lead to the release of methane gas (natural gas) that is found and formed with the coal. Levels of the gas are measured, and controlled by sending enough air down the face to dilute the level of the gas below that at which it is at risk of ignition or explosion. However within the space that the drum is carving out it is not always possible to get that air flow into the area to ensure that dilution is immediate.

At the same time if there are layers of rock within the coal, then the pick can rub against these and generate sparks, and heat up the rock to the point that it becomes hot enough to ignite any methane pockets that have been released. Once that ignition starts the very fine coal dust that is also a part of mining (as the above picture shows) means that this can also ignite, intensifying the resulting explosion. That becomes particularly deadly, given the geometry of the longwall.

And to explain that let me repost something I had written about before.

Back in the mid-1800’s underground mining was usually carried out by crews of men and boys, where the coal was first removed by undercutting the coal seam manually with a pick, to a depth of about 3 ft. The bulk of the coal was then broken down to this slot and the fragments (ideally about 4-inches in size) were shoveled and hand-loaded into pit tubs, to be hauled away. A good day’s work was about 20 tubs.

As the miners drove the tunnels (also called entries, headings, drifts, drives etc) into the coal they left pillars between the tunnels to hold the roof up. However in about 1870, and possibly in the Lancashire coalfield in the UK, they discovered that if they put these entries together, they could develop a way of getting all the coal out from that section (or panel). How could they get away with this?

Well there are two things that make it possible. Firstly, when you make a hole in the ground, the rock pressure that was applied to the rock (about the same pressure as the depth of the hole) has to move somewhere. And it moves just a little so that the weight of the ground over the hole is carried by the rock on either side. However, what happens if this additional load is too high for the rock and it fails?

Well if the rock were just a thin column it would collapse, but if it were thicker, then the weight would just move further into the coal. Now if we came along and moved the coal that had failed, then the hole would just continue to get bigger. But if we leave the coal in place, then the broken coal acts to confine the coal further into the solid. And this confinement gets higher, as the failing pressure continues to move into the wall. And what happens is that this confinement builds up the strength of the coal, so that at some distance into the wall (or face) the coal strength reaches a point that it can carry the weight of the ground above the working area.(For a simple analogy think of a deck of cards, which individually cannot bear weight, but when held together by a rubber band, or a carton, can support quite a bit of weight).

The second thing to know is that when a layer of rock breaks the rock lumps when piled together occupy more space than the solid rock. As a rule-of-thumb the bulking is about 60%. So that if we let the roof over the working area break and collapse, after we have taken the coal out, then by the time about twice the seam height of rock has collapsed, it has filled the hole where the coal used to be, and reaches up to the solid layers of rock above, to hold them in place. The confinement of the rock around each piece allows it to regain some strength, and so collectively the broken rock behind the working face (called the goaf or waste) will carry the weight of the ground from about twice the seam height, all the way to the surface, and with the other end of the “bridge” as it were resting on the confined coal ahead of the working face.(While the width of this bridge varies with depth, coal and rock strength etc, for an initial estimate you can imagine it as being around 500 ft).

What this means is that the miner, working at the face, needs to support only the rock that is up about twice the seam height above his head (in those days women did not do the actual mining). And this could be done with relatively small tree limbs, called props. However, because the rock could break into pieces, the prop support would be distributed, by having a plank, or half split timber, as a bar on top of the prop. Putting one prop at each end thus gave a sort of “goal post” support. Thus, along the face, there would be, at about 4-5 ft intervals, these prop supports holding the roof up.(The coal is made slightly blue in the pictures to give a better contrast – sorry!)

Now, to get the coal out it was possible to put in mechanical assistance. The first step was to use a machine, rather like a large chain saw, that was pulled along the face, undercutting the coal, to give that first free surface. At the same time holes were drilled along the face, about 6 ft apart, with a stick of dynamite in each one. After the face was cut the coal was blasted down between shifts (7.5 hours) then the collier shift would come in and each man would have about 10 yards of face to load the coal from, and to re-support. To get the coal from the face, a rubber conveyor belt was run along the back end of the supports that were in place before the blast, and the coal would normally not break that far from the face. As the miner shoveled he would also put in a new set of timbers, overlapping the old, and supporting the new working area. Typically this would take another seven hours, with an ideal seam height being about 4.5 ft. Above that the coal volume to move was much greater, and below that it got a bit awkward. For example, below 2 ft thick you lie on your back, with a prop under your shoulder and shovel over your head – how would I know? Yes, there was a reason to go to college).

In the third shift, the men would come in and break down and move over the conveyor belt, and then remove the last row of wooden supports, bringing the roof down, beyond the new line of supports.(Smart folk would use a come-along and a chain to pull down the props, young idiots (guess who) would go in with an axe to chop them first).
The process needed mechanization and this required three different components to work. And these all came together in a period around 1960 – 65. Firstly there was a better way of removing the coal. The machine that was developed initially took the coal cutter power pack, and turned it on its side. By then putting a drum with picks on it, over the shaft to replace the cutter bar, the Anderton shearer was invented (named after its inventor). The drum rotated, and a shaped cover behind it moved the broken coal over onto the second part of the process.

