Things that Absorb Energy can Cool Things Down and Things that Radiate Energy can Warm Things Up
When two different temperatures come into contact with each other they try to reach equilibrium. The warmer temperature cools down. And the cooler temperature warms up. If you drop some ice cubes into a glass of soda at room temperature the warm soda cools down. The ice cubes warm up. And melt. When there is no more ice to melt the temperature of the soda rises again. Until it reaches the ambient room temperature. The normal unheated or un-cooled temperature in the surrounding space. As the soda and the air in the room reach equilibrium.
When two temperatures come into contact with each other what happens depends on the available energy. Higher temperatures have more energy. Lower temperatures have less energy. For heat is energy. Things that absorb energy can cool things down. Things that radiate energy can warm things up. And this is the basis of our heating and cooling systems in our buildings and homes.
Boilers burn fuel to heat water. A furnace burns fuel to heat air. The heated water temperature and heated air temperature is warmer than the temperature you set on your thermostat. When this very hot water/air circulates through a house or building it comes into contact with the cooler air. As they come into contact with each other they bring the air in the space up to a comfortable room temperature. Above the unheated ambient temperature. But below the very hot temperature of the heating hot water or heated air temperature.
Heating and Cooling Buildings consume up to Half of all Energy on the Planet
Large buildings have air handling units (AHU) that ventilate, heat and cool the building’s air. They’re big boxes (some big enough for grown men to walk in) with filter sections to clean the air. Coil sections that heat or cool the air as it blows through these coils. A supply and a return fan to blow air into the building via a network of air ducts. And to suck air out of the building through another network of air ducts. And a series of dampers (outside air, exhaust air and return air).
To keep the air quality suitable for humans we have to exhaust the breath we exhale from the building. And replace it with fresh air from outside of the building. This is what the dampers are for. The amount they open and close adjusts the amount of outside air the AHU pulls into the building. The amount of the air it exhausts from the building. And the amount of air it recirculates within the building. Elaborate computer control systems carefully adjust these damper positions. For the amount of moving air has to balance. If you exhaust less you have to recirculate more. Otherwise you may have dangerous high pressures build up that can damage the system.
It takes a lot of energy to do this. Buildings consume up to half of all energy on the planet. And heating and cooling buildings is a big reason why. Because it take a lot of energy to raise or lower a building’s air temperature. And keeping the air safe for humans to breathe adds to that large energy consumption. If you stand outside next to an exhaust air damper you can understand why. If it’s winter time the exhausted air is toasty warm. If it’s summer time the exhausted air is refreshingly cool.
An Energy Recovery Wheel is a Circular Honeycomb Matrix that Rotates through both the Outside & Exhaust Air Ducts
In the winter large volumes of gas fire boilers to heat water. Electric water pumps send this water throughout the building. Into baseboard convection heaters under exterior windows to wash this cold glass with warm air. And into the heating coils on AHUs. Powerful electric supply and return fans blow air through those heating coils and throughout the building. After traveling through the supply air ductwork, out of the supply air ductwork and into the open air, back into the return air ductwork and back to the AHU much of this air exhausts out of the building. That returning air is not as warm as the supply air coming off of the heating coil. But it is still warm. And exhausting it out of the building dumps a lot of energy out of the building that requires new energy to heat very cold outside air to replace it. The more air you recirculate the less money it costs to heat the building. But you can only recirculate air so long before you compromise the quality of indoor air. So you eventually have to exhaust heated air and pull in more unheated outside air.
Enter the heat recovery unit. Or energy recovery unit. There are different names. And different technologies. But they do pretty much the same thing. They recover the energy in the exhaust air BEFORE it leaves the building. And transfers it to the outside air coming into the building. To understand how this works think of the outside air duct and the exhaust air duct running side by side. With the air moving in opposite directions. Like a two-lane highway. These sections of duct run between the AHU and the outside air and exhaust air dampers. It is in this section of ductwork where we put an energy recovery unit. Like an energy recovery wheel. A circular honeycomb matrix that slowly rotates through both ducts. Half of the wheel is in the outside air duct. Half of the wheel is in the exhaust air duct. As exhaust air blows through the honeycomb matrix it absorbs heat (i.e., energy) from the exhaust air stream. As that section of the wheel rotates into the outside air duct the unheated outside air blows through the now warm honeycomb matrix. Where the unheated air absorbs the energy from the wheel. Warming it slightly so the AHU doesn’t have use as much energy to heat outside air. It works similarly with air conditioned air.
Many of us no doubt heard our mother yell, “Shut the door. You’re letting all of the heat out.” For whenever you open a door heated air will vent out and cold air will migrate in. Making it cooler for awhile until the furnace can bring the temperature back up. It’s similar with commercial buildings. Which is why a lot of them have revolving doors. So there is always an airlock between the heated/cooled air inside and the air outside. But engineers do something else to keep the cold/hot/humid air outside when people open doors. They design the AHU control system to maintain a higher pressure inside the building than there is outside of the building. So when people open doors air blows out. Not in. This keeps cold air from leaking into the building. Allowing people to work comfortably near these doors without getting a cold blast of air whenever they open. It allows people to work along exterior windows and walls without feeling any cold drafts. And it also helps to keep any bad smells from outside getting into the building.
Tags: absorb energy, AHU, air handling unit, air quality, boiler, cooling, damper, ductwork, energy, energy recovery unit, energy recovery wheel, equilibrium, exhaust air, furnace, heat, heat recovery unit, heating, heating coil, heating hot water, honeycomb matrix, outside air, pump, radiate energy, return, return-air, supply, temperature
(Original published December 21st, 2011)
A Waterwheel, Shaft, Pulleys and Belts made Power Transmission Complex
The history of man is the story of man controlling and shaping our environment. Prehistoric man did little to change his environment. But he started the process. By making tools for the first time. Over time we made better tools. Taking us into the Bronze Age. Where we did greater things. The Sumerians and the Egyptians led their civilization in mass farming. Created some of the first food surpluses in history. In time came the Iron Age. Better tools. And better plows. Fewer people could do more. Especially when we attached an iron plow to one horsepower. Or better yet, when horses were teamed together to produce 2 horsepower. 3 horsepower. Even 4 horsepower. The more power man harnessed the more work he was able to do.
