FT142: “Solar and wind power would take the longest to restore after a devastating weather event.” —Old Pithy

Posted by PITHOCRATES - November 2nd, 2012

Fundamental Truth

Neither Snow nor Rain nor Heat nor Gloom of Night Stays the Production of Electric Power from Coal

What’s the best way to generate electric power?  This is not a trick question.  There is an answer.  And there is only one correct answer.  Coal.  A coal-fired power plant is the best way to generate electric power.  Coal-fired power plants can run 24 hours a day, 7 days a week, 365 days a year.  You never have to turn them off.  They can produce an enormous amount of power for the given infrastructure.  You can put these power plants anywhere.  Where it’s snowy and cold.  Where it’s bright and sunny.  Where it’s cloudy and rainy.  It doesn’t matter.  Coal-fired power plants are like the US Postal Service.  Neither snow nor rain nor heat nor gloom of night stays the production of electric power from coal.

Coal is a highly concentrated form of energy.  Burning a little of it goes a long way.  This is why one coal-fired power plant can add over 2,000 megawatts to the electric grid.  And why about 600 coal-fired power plants can provide over half of our electric power needs.  Coal is one of the most abundant fuel sources in the world, too.  In fact, America has more coal than we can use.  This high domestic supply makes coal cheap.  Which is why coal-produced electric power is some of the cheapest electricity we have.

The only thing that will shut down a coal-fired power plant is running out of coal.  Which doesn’t happen easily.  Look around a power plant and you will see mountains of coal.  And conveyor systems that move that coal to the firebox that burns it.  You’ll probably see more coal arriving.  By unit train.  Trains with nothing but coal cars stretching a mile long.  By river barge.  Or Great Lakes freighter.  Making round-trip after round-trip from the coal mines to the power plants.  We’ve even built power plants near coal mines.  And fed those plants with coal on conveyor systems from the mines to the power plants.  Trains, barges and freighters use self-contained fuel to transport that coal.  And electric power energizes those conveyor systems.  Electric power that comes from the power plant.  Making it difficult to interrupt that flow of coal to our power plants.  Onsite stockpiles of coal can power the plant during brief interruptions in this coal flow.  When the lakes freeze they can get their coal via train.  And if there is a train wreck or a track washout they can reroute trains onto other tracks.  Finally, coal-fired power plants are least dependent on other systems.  Whereas a natural gas-fired power plant is dependent on the natural gas infrastructure (pipelines, pumps, valves, pressure regulators, etc.).  If that system fails so do the natural gas-fired power plants.

Solar Panels produce low DC Currents and Voltages that we have to Convert to AC to Connect them to the Electric Grid

Neither snow nor rain nor heat nor gloom of night stays the production of electric power from coal.  But they sure can interrupt solar power.  Which won’t produce much power if there is snow or rain or night.  Giving it one of the lowest capacity factors.  Meaning that you get a small fraction of useful power from the installed capacity.  Wind power is a little better.  But sometimes the wind doesn’t blow.  And sometimes it blows too strong.  So wind power is not all that reliable either.  Hydroelectric power is more reliable.  But sometimes the rains don’t come.  And if there isn’t enough water behind a hydroelectric dam they have to take some generators offline.  For if they draw down the water level too much the water level behind the dam will be below the inlet to the turbines.  Which would shut off all the generators.

Of course, hydroelectric dams often have reservoirs.  These fill with water when the rains come.  So they can release their water to raise the water level behind a dam when the rains don’t come.  These reservoirs are, then, stored electric power.  For a minimal cost these can store a lot of electric power.  But it’s not an endless supply.  If there is a prolonged draught (or less snow in the mountains to melt and run off) even the water level in the reservoirs can fall too low to raise the water level behind the dam high enough to reach the water inlets to the turbines.

Storing electric power is something they can do with solar power, too.  Only it’s a lot more complex.  And a lot more costly.  Solar panels produce low DC currents and voltages.  Like small batteries in our flashlights.  So they have to have massive arrays of these solar panels connected together.  Like multiple batteries in a large flashlight.  They have to convert the DC power to AC power to connect it to the grid.  With some complicated and costly electronics.  And any excess power these solar arrays produce that they don’t feed into the grid they can store in a battery of batteries.  And as we know from the news on our electric cars, current battery technology does not hold a lot of charge.  Barely enough to drive a 75 mile round-trip.  So you’d need a lot of batteries to hold enough useful power to release into the grid after the sun goes down.