This is a rigid framed conveyor, made up of segments that can move against one-another, and with rigid metal walls. The shearer can ride either on top of, or along side this conveyor, and load the coal onto it. The conveyor then carries the coal to the end of the face, and onto a second conveyor, that carries the coal out of the panel.

It is the third part of the concept that makes the whole system viable, because we now add the powered roof support. These are sets of hydraulic rams that ride on one plate of steel, pressing a second up against the roof. They are connected to the conveyor by a horizontal ram.

The mining process is thus that first the shearer moves down the coal face, grinding off the coal to a depth of around 2 ft. After it passes, the rams on the roof supports, in turn, are released, so that they drop away from roof contact. The horizontal ram is retracted and the support moves forward until it contacts the conveyor. It is then raised, and re-supports the roof. Each support moves forward it turn, so that the miners (which now include women) are always under a roof of steel. After the supports are re-established, the horizontal ram extends, pushing the conveyor over into the open space where the coal has just been mined. The exposed roof rock then collapses into the open space behind the back of the supports.

If one were to look at the operation from above, and with the roof removed, it might look a little like this:

I have taken away some of the canopies of the shields so that you can see the conveyor snake after the shields move forward. The view closer in shows the conveyor and supports better.

Because of the way the roof rock weight distributes, it is usual to drive entries out to the edge of the panel first, and then mine back to the main drive tunnels, rather than mining away from the mains. In part this is to keep the excess weight from acting on the tunnels the miners travel through. Because of the collapse of the roof as the coal is removed the panels usually start at the back of the section (known as a panel) and mine toward the main transport tunnel, with coal and people travelling in roadways on either side of the panel.

Initial stages of a longwall panel development, showing how the access tunnels from the main haulage are located.

Over time the ground movement works to the surface, and the surface of the ground will drop, by some significant percent of the height of the coal removed, since the rock in the waste will crush and consolidate. This is called subsidence, and if the mining is carried out badly, then it can cause significant damage to surface buildings. However, if done properly, it should not.

I will cite two examples of the latter. Firstly in the height of mining and before North Sea Oil and Gas, Britain mined coal at a high rate of production, from where it was found. This included under the city of Coventry, which was at the time home to large manufacturing plants, with precision lathes. By back-filling behind the face props with the blown-in waste from the colliery treatment plant (called stowing the goaf), the waste was filled, and the ground movement minimized to the point that I only heard of one factory being closed for less than a week to realign their lathes.

The second example was in Duisburg in Germany, and a different problem. The town is a port on the Rhine, and over the centuries the river had eaten into the bed, so that the quays were becoming too high above the water for easy loading of the barges, and the town was losing business. They went to the local coal company and asked them to mine out seams under the harbor, and thus to lower the quays to bring them back in reach of the water. The miners complied, and lowered the area by over 11 ft. The area that was mined included highway overpasses, and a Shell oil storage facility in the middle of the river. The story goes that the tank farm manager went to the miners and asked them to tell him when they were going to start, so that he could drain the tanks as a precaution. They pointed out that the farm had actually already been lowered about 3 ft, as I recall the story.

As usual this has been rather a superficial description of a process, but hopefully it gives you more of a sense as to what goes on in a longwall mining operation.

Additional comment : It is possible to mine coal without using picks in a longwall, though it is a technology that has found much greater application in other industries, beyond mining.

Our thoughts and prayers go out to those in West Virginia at this time.

(RR comment: Dave has also written a follow-up post to this: More explanations of coal mine gas and coal dust explosions)

DOE’s CCPI Helps Commercialize Process That Also Reduces Costs and Potentially Harmful Emissions

Washington, D.C. — An innovative coal-drying technology that will extract more energy from high moisture coal at less cost and simultaneously reduce potentially harmful emissions is ready for commercial use after successful testing at a Minnesota electric utility. The DryFining™ technology was developed with funding from the first round of the U.S. Department of Energy’s Clean Coal Power Initiative (CCPI).

The United States has about 280 power stations burning high-moisture coal, generating more than 100 gigawatts of electricity, which equates to about one-third of the electric power generated by coal in the country.

Great River Energy of Maple Grove, Minn., has selected the WorleyParsons Group to exclusively distribute licenses for the technology, which essentially uses waste heat from a power plant to reduce moisture content in lignite coal. Great American Energy, a 50-50 joint venture of Great River Energy and the North American Coal Corporation, will also market the technology, whose first user will be the utility’s Spiritwood Station under construction near Jamestown, N.D.

In addition to using power plant waste heat to reduce moisture, DryFining also segregates particles by density. This means a significant amount of higher density compounds containing sulfur and mercury can be sorted out and returned to the mine rather than oxidized in the boiler. The end result is more energy can be extracted from the coal while simultaneously reducing emissions of mercury, sulfur dioxide, and nitrogen oxides, major potential pollutants that result from coal-based combustion.