This was the key to controlling and shaping our environment. Converting energy into power. A horse’s physiology can produce energy. By feeding, watering and resting a horse we can convert that energy into power. And with that power we can do greater work than we can do with our own physiology. Working with horse-power has been the standard for millennia. Especially for motive power. Moving things. Like dragging a plow. But man has harnessed other energy. Such as moving water. Using a waterwheel. Go into an old working cider mill in the fall and you’ll see how man made power from water by turning a wheel and a series of belts and pulleys. The waterwheel turned a main shaft that ran the length of the work area. On the shaft were pulleys. Around these pulleys were belts that could be engaged to transfer power to a work station. Where it would turn another pulley attached to a shaft. Depending on the nature of the work task the rotational motion of the main shaft could be increased or decreased with gears. We could change it from rotational to reciprocating motion. We could even change the axis of rotation with another type of gearing.
This was a great step forward in advancing civilization. But the waterwheel, shaft, pulleys and belts made power transmission complex. And somewhat limited by the energy available in the moving water. A great step forward was the steam engine. A large external combustion engine. Where an external firebox heated water to steam. And then that steam pushed a piston in a cylinder. The energy in expanding steam was far greater than in moving water. It produced far more power. And could do far more work. We could do so much work with the steam engine that it kicked off the Industrial Revolution.
Nikola Tesla created an Electrical Revolution using AC Power
The steam engine also gave us more freedom. We could now build a factory anywhere we wanted to. And did. We could do something else with it, too. We could put it on tracks. And use it to pull heavy loads across the country. The steam locomotive interconnected the factories to the raw materials they consumed. And to the cities that bought their finished goods. At a rate no amount of teamed horses could equal. Yes, the iron horse ended man’s special relationship with the horse. Even on the farm. Where steam engines powered our first tractors. Giving man the ability to do more work than ever. And grow more food than ever. Creating greater food surpluses than the Sumerians and Egyptians could ever grow. No matter how much of their fertile river banks they cultivated. Or how much land they irrigated.
Steam engines were incredibly powerful. But they were big. And very complex. They were ideal for the farm and the factory. The steam locomotive and the steamship. But one thing they were not good at was transmitting power over distances. A limitation the waterwheel shared. To transmit power from a steam engine required a complicated series of belts and pulleys. Or multiple steam engines. A great advance in technology changed all that. Something Benjamin Franklin experimented with. Something Thomas Edison did, too. Even gave us one of the greatest inventions of all time that used this new technology. The light bulb. Powered by, of course, electricity.
Electricity. That thing we can’t see, touch or smell. And it moves mysteriously through wires and does work. Edison did much to advance this technology. Created electrical generators. And lit our cities with his electric light bulb. Electrical power lines crisscrossed our early cities. And there were a lot of them. Far more than we see today. Why? Because Edison’s power was direct current. DC. Which had some serious drawbacks when it came to power transmission. For one it didn’t travel very far before losing much of its power. So electrical loads couldn’t be far from a generator. And you needed a generator for each voltage you used. That adds up to a lot of generators. Great if you’re in the business of selling electrical generators. Which Edison was. But it made DC power costly. And complex. Which explained that maze of power lines crisscrossing our cities. A set of wires for each voltage. Something you didn’t need with alternating current. AC. And a young engineer working for George Westinghouse was about to give Thomas Edison a run for his money. By creating an electrical revolution using that AC power. And that’s just what Nikola Tesla did.
Transformers Stepped-up Voltages for Power Transmission and Stepped-down Voltages for Electrical Motors
An alternating current went back and forth through a wire. It did not have to return to the electrical generator after leaving it. Unlike a direct current ultimately had to. Think of a reciprocating engine. Like on a steam locomotive. This back and forth motion doesn’t do anything but go back and forth. Not very useful on a train. But when we convert it to rotational motion, why, that’s a whole other story. Because rotational motion on a train is very useful. Just as AC current in transmission lines turned out to be very useful.
There are two electrical formulas that explain a lot of these developments. First, electrical power (P) is equal to the voltage (V) multiplied by the current (I). Expressed mathematically, P = V x I. Second, current (I) is equal to the voltage (V) divided by the electrical resistance (R). Mathematically, I = V/R. That’s the math. Here it is in words. The greater the voltage and current the greater the power. And the more work you can do. However, we transmit current on copper wires. And copper is expensive. So to increase current we need to lower the resistance of that expensive copper wire. But there’s only one way to do that. By using very thick and expensive wires. See where we’re going here? Increasing current is a costly way to increase power. Because of all that copper. It’s just not economical. So what about increasing voltage instead? Turns out that’s very economical. Because you can transmit great power with small currents if you step up the voltage. And Nikola Tesla’s AC power allowed just that. By using transformers. Which, unfortunately for Edison, don’t work with DC power.
This is why Nikola Tesla’s AC power put Thomas Edison’s DC power out of business. By stepping up voltages a power plant could send power long distances. And then that high voltage could be stepped down to a variety of voltages and connected to factories (and homes). Electric power could do one more very important thing. It could power new electric motors. And convert this AC power into rotational motion. These electric motors came in all different sizes and voltages to suit the task at hand. So instead of a waterwheel or a steam engine driving a main shaft through a factory we simply connected factories to the electric grid. Then they used step-down transformers within the factory where needed for the various work tasks. Connecting to electric motors on a variety of machines. Where a worker could turn them on or off with the flick of a switch. Without endangering him or herself by engaging or disengaging belts from a main drive shaft. Instead the worker could spend all of his or her time on the task at hand. Increasing productivity like never before.
Free Market Capitalism gave us Electric Power, the Electric Motor and the Roaring Twenties
What electric power and the electric motor did was reduce the size and complexity of energy conversion to useable power. Steam engines were massive, complex and dangerous. Exploding boilers killed many a worker. And innocent bystander. Electric power was simpler and safer to use. And it was more efficient. Horses were stronger than man. But increasing horsepower required a lot of big horses that we also had to feed and care for. Electric motors are smaller and don’t need to be fed. Or be cleaned up after, for that matter.
Today a 40 pound electric motor can do the work of one 1,500 pound draft horse. Electric power and the electric motor allow us to do work no amount of teamed horses can do. And it’s safer and simpler than using a steam engine. Which is why the Roaring Twenties roared. It was in the 1920s that this technology began to power American industry. Giving us the power to control and shape our environment like never before. Vaulting America to the number one economic power of the world. Thanks to free market capitalism. And a few great minds along the way.