Storms like Sandy would wipe out Solar Arrays and Wind Farms with their High Winds and Storm Surges

When a 9.0 magnitude earthquake hit Japan in 2011 the Fukushima Daiichi Nuclear Power Plant suffered no damage.  Then the storm surge came.  Flooding the electrical equipment with highly conductive and highly corrosive seawater.  Shorting out and destroying that electrical equipment.  Shutting down the reactor cooling pumps.  Leading to a partial reactor core meltdown.  Proving what great damage can result when you mix water and electric equipment.  Especially when that water is seawater.

Hurricane Sandy hammered the Northeastern seaboard.  High winds and a storm surge destroyed cities and neighborhoods, flooded subway tunnels and left tens of millions of people without power.  And they may be without power for a week or more.  Restoring that power will consist primarily of fixing the electric grid.  To reconnect these homes and businesses to the power plants serving the electric grid.  They don’t have to build new power plants.  Now if these areas were powered by solar and wind power it would be a different story.  First of all, they would have lost power a lot earlier as the driving rains and cloud cover would have blocked out most of the sun.  The high winds would have taken the windmills offline.  For they shut down automatically when the winds blow too hard to prevent any damage.  Of course, the high winds and the storm surge would probably have damaged these as well as the power lines.  While shorting out and destroying all of that electronic equipment (to convert the DC power to AC power) and the battery storage system

So instead of just installing new power lines they would have to install new windmills, solar arrays, electronic equipment and storage batteries.  Requiring long manufacturing times.  Then time to transport.  And then time to install.  At a far greater cost than just replacing downed wires.  Leaving people without electric power for weeks.  Perhaps months.  Or longer.  This is why using coal-fired power plants is the best way to generate electric power.  They’re less costly.  Less fragile.  And less complicated.  You just don’t need such a large generating infrastructure.  Whereas solar arrays and wind farms would cover acres of land.  And water (for the wind farms).  And storms like Sandy could wipe these out with their high winds and storm surges.

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Coal Mines, Steam Engine, Electric Motor, Coal-Fired Power Plants, Water Pumps, Ventilation Fans, Strip Mining, Draglines and Coal Washing

Posted by PITHOCRATES - September 12th, 2012

Technology 101

The Steam Engine pumped Water from Mines allowing them to go Deeper as they followed Veins of Coal

Petroleum is the lifeblood of advanced economies.  It propels our airplanes, ships, trains, trucks, ambulances, air ambulances, fire trucks, cars, etc.  It moves everything.  Our sick and injured.  Our families.  Our food.  Our goods.  The raw materials that build the world we live in.  You would not recognize the world if we removed petroleum from it.  There would be no aviation.  No emergency vehicles that could respond in minutes.  No family car.  But we could still have ships and trains.  Because before petroleum there was coal.

Before the Industrial Revolution we used animals to move people and things.  We were using fuels for other things.  But not to move people and goods.  Until there was a problem getting that fuel.  The British were mining coal near the coast.  But there was a problem.  As the coal veins they mined moved under the sea they filled with water.  Limiting how far they could follow those veins.  They had a pump.  Driven by a crude steam engine.  But it just didn’t do the job very well.  Until a man came along and improved it.  James Watt.  Who improved that crude steam engine.  And changed the world.

The steam engine pumped water from coal mines allowing them to go deeper as they followed veins of coal.  But the steam engine had other uses.  They could power a drive shaft in a factory.  Allowing us to build factories anywhere.  Not just by moving water that drove a waterwheel.  And using a steam engine to move a train allowed us to connect these factories with other factories.  And to the stores in the cites that bought the things they built.  Steam-powered tractors replaced the horse and plow on the farm.  While steam locomotives brought coal from distant coal mines to our homes we burned for heat.  Coal was everywhere.  We had a coal-based economy.  And a coal-based life.  The more we used the more we had to mine.  Thanks to the coal-fired steam engine we could mine a lot of it.  And did.  It powered the Industrial Revolution.  And powers our modern economy today.  Because coal even powers the engines that replaced the steam engines in our factories.