As part its CCPI-funded project, Great River Energy tested a 115-ton prototype dryer in the company’s 546-megawatt Coal Creek Station Unit 2 in Underwood N.D. Following a successful increase in boiler efficiency and reduction of emissions, Great River Energy expanded the project by building full-scale dryer modules for the entire Coal Creek Station. The Office of Fossil Energy’s National Energy Technology Laboratory manages the CCPI program.

Lignite is one of four major coal types produced in the United States, accounting for about 7 percent of annual production, and is an important energy source for electricity generation. In general, lignite has a higher moisture and ash content, resulting in a lower power efficiency and higher rate of emissions than coals with less moisture. Great River Energy’s innovative technology reduces the cost of drying coal by using the waste heat and segregating particles by density, thereby generating energy with less coal while reducing emissions and emission-control costs.

At the Coal Creek Station, the technology increased the energy content of the lignite from 6,200 to 7,100 Btus per pound, thereby reducing fuel input into the boilers by 14 percent. At the same time, sulfur dioxide and mercury emissions were reduced by more than 40 percent, nitrogen oxide by more than 20 percent, and carbon dioxide by 4 percent.

These results are important to energy consumers because the United States has about 280 power stations burning high-moisture coal, generating more than 100 gigawatts of electricity, which equates to about one-third of the electric power generated by coal in the country.

Release: National Energy Technology Laboratory

A single B&W mPower™ nuclear reactor module inside its own independent, underground containment.

In his State of the Union address, President Obama referred to a “new generation” of nuclear power plants. The President was either exceedingly prescient or he knew more than he revealed because one week later the new generation has arrived–introducing the Babcock & Wilcox reactor. The energy world is taking notice.

Three large utilities, Tennessee Valley Authority, First Energy Corp. and Oglethorpe Power Corp., signed an agreement with McDermott International Inc.’s Babcock & Wilcox subsidiary on Wednesday, committing to get the new reactor approved for commercial use in the U.S.

While the three companies have not yet committed to purchase any of the reactors, their commitment to obtaining regulatory approval for the enterprise is a critical initial step toward implementation.

Approximately one-tenth the cost of conventional nuclear power plants, the newer designs are smaller than a rail car, offer greater flexibility of site location and theoretically can be built in half the time. These advantages, most notably the price, make the Babcock & Wilcox reactor a more attractive nuclear option for energy companies than conventional reactors.

Traditional nuclear reactors may produce more energy than the new “mini-reactors” but they cost many billions of dollars. The Babcock-Wilcox reactor runs closer to $750M. “We think the probability that things will go wrong with these large projects is greater than the probability that things will go right,” said Jim Hempstead, senior vice president at Moody’s Investors Service.

Comparatively, the cheaper reactors offer less risk of financial ruin. The reduced risk translates into a self-fulfilling prophecy for an investing corporation’s financial future. Larger, riskier ventures are more apt to damage a corporation’s credit rating than a more “bite-sized” investment in smaller reactors.

Not every corporation moving toward nuclear power needs to rely solely on strong credit ratings for financing, however. President Barack Obama recently pledged to guarantee 8.3 billion dollars in loans for the construction of large nuclear power plants in Burke, Georgia.

The White House pledge was somewhat groundbreaking for a country that has not built a new nuclear power plant since the Chernobyl meltdown in the Soviet Union several decades ago. It was a particularly surprising development because President Obama is viewed by many as a leader whose primary focus is the environment.

Environmentalists are not happy with the President’s new trend. Between the President’s shifting toward off-shore drilling and nuclear power he seems to be turning on his own political base. The White House’s recent trending toward the right has not passed unnoticed by the left.

Friends of Earth President Erich Pica is not smiling about recent White House decisions.

“Green” enthusiasists like Friends of the Earth president, Erich Pica, feel that Mr. Obama’s recent policy emphasis amounted to “unilateral disarmament.”

“We were hopeful last year; he was saying all the right things,” Mr. Pica said. “But now he has become a full-blown nuclear power proponent, a startling change over the last few months.”

If eco-diehards are disgruntled now, that frustration is likely to build. Some experts believe that introducing small reactors to the industry could pave the way for more pervasive, nuclear power in the U.S. because more utilities would be able to afford them.

“There’s a higher likelihood that there are more sites that could support designs for small reactors than large ones,” said David Matthews, head of new reactor licensing at the Nuclear Regulatory Commission.

The President has gone on record as saying, “the fact is, changing the ways we produce and use energy requires us to think anew, it requires us to act anew, and it demands of us a willingness to extend our hand across some of the old divides.”

That ideology is consistent with the new wave toward mini-reactors.

“If we can’t figure out how to build large plants economically, then small ones may be the way to go,” said Ronaldo Szilard, director of nuclear science and engineering at the Idaho National Lab, part of the Department of Energy.