Tags: AC, AC power, alternating current, belts, belts and pulleys, better tools, capitalism, controlling and shaping our environment, converting energy into power, copper wire, current, DC, DC power, direct current, Edison, electric, electric motors, electrical generators, electrical power, electrical power lines, electrical resistance, electricity, energy, energy conversion, engine, factories, factory, free market, free-market capitalism, generator, horse, horsepower, light bulb, motors, moving water, Nikola Tesla, plow, power, power lines, power transmission, pulleys, reciprocating engine, reciprocating motion, resistance, Roaring Twenties, rotational motion, steam, steam engine, steam locomotive, Tesla, Thomas Edison, tools, transformers, voltage, waterwheel, work
Week in Review
That carbon tax is so popular in Australia that they are buying television ads to explain how good it is. Good for the environment. And good for the consumer. As they get a cleaner environment. Not a bad deal considering the only people paying these carbon taxes are those filthy, polluting electricity producers. And they deserve to pay this tax as a penalty for polluting the environment (see More costly carbon tax ads set for TV by Andrew Tillett Canberra posted 10/18/2012 on The West Australian).
A fresh round of carbon tax compensation TV advertisements could hit the airwaves, a Senate Estimates committee has heard.
Bureaucrats from the Department of Families, Housing, Community Services and Indigenous Affairs told the hearing this morning a third phase of the campaign was being considered.
The first series of ads began in May and controversially failed to mention that extra payments going to households were to compensate them for higher living costs caused by the carbon tax.
Then again, it is the consumers that have to pay the higher electric rates those carbon taxes cause by increasing the cost to the electricity producers. So they take a lot of wealth from the electric utilities. Throw a little to the consumer stuck paying the higher electric rates to shut them up. Sort of forget to tell them that it was their fault for those higher rates in the first place. And use the rest to pay for their out of control government spending. Which is what a carbon tax is for. Because in this day and age with developed economies and welfare states it costs a whole lot more than it once did to buy votes.
Governments love taxing energy because people simply cannot live without consuming energy. Which is why the US had their cap and trade (though they failed to implement it. So far). The Europeans have their emissions trading scheme. And the Australians have their carbon tax. Which are all just more elaborate ways to transfer wealth from the private sector to the public sector. And has nothing to do with reducing carbon emissions.
Tags: Australia/New Zealand, carbon tax, electricity, energy, government spending, higher electric rates
We use Diesel Fuel in our Ships, Trains and Trucks to move Food from the Farm to the Grocery Store
People don’t like high gas prices. When the price at the pump goes up more of our paycheck goes into the gas tank. Or, more precisely, in everyone’s gas tanks. For even if you don’t drive a car when gas prices go up you’re putting more of your paycheck into the gas tanks of others. Thanks to oil being the lifeblood of our economy. And unless you’re completely self-sufficient (growing your own food, making your own clothes, etc.) everything you buy consumed some petroleum oil somewhere before reaching you.
Gas prices go up for a variety of reasons. The purely economic reason is the market forces of supply and demand. When gas prices rise it’s because demand for gasoline is greater than the supply of gasoline. Which means our refineries aren’t producing enough gasoline to meet demand. And the purely economic reason for that is that they are not refining enough crude oil. Meaning the low supply of gasoline is due to the low supply of crude oil. Which brings us to how high gasoline prices consume more of our paychecks even if we don’t drive. The reason being that we just don’t make gasoline out of crude oil. We also make diesel fuel.
Diesel fuel is a remarkable refined product. It just has so much energy in it. And we can compress an air-fuel mixture of it to a very small volume. Put the two together and you get a long and powerful power stroke. Making the diesel engine the engine of choice for our heavy moving. We use it in the ships that cross the ocean. In the trains that cross our continents. And in the trucks that bring everything to where we can buy them. To the grocery stores. The department stores. To the restaurants. Everything in the economy that we don’t make for ourselves travels on diesel fuel. Which is why when gas prices go up diesel fuel prices go up. Because of the low supply of oil going to our refineries to refine these products.
Oil is at a Disadvantage when it comes to Inflation because you just can’t Hide the Affects of Inflation in the Price of Oil
And there are other things that raise the price of gasoline. That aren’t purely economical. But more political. Such as restrictions on domestic oil drilling. Which reduces domestic supplies of crude oil. Political opposition to new pipelines. Which reduces Canadian supplies of crude oil. Special ‘summer’ blends of gasoline to reduce emissions that tax a refinery’s production capacity. As well as our pipeline distribution network. Higher gasoline taxes. To pay for roads and bridges. And to battle emissions. The ethanol mandate to use corn for fuel instead of food. Again, to battle emissions. All of which makes it more difficult to bring more crude oil to our refineries. And more difficult for our refineries to make gasoline. Which all go to adding costs into the system. Raising the price at the pump. Consuming more of our paychecks. No matter who is buying it.
Then there is another factor increasing the price at the pump. Inflation. When the government tries to stimulate economic activity by lowering interest rates they do that by expanding the money supply. So money is cheaper to borrow because there is so much more of it to borrow. Hence the lower interest rates. However, expanding the money supply also causes inflation. And devalues the dollar. As more dollars are now chasing the same amount of goods and services in the economy. So it takes more of them to buy the same things they once did. One of the harder hit commodities is oil. Because we price oil on the world market in U.S. dollars. So when you devalue the dollar it takes more of them to buy the same amount of oil they once bought.
Oil is at a particular disadvantage when it comes to inflation. Because you just can’t hide the affects of inflation in the price of oil. Or the gas we make from it. Unlike you can with laundry detergent, potato chips, cereal, candy bars, toilet paper, etc. Where the manufacturer can reduce the packaging or portion size. Allowing them not to raise prices to reflect the full impact inflation. They still increase the unit price to reflect the rise in the general price level. But by selling smaller quantities and portions their prices still look affordable. This is a privilege the oil industry just doesn’t have. They price crude oil by a fixed quantity (barrel). And sell gasoline by a fixed quantity (gallon). So they have no choice but to reflect the full impact of inflation in these prices. Which is why there is more anger about high gas prices than almost any other commodity.
Perhaps we can lay the Greatest Blame for the Current Economic Malaise on the Government’s Inflationary Monetary Policies
Current gas prices are hitting record highs. And this during the worse economic recovery following the worst recession since the Great Depression. Gas prices and the unemployment rate are typically inversely related to each other. When there is high unemployment people are buying less gasoline. This excess gasoline supply results in lower gas prices. When there is low unemployment people are buying more gasoline. This excess demand for gasoline results in higher gas prices. These are the normal affects of supply and demand. So the current high gas prices have little to do to with normal economic forces. Which leaves government policies to explain why gas prices are so high.