The two largest Electrical Loads in a Coal Mine are the Water Pumps and the Ventilation Fans

We’ve replaced the steam engines in our factories with the electric motor.  Instead of having a main drive shaft through the factory and a system of belts and pulleys we put an electric motor at each workstation.  And connected it to the electric grid.  Greatly increasing our productivity.  And the electric power to drive these electric motors came predominantly from coal-fired power plants.  Coal has never been more important in the modern economy.  It provides about half of all electric power.  Followed by natural gas and nuclear power at about 20% each (though natural gas is on the rise).  Hydroelectric dams provide less than 10% of our electric power.  And everything else provides less than 5%.

Just as the steam engine made mining more efficient so did electric power.  Mines can go deeper because electric pumps can more efficiently pump water out of the mines.  And large fans can circulate the air underground so miners can breathe.  As well as disperse any buildups of methane gas or coal dust.  Before they can explode.  Which is one of the hazards of mining a flammable and, at times, explosive material.  The hazard is so real that you will not find ventilation fans inside the mine.  You’ll find water pumps deep in the mines.  But not the ventilation fans.  Because if there is a fire or an explosion underground they’ll need to protect those fans from damage so they will still be able to ventilate the mine.  For if the mine fills with smoke surviving a fire or an explosion will matter little if you cannot breathe.

The two largest electrical loads in a coal mine are the water pumps and the ventilation fans.  Mines consume enormous amounts of electric power.  And most of it goes to fighting the water seepage that will fill up a mine if not pumped out.  And making the mines habitable.  Electric power also runs the hoists that haul the coal to the surface.  Transports miners to and from the mines.  And runs the mining equipment in a confined space without any hazardous fumes.  As critical as this electric power is to survive working in such an unfriendly environment more times than not the power they use comes from a coal-fired power plant.  A plant they feed with the very coal they mine.  Because it’s dependable.  That electric power will always be there.

Coal will always let you Charge your Electric Car Overnight and Surf the Web in the Morning

But we just don’t mine coal underground.  We also dig it up from the surface.  With strip mining.  Most of the coal we use today comes from great strip mines out West.  Where they use mammoth machines called draglines to scrape away soil to get to the coal.  And then they scrape out the coal.  These machines are as big as ships and actually have crew quarters inside them.  They even name them like ships.  They operate kind of like a fishing rod with a few minor differences.  Instead of a rod there is a boom.  Instead of nylon fishing line there is a steel cable up to two inches in diameter.  And instead of a hook there is a bucket big enough to hold a 2-car garage.  The operator ‘throws’ the bucket out by running it out along the boom.  Then drops it in the dirt.  Then drags the bucket back.  The massive scale of the dragline requires an enormous amount of power.  And the power of choice?  Electric power.  Often produced by the very coal they mine.  Some of these machines have electric cables even bigger around than the cables that drag their buckets.  At voltages of 10,000 to 25,000 volts.  Drawing up to 2,000 amps.

These draglines can mine a lot of coal.  But it’s a lower-quality coal than some of our eastern coal.  Which has a higher energy content.  But eastern coal also has a higher sulfur content.  Which requires more costs to make it burn cleaner.  In fact, before any coal ships today we wash it to remove slate as well as other waste rock from the coal.  And it is in this waste rock where we find much of the sulfur.  So the washing makes the coal burn cleaner.  As well as raise the energy content for a given quantity of coal by removing the waste that doesn’t burn.  There are a few ways they do this.  But they all involve water.  Therefore, at the end of the process they have to dry the coal by spinning it in a large cylindrical centrifuge.  So a lot happens to coal between digging it out of the ground and loading it on a unit train (a train carrying only one type of cargo) bound to some power plant.  And chances are that it will go to a power plant.  For our coal-fired power plants buy about 80% or so of all coal mined.  So if you see a coal train it is probably en route to a coal-fired power plant.

Coal created the modern world.  And it powers it to this day.  From the first steam engines that dewatered mines to the coal-fired power plants that power the massive server farms that hold the content of the World Wide Web.  Yes, coal even powers the Internet.  As well as our electric cars.  For only coal will be able to meet the electric demand when everyone starts plugging their car into the electric grid overnight.  Because solar power doesn’t work at night.  And wind power is even less reliable.  For if it’s a still night you’ll have no charge to drive to work in the morning.  But if you plugged into coal you’ll always be able to charge your electric car overnight.  And surf the web in the morning.

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