Environmental concerns have greatly increased regulatory policy. Increasing regulatory compliance costs. Which has greatly discouraged the building of new refineries. And making it very difficult to build new pipelines. Which tax current pipeline and refinery capacities. A problem mitigated only with their restriction on domestic oil production. The current administration has pretty much shut down oil exploration and production on all federal lands. Reducing crude oil supplies to refineries. These environmental policies would send gas prices soaring if the economy was booming. But the economy is not booming. In fact the U-6 unemployment rate (which counts everyone who can’t find a full time job) held steady at 14.7% in September. So an overheated economy is not the reason we have high gas prices. But the high gas prices may be part of the reason we have such high unemployment.
Perhaps we can lay the greatest blame for the current economic malaise on the government’s inflationary monetary policies. Inflation increases prices. Especially those things sold in fixed quantities priced in dollars. Like oil. And gasoline. The price inflation in refined oil products is like a virus that spreads throughout the economy. Because everyone uses energy. Especially the food industry. From the farmers driving their tractor to work their fields. To the trucks that take grain to rail terminals. To the trains that transport this grain to food processing plants. To the trucks that deliver these food products to our grocery stores. From the moment farmers first turn over their soil in spring to the truck backing into to a grocery store’s loading dock to consumers bringing home groceries in their car to put food on the table fuel is consumed everywhere. Which is why when gasoline prices go up food prices go up. Because we refine gasoline from the same crude oil we refine diesel fuel from. Oil. Creating a direct link between our energy policy and the price of food.
Tags: crude oil, devalue the dollar, diesel, diesel engine, diesel fuel, dollar, domestic oil drilling, domestic supplies of crude oil, economic activity, emissions, energy, environmental policies, food prices, gas prices, gasoline, high food prices, high gas prices, inflation, inflationary monetary policies, interest rates, money supply, oil, petroleum oil, pipeline, price at the pump, price of gasoline, prices, refineries, refining, ships, supply and demand, trains, trucks, unemployment, unemployment rate
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.
Tags: advanced economies, bucket, Coal, coal mines, coal veins, coal washing, coal-fired power plants, coal-fired steam engine, draglines, eastern coal, electric car, electric grid, electric motor, electric power, energy, energy content, Industrial Revolution, miners, mining coal, power plants, pumps, steam engine, strip mining, sulfur, sulfur content, ventilation fans, water pumps
We started the First Cars with a Hand Crank and Nearly Broke an Arm if the Hand Crank Kicked Back
The king of car engines is the internal combustion engine (ICE). We tried other motors such as a steam engine. But a steam engine is a heat engine. Meaning it first has to get hot enough to boil water into steam. Which meant any trip in a car took a little extra time to bring the boiler up to operating temperatures. Boilers tend to be big and heavy. And dangerous. Should something happen and a dangerous level of steam pressure built up they could explode. Despite those drawbacks, though, a steam engine-powered car took you places. And as long as there was fuel for the firebox and water for the boiler you could keep driving.
Another engine we tried was the electric motor. These didn’t have any of the drawbacks of a steam engine. You didn’t have to wait for a boiler to get to operating temperatures before driving. Nothing was in danger of exploding. An electric motor was lighter than a cast-iron boiler. And an electric motor could make a car zip along. However, an electric motor requires continuous electricity to operate. Provided by charged batteries. Which didn’t last long. And took hours to recharge. Giving the electric car limited range. And little convenience. For the heavier it was and/or the faster you went the faster you drained those batteries. Which could be a problem taking the family on vacation. But they worked well in a forklift on a loading dock. Because of the battery-power they produced no emissions so they’re safe to use indoors. They had limited auxiliary systems to run (other than a horn and maybe a light). And when they were running low on charge you rarely needed to drive more than 20 or 30 feet to a charging station.
The first ICE-powered cars took some manly strength to operate. They didn’t have power brakes, power steering, automatic transmissions or starters. We started the first ICE-powered cars with a hand crank. That took a lot of strength to turn. And if it backfired while starting the kick of the handle could easily break a wrist or an arm. Putting a damper on any Sunday afternoon drive. This limited the spread of the automobile. They were complex machines that required some strength to operate. And they could be very dangerous. Then along came the electric starter. Which was an electric motor that spun the ICE to life. Making the car much safer to start. Expanding the popularity of the automobile. For there was no longer a good chance that you could break your arm trying to start it. And through the years came all those accessories making it easier and more comfortable to drive. Today automatic transmissions, power steering, power brakes, headlights, interior lights, power locks, power windows, powered seats, a fairly decent audio system, heat, air conditioning and more are standard on most cars. All effortless powered by that internal combustion engine.
Current Battery Technology does not give the All-Electric Car a Great Range
The reason why an ICE can do all of this is because gasoline is a very concentrated energy source. It doesn’t take a lot of it to go a long way. And it can accelerate you up a hill. It even has the energy to pass someone on a hill. It’s a fuel source we can take with us. A small amount of it stores conveniently and safely in a gas tank slung underneath a car. And when it’s empty it takes very little time to refill. A ten minute stop at a gas station and you’re back on the road able to drive another 500 miles or so. Even in the dark of night with headlights blazing. While keeping toasty warm in the winter. Or comfortably cool in the summer. Things an electric battery just can’t do. So why would we even want to trade one for the other? In a word—emissions.
The internal combustion engine pollutes. The more fuel a car burns the more it pollutes. So to cut pollution you try to make cars burn less fuel. You increase the fuel economy. And you can do that in a couple of ways. You can cut the weight of the vehicle. And put in a smaller engine. Because a smaller engine can power a lighter car. But a smaller car carries fewer people comfortably. And can carry less stuff. A motor cycle gets very good fuel economy but you can’t take the family on a Sunday drive on one. And you can’t pack up your things on a motorcycle when going off to college. So the tradeoff between fuel economy and weight has consequences.
An electric car does not pollute. At all. (Though the power plant that charges its batteries does pollute. A lot.) But current battery technology does not give the all-electric car a great range. Typically coming in at less than 75 miles per charge. Which is great if you’re operating a forklift on a loading dock. But it’s pretty bad if you’re actually driving on a road going someplace. And hope to return. The heavier the car is the shorter that driving range. If you want to use your headlights, heater or air conditioner it’ll be shorter still. On top of this short range recharging your battery isn’t like stopping at the gas station for 10 minutes. No. What one typically does is pray that he or she gets home. Then plugs in. And by morning the car would be fully charge for another 75 miles or so of driving.
To Maximize the Benefit of a Hybrid you’d want to Carry the Absolute Minimum of Batteries to Serve your Needs
So all-electric cars are clean but they won’t really take us places. The ICE-powered car will take us places but it’s not really clean. Enter the gas/electric hybrid. Which combines the best of the all-electric car (clean) and the best of the ICE-powered car (range). There are a few varieties. The parallel hybrid has both an ICE and an electric motor connected to a transmission that powers the wheels. The ICE also drives a small generator. Batteries power the electric motor. And a gas tank feeds the ICE. The generator keeps the batteries charged. The battery powers the electric motor to accelerate the car from a stop. After a certain speed the small ICE takes over. When the car needs to accelerate the electric motor assists the ICE. The small ICE has excellent fuel economy thus reducing emissions. The electric motor/battery provides the additional horsepower when needed to compensate for an undersized ICE. And the gasoline-powered engine provides extended range.
In addition to the parallel hybrid there is the series hybrid. It has the same parts but they are connected differently. The series hybrid is more like a diesel-electric locomotive. Gasoline feeds the ICE. The ICE drives a generator. The generator charges the batteries and/or drives the electric motor. The electric motor drives a transmission that spins the wheels. This car drives on batteries until the charge runs out and then switches over to the ICE. For short commutes this provides excellent fuel economy. For longer drives (well over 75 miles or so) it’s more like a standard ICE-powered car with a roundabout way of turning the wheels.
Then there’s the plug-in variety. In addition to all of the above you can plug your car into a charger to further save on gasoline use and reduce emissions (produced by the car; not by the electric power plant). Letting you recharge the battery overnight in a standard 120V outlet. In a slightly shorter time with a 240 volt outlet. And quicker still in a 480 volt outlet. If your commute to and from work is 50 miles or less you can probably charge up at home and not have to carry a charger with you (to convert the AC power to the DC power of the batteries). Saving even more weight. But if you plan on charging on the road you’ll need to carry a charger with you. Adding additional weight. Which will, of course, reduce your battery range. Also, you can adjust the number of batteries to match your typical daily commute. The shorter your commute the less charge you need to store. Which lets you get by on fewer batteries. Greatly reducing the weight of the car (and extending your battery range). A gallon of gas weighs about 7 pounds and can take a car 30 miles or more. You would need about 1,000 pounds of batteries to provide a similar range. So range doesn’t come cheap. To maximize the benefit of a hybrid you’d want to carry the absolute minimum of batteries to serve your needs. Knowing that if you got a new job with a longer commute you could rely on the ICE in your hybrid to get you to work and back home safe again.
Tags: air conditioning, all-electric car, automobile, batteries, car, charge, charger, electric motor, electric starter, emissions, energy, fuel, fuel economy, gasoline, generator, headlights, heat, ICE, internal combustion engine, limited range, parallel hybrid, plug-in, range, recharging, series hybrid, steam engine
Roller Coasters use Gravity to Convert Energy back and forth between Potential Energy and Kinetic Energy
We cannot destroy energy. All we can do is convert it. It’s a law of physics. The law of conservation of energy. A roller coaster shows this. Where roller coasters move by converting potential energy into kinetic energy. And then by converting kinetic energy back into potential energy.
The best roller coasters race down tall inclines gaining incredible speed. The taller the coaster the faster the speed. That’s because of potential energy (stated in units of joules). Which is equal to the mass times the force of gravity times the height. The last component is what makes tall roller coasters fast. Height. As the cars inch over the summit gravity begins pulling them down. And the longer gravity can pull them down the more speed they can gain. At the bottom of the hill the height is zero so the potential energy is zero. All energy having been converted into kinetic energy (also stated in units of joules).
Roller coasters travel the fastest at the lowest points in the track. Where potential energy equals zero. While kinetic energy is at its highest. Which is equal to one half times the mass times the velocity squared. So the higher the track the more time gravity has to accelerate these cars. At their fastest speed they start up the next incline. Where the force of gravity begins to pull on them. Slowing them down as they climb up the next hill. Converting that kinetic energy back into potential energy. When they crest the hill for a moment their speed is zero so their kinetic energy is zero. All energy having been converted back into potential energy. Where gravity tugs those cars down the next incline. And so on up and down each successive hill. Where at all times the sum of potential energy and kinetic energy equals the same amount of joules. Maximum potential energy is at the top. Maximum kinetic energy is at the bottom. And somewhere in the middle they each equal half of their maximum amounts.
(This is a simplified explanation. Additional forces are ignored for simplicity to illustrate the relation between potential energy and kinetic energy.)
We build Dams on Rivers to do what Niagara Falls does Naturally
So once over the first hill roller coasters run only on gravity. And the conversion of energy from potential to kinetic energy and back again. Except for that first incline. Where man-made power pulls the cars up. Electric power. Produced by generators. Spun by kinetic energy. Produced from the expanding gases of combustion in a natural gas-powered plant. Or from high-pressure steam produced in a coal-fired power plant or nuclear power plant. Or in another type of power plant that converts potential energy into kinetic energy. In a hydroelectric dam.
Using water power dates back to our first civilizations. Then we just used the kinetic energy of a moving stream to turn a waterwheel. These waterwheels turned shafts and pulleys to transfer this power to work stations. So they couldn’t spin too fast. Which wasn’t a problem because people only used rivers and streams with moderate currents. So these wheels didn’t spin fast. But they could turn a mill stone. Or run a sawmill. With far more efficiency than people working with hand tools. But there isn’t enough energy in a slow moving river or stream to produce electricity. Which is why we built some of our first hydroelectric power plants at Niagara Falls. Where there was a lot of water at a high elevation that fell to a lower elevation. And if you stick a water turbine in the path of that water you can generate electricity.
Of course, there aren’t Niagara Falls all around the country. Where nature made water fall from a high elevation to a low elevation. So we had to step in to shape nature to do what Niagara Falls does naturally. By building dams on rivers. As we blocked the flow of water the water backed up behind the dam. And the water level climbed up the river banks to from a large reservoir. Or lake. Raising the water level on one side of the dam much higher than the other side. Creating a huge pool of potential energy (mass times gravity times height). Just waiting to be converted into kinetic energy. To drive a water turbine. The higher the height of the water behind the dam (or the higher the head) the greater the potential energy. And the greater the kinetic energy of the water flow. When it flows.
Hydroelectric Power is the Cleanest and Most Reliable Source of Renewable Energy-Generated Power
Near the water level behind the dam are water inlets into channels through the dam or external penstocks (large pipes) that channels the water from the high elevation to the low elevation and into the vanes of the water turbine. The water flows into these curved vanes which redirects this water flow down through the turbine. Creating rotational motion that drives a generator. After exiting the turbine the water discharges back into the river below the dam.
Our electricity is an alternating current at 60 hertz (or cycles per second). These turbines, though, don’t spin at 60 revolutions per second. So to create 60 hertz they have to use different generators than they use with steam turbines. Steam turbines spin a generator with only one rotating magnetic field to induce a current in the stator (i.e., stationary) windings of the generator. They can produce an alternating current at 60 hertz because the high pressure steam can spin these generators at 60 revolutions per second. The water flowing through a turbine can’t. So they add additional rotational magnetic fields in the generator. Twelve rotational magnetic fields can produce 60 hertz of alternating current while the generator only spins at 5 revolutions per second. Adjustable gates open and close to let more or less water to flow through the turbine to maintain a constant rotation.
The hydroelectric power plant is one of the simplest of power generating plants. There is no fuel needed to generate heat to make steam. No steam pressure to monitor closely to prevent explosions. No fires to worry about in the mountains of coal stored at a plant. No nuclear meltdown to worry about. And no emissions. All you need is water. From snow in the winter that melts in the spring. And rain. Not to mention a good river to dam. If the water comes the necessary head behind the dam will be there to spin those turbines. But sometimes the water isn’t there. And the dams have to shut down generators because there isn’t enough water. But hydroelectric power is still the cleanest and most reliable source of electric power generated from renewable energy we have. But it does have one serious drawback. You need a river to dam. And the best spots already have a dam on them. Leaving little room for expansion of hydroelectric power. Which is why we generate about half of our electric power from coal. Because we can build a coal-fired power plant pretty much anywhere we want to. And they will run whether or not we have snow or rain. Because they are that reliable.
Tags: 60 hertz, alternating current, conservation of energy, dam, electric power, electricity, energy, generator, gravity, hydroelectric, hydroelectric dam, hydroelectric power, hydroelectric power plants, joules, kinetic energy, Niagara Falls, potential energy, power plants, reservoir, river, roller coaster, rotating magnetic field, steam turbines, water, water level, water turbine, waterwheel
By burning Coal to Boil Water into Steam to Move a Piston we could Build a Factory Anywhere
We created advanced civilization by harnessing energy. And converting this energy into working power. Our first efforts were biological. Feeding and caring for large animals made these animals strong. Their physiology converted food and water into strong muscles and bones. Allowing them to pull heavy loads. From plowing. To heavy transportation. To use in construction. Of course the problem with animals is that they’re living things. They eat and drink. And poop and pee. Causing a lot of pollution in and around people. Inviting disease.
As civilization advanced we needed more energy. And we found it in wind and water. We built windmills and waterwheels. To capture the energy in moving wind and moving water. And converted this into rotational motion. Giving us a cleaner power source than working animals. Power that didn’t have to rest or eat. And could run indefinitely as long as the wind blew and the water flowed. Using belts, pulleys, cogs and gears we transferred this rotational power to a variety of work stations. Of course the problem with wind and water is that you needed to be near wind and water. Wind was more widely available but less reliable. Water was more reliable but less widely available. Each had their limitations.
The steam engine changed everything. By burning a fuel (typically coal) to boil water into steam to move a piston we could build a factory anywhere. Away from rivers. And even in areas that had little wind. The reciprocating motion of the piston turned a wheel to convert it into rotational motion. Using belts, pulleys, cogs and gears we transferred this rotational power to a variety of work stations. This carried us through the Industrial Revolution. Then we came up with something better. The electric motor. Instead of transferring rotational motion to a workstation we put an electric motor at the work station. And powered it with electricity. Using electric power to produce rotational motion at the workstation. Electricity and the electric motor changed the world just as the steam engine had changed the world earlier. Today the two have come together.
You can tell a Power Plant uses a Scrubber by the White Steam puffing out of a Smokestack
Coal has a lot of energy in it. When we burn it this energy is transformed into heat. Hot heat. For coal burns hot. The modern coal-fired power plant is a heat engine. It uses the heat from burning coal to boil water into steam. And as steam expands it creates great pressure. We can use this pressure to push a piston. Or turn a steam turbine. A rotational device with fins. As the steam pushes on these fins the turbine turns. Converting the high pressure of the steam into rotational motion. We then couple this rotational motion of the steam turbine to a generator. Which spins the generator to produce electricity.
Coal-fired power plants are hungry plants. A large plant burns about 1,000 tons of coal an hour. Or about 30,000 pounds a minute. That’s a lot of coal. We typically deliver coal to these plants in bulk. Via Great Lakes freighters. River barges. Or unit trains. Trains made up of nothing but coal hopper cars. These feed coal to the power plants. They unload and conveyor systems take this coal and create big piles. You can see conveyors rising up from these piles of coal. These conveyors transport this coal to silos or bunkers. Further conveyor systems transfer the coal from these silos to the plant. Where it is smashed and pulverized into a dust. And then it’s blown into the firebox, mixed with hot air and ignited. Creating enormous amounts of heat to boil an enormous amount of water. Creating the steam to turn a turbine.
Of course, with combustion there are products left over. Sulfur impurities in the coal create sulfur dioxide. And as the coal burns it leaves behind ash. A heavy ash that falls to the bottom of the firebox. Bottom ash. And a lighter ash that is swept away with the flue gases. Fly ash. Filters catch the fly ash. And scrubbers use chemistry to remove the sulfur dioxide from the flue gases. By using a lime slurry. The flue gases rise through a falling mist of lime slurry. They chemically react and create calcium sulfate. Or Gypsum. The same stuff we use to make drywall out of. You can tell a power plant uses a scrubby by the white steam puffing out of a smokestack. If you see great plumes puffing out of a smokestack there’s little pollution entering the atmosphere. A smokestack that isn’t puffing out a plume of white steam is probably spewing pollution into the atmosphere.
Coal is a Highly Concentrated Source of Energy making Coal King when it comes to Electricity
When the steam exits the turbines it enters a condenser. Which cools it and lowers its temperature and pressure. Turning the steam back into water. It’s treated then sent back to the boiler. However, getting the water back into the boiler is easier said than done. The coal heats the water into a high pressure steam. So high that it’s hard for anything to enter the boiler. So this requires a very powerful pump to overcome that pressure. In fact, this pump is the biggest pump in the plant. Powered by electric power. Or steam. Sucking some 2-3 percent of the power the plant generates.
Coupled to the steam turbine is a power plant’s purpose. Generators. Everything in a power plant serves but one purpose. To spin these generators. And when they spin they generate a lot of power. Producing some 40,000 amps at 10,000 to 30,000 volts at a typical large plant. Multiplying current by power and you get some 1,200 MW of power. Which can feed a lot of homes with 100 amp, 240 volt services. Some 50,000 with every last amp used in their service. Or more than twice this number under typical loads. Add a few boilers (and turbine and generator sets) and one plant can power every house and business across large geographic areas in a state. Something no solar array or wind farm can do. Which is why about half of all electricity produced in the U.S. is generated by coal-fired power plants.
Coal is a highly concentrated source of energy. A little of it goes a long way. And a lot of it produces enormous amounts of electric power. Making coal king when it comes to electricity. There is nothing that can match the economics and the logistics of using coal. Thanks to fracking, though, natural gas is coming down in price. It can burn cleaner. And perhaps its greatest advantage over coal is that we can bring a gas-fired plant on line in a fraction amount of the time it takes to bring a coal-fired plant on line. For coal-fired plants are heat engines that boil water into steam to spin turbines. Whereas gas-fired plants use the products of combustion to spin their turbines. Utilities typically use a combination of coal-fired and gas-fired plants. The coal-fired plants run all of the time and provide the base load. When demand peaks (when everyone turns on their air conditioners in the evening) the gas-fired plants are brought on line to meet this peak demand.
Tags: ash, boil water, boiler, Coal, coal-fired power plant, combustion, electric motor, electric power, electricity, energy, fly ash, generator, heat, heat engine, lime slurry, power, pressure, rotational motion, scrubbers, steam, steam engine, steam turbine, sulfur dioxide, turbine, waterwheels, windmills
A Photocell basically works like a Light Emitting Diode (LED) in Reverse
Solar power is based on the same technology that that gave us the electronic world. Silicon. That special material in the periodic table that has four electrons in its valence (i.e., outer most) shell. And four holes that can accept an electron. Allowing it to form a perfect silicon crystal. When these silicon atoms come together their four valence electrons form covalent bonds with the holes in neighboring silicon atoms. These silicon atoms share their valence electrons so that each silicon atom now has a full valence shell of eight electrons (with four of their own electrons and four shared electrons). Making that perfect crystal structure. Which is pretty much useless in the world of semiconductors. Because you need free electrons to conduct electricity.
When we add impurities (called ‘doping’) to silicon is where the magic starts. If we add a little bit of an element with five electrons in its valence shell we introduce free electrons into the silicon crystal. Giving it a negative charge. If we instead add a little bit of an element with 3 electrons in its valence shell we introduce extra holes looking for an electron to fill it. Giving it a positive charge. When we bring the positive (P) and the negative (N) materials together they from a P-N junction. The free electrons cross the junction to fill the nearby holes. Creating a neutrally charged depletion zone between the P and the N material. This is a diode. If we apply a forward biased voltage (positive battery terminal to the P side and the negative battery terminal to the N side) across this junction current will flow. Like charges repel each other. The negative charge pushes the free electrons on the N side of the junction towards the junction. And the positive charge pushes the holes on the P side of the junction towards the junction. Where they meet. With free electrons filling available holes causing current to flow. A reverse bias does the reverse. Pulls the holes and electrons away from the junction so they can’t combine and cause current to flow.
It takes energy to move an electron out of its ‘hole’. And when an electron combines with a hole it emits energy. Typically this energy is not in a visible wavelength so we see nothing. However, with the proper use of materials we can shift this wave length into the visible spectrum. So we can see light. Or photons. This is the principle behind the light emitting diode. Or LED. An electric current through a P-N junction causes electrons to leave their holes and then recombine with holes. And when they recombine they give off a photon in the visible spectrum of light. Which is what we see. A photocell basically works the other way. Instead of using voltage and current to create photons we use photons from the sun to create voltage and current.
A Solar Array that could Produce 12,000 Watts under Ideal Conditions may only Produce 2,400 Watts in Reality
When we use the sun to bump electrons free from their shells we call this the photovoltaic (PV) effect. This produces a small direct current (DC) at a low voltage. A PV cell (or solar cell) then is basically a battery when hit with sunlight. Electric power is the product of voltage and current. So a small DC current and a low voltage won’t power much. So like batteries in a flashlight we have to connect solar cells together to increase the available power. So we connect solar cells into modules and modules into arrays. Or what we commonly call solar panels. Small panels can power small loads. Like emergency telephones along the highway that are rarely used. To channel buoys that can charge a battery during the day to power a light at night. And, of course, the electronics on our spacecraft. Where PV cells are very useful as there are no utility lines that run into space.
These work well for small loads. Especially DC loads. But it gets a little complicated for AC loads. The kind we have in our homes. A typical 1,000 square foot home may have a 100 amp electric service at 240 volts. Let’s assume that at any given time there could be as much as half of that service (50 amps) in use at any one time. That’s 12,000 watts. Assuming a solar panel array generates about 10 watts per square foot that means this house would need approximately 1,200 square feet of solar panels (such as a 60 foot by 20 foot array or a 40 foot by 30 foot array). But it’s not quite that simple.
The sun doesn’t shine all of the time. The capacity factor (the percentage of actual power produced divided by the total possible it could produce under the ideal conditions) is only about 15-20%. Meaning that a 1,200 square foot solar array that could produce 12,000 watts under ideal conditions may only produce 2,400 watts (at a 20% capacity factor). Dividing this by 120 volts gives you 20 amps. Or approximately the size of a single circuit in your electrical panel. Which won’t power a lot. And it sure won’t turn on your air conditioner. Which means you’re probably not going to be able to disconnect from the electric grid by adding solar panels to your house. You may reduce the amount of electric power you buy from your utility but it will come at a pretty steep cost.
Solar Power Plants can be Costly to Build and Maintain even if the Fuel is Free
Everything in your house that uses electricity either plugs into a standard 120V electrical outlet, a special purpose 240V outlet (such as an electric stove) or is hard-wired to a 240V circuit (such as your central air conditioner). All of these circuits go back to your electrical panel. Which is wired to a 240V AC electrical service. A lot of electronic devices actually operate on DC power but even these still plug into an AC outlet. Inside these devices there is a power supply that converts the AC power into DC power. So you’ll need to convert all that DC power generated by solar panels into useable AC power with a converter. Which is costly. And reduces the efficiency of the solar panels. Because when you convert energy you always end up with less than you started with. The electronics in the converters will heat up and dissipate some of that generated electric power as heat. If you want to use any of this power when the sun isn’t shining you’ll need a battery to store that energy. Another costly device. Another place to lose some of that generated electric power. And something else to fail.
We typically build large scale solar power plants in the middle of nowhere so there is nothing to shade these solar panel arrays. From sun up to sun down they are in the sunlight. They even turn and track the sun as it rises overhead, travels across the sky and sets. To maximize the amount of sunlight hitting these panels. Of course the larger the installation the larger the maintenance. And the panels have to be clean. That means washing these arrays to keep them dirt and bird poop free. Some of the biggest plants in service today have about 200 MW of installed solar arrays. One of the largest is in India. Charanka Solar Park. When completed it will have 500 MW of PV arrays on approximately 7.7 square miles of land. With a generous capacity factor of 30% that comes to 150 MW. Or about 19 MW/square mile. The coal-fired Robert W. Scherer Electric Generating Plant in Georgia, on the other hand, generates 3,520 MW on approximately 18.75 square miles. At a capacity factor of about 90% for coal that comes to about 3,168 MW. Or about 169 MW/square mile. About 9 times more power generated per square mile of land used.
So you can see the reason why we use so much coal to generate our electric power. Because coal is a highly concentrated source of fuel. The energy it releases creates a lot of reliable electricity. Day or night. Summer or winter. A large coal-fired electric generating facility needs a lot of real estate but the plants themselves don’t. Unlike a solar plant. Where the only way to generate more power is to cover more land with PV solar panels. To generate, convert and store as much electric power as possible. All with electronic equipment full of semiconductors that don’t operate well in extreme temperatures (which is why our electronics have vents, heat sinks and cooling fans). So the ideal conditions to produce electricity are not the ideal conditions for the semiconductors making it all work. Causing performance and maintenance issues. Which makes these plants very costly. Even if the fuel is free.
Tags: AC, AC power, battery, capacity factor, Coal, converter, current, DC, DC power, diode, direct current, electric power, electricity, electronic, electrons, energy, free electrons, holes, LED, P-N junction, panel array, photocell, photon, photovoltaic effect, power, PV, PV cell, semiconductor, silicon, silicon atoms, silicon crystal, solar array, solar cell, solar panel, solar panel array, solar power, solar power plant, valence electrons, voltage
Week in Review
The developed nations are falling in love with East Africa. Why? Because they have oil literally oozing out of the ground. And enormous natural gas deposits are under the waters off Tanzania and Mozambique. The kind they measure using the word ‘trillion’. This energy bonanza is drawing the developed nations to East Africa to bring these resources to market. And into their economies (see Oil and gas are the new African queens by Emily Gosden posted 7/1/2012 on The Telegraph).
“In the space of a few years, East Africa has become a feeding ground for most of the world’s oil majors, which have sniffed our resources of oil and gas on a truly gargantuan scale,” wrote Malcolm Graham-Wood, oil analyst at VSA Capital, in a recent note. And in the world of oil and gas where, as he puts it, “if you find it, they will come”, those gargantuan reserves are the key.
“It’s been known there’s oil here for 100 years,” Laurie Hunter, chief executive of explorer Madagascar Oil says. “It actually seeps out on the surface in places.”
But with exploratory drilling consistently exceeding expectations, the geology of East Africa is proving to be even better than once thought.
FTSE 100 explorer Tullow Oil began drilling by Lake Albert in Uganda in 2006 – the first well there since 1938. It has drilled 45 wells to date; 43 of them have hit hydrocarbons. The company says it believes the Lake Albert rift basin is a “a major hydrocarbon province in its own right”, with resources as high as 1.1bn barrels. French oil major Total and Chinese CNOOC have paid $2.9bn to buy into Tullow’s stakes…
But while the oil discoveries look transformational – for all involved – it is gas that is causing the most excitement. In the balmy waters of the Indian Ocean, off the coasts of Tanzania and Mozambique, gas discoveries are estimated to stand at more than 100 trillion cubic feet (tcf). Potential resources are significantly higher. By way of context, the UK’s entire annual natural gas consumption in 2010 was 3.3tcf…
But it’s not just the geology that makes East Africa so exciting – it’s also the geography. “Conveniently,” Mr Graham-Wood notes, East Africa’s gas “faces the lucrative markets of India and the Far East and is now a truly valuable commodity”.
The gas will be cooled into liquefied natural gas (LNG) so it can be shipped to Asia. Gas consumption jumped 21.5pc in China and 11.6pc in Japan in 2011, according to BP data…
Exploiting the reserves in East Africa is not without its challenges, as Mr Joyner notes from a recent visit to Mozambique. “There are no roads and you have to fly everywhere on dodgy twin-props.”
China has been particularly busy in Africa. Building a lot of infrastructure. In an infrastructure-starved continent. Out of the goodness of their heart. Unlike the colonial powers of times past. And I’m sure it’s just coincidental that enormous natural gas reserves are located so close to China. Just begging to find their way into that Chinese economy. Where gas consumption has jumped 21.5% in 2011. No, I’m sure that hasn’t a thing to do with their interest in Africa. Even though they’re investing in the energy industry in Africa.
As the developed nations buy these resources it should bring money into the private economies of East Africa. Or create them if they don’t yet exist. Creating jobs. A middle class. And hopefully a stable society. Complete with all the middle class institutions and the rule of law. Raising the standard of living for all in East Africa. By using the revenue from their energy sales to build an infrastructure in an infrastructure-starved continent. Preferably one that favors their needs and not the Chinese. Or the other nations flocking to East Africa.
Tags: Africa, China, developed nations, east Africa, energy, Indian Ocean, infrastructure, infrastructure-starved continent, middle class, Mozambique, natural gas, oil, Tanzania, Uganda
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