Understanding energy, an introduction to being green 101

[my54ford]

Good post...I would suggest any study on energy, energy density, etc. should be coupled with a study of how energy (electrical)is provided here in the US. The instantaneous response to demand changes on a Nation wide basis without deviation from 60 Hz.

[mshultz]

I think this would be a good course, especially with the right lab exercises to accompany it. I am thinking in terms of comparing human powered generators to gas and electric generators, and measuring the output of solar and wind power.

One good experiment would be mowing three similar lawns with a gas mower, a battery mower and a human powered reel mower. Measure the energy consumed, the area mowed, and the amount of time it takes.

I would avoid preaching in the course; let the students see for themselves how alternative energy sources compare to conventional electricity and gasoline.

[Zot]

Thanks for the replies ... I'll try to continue and see if this can be helpful.

There are problems with energy, it comes in different forms, and isn't always in a form we would like. The example of the Big Mac vs a gallon of gasoline as an example. Converting the potential energy of one to the other is possible, but sometimes not entirely useful. For example we can't digest gasoline, it's toxic, and may eat flesh, plus be carcinogenic. Similarly a car can't process a Big Mac as a fuel source, it has no capability to process proteins, carbohydrates or fat as we do.

Prior to fossil fuels, most transit was via foot, beast of burden, or ship (often sail). The energy required to feed a human, horse, camel, or sail a ship came from the sun for the most part. We had some small use of metals, but no electricity in any quantity, no modern forms of light, transport, or electric / electronic devices.

As we developed the scientific method, and had math to begin to understand and describe our universe, many technologies began to be developed. Exploitation of fossil fuels, only works, due to our understanding of how to use these fuels. Certainly oil and coal were found prior to our understanding how to use them to create power, but we required as a species an understanding to help us utilize these latent energy sources.

At the time of their discovery, and through much of modern history, there was a constant argument about how much fuel there was on earth, or how long fuel of any type would last. Concerns also about pollution grew, as the scale became larger, and as populations increased.

We have the luxury to worry about fuels in the first world today. This is mostly westernized countries, who enjoy a very high standard of living, which is entirely dependent upon inexpensive energy. Much of the world does not have power, does not have internet, does not have access to many things we take for granted. This disparity is partly cultural, partly a matter of history, but also a matter of exploitation. Cheap energy has been diverted to the wealthy nations of the world. While those in nations without abundant energy resources, or who suffer with a culture which is no well educated and first world capable, suffer greatly.

To impose green requirements we find helpful in the first world, may be inappropriate to people who are starving and dying of very curable problems. It's like discussing the sale at a local mall while a house is burning, the folks in the house don't care.

Related to energy, and energy use, is electricity. If there is a lowest common denominator of energy it would be measured in fossil fuels. Of the types of power created, one of the most useful to humans is electric power. With electric power we can convert motion to electricity, and electricity to motion. Direct sunlight can be converted to energy through a photo voltaic process.

A problem with electricity is the need to provide support for a large load all day every day continuously. Without reliable power, modern life would suffer greatly. Our refineries, cars, trains, and communications systems all require electric power to operate. A car can't get gas, if there is no power in a gas station pump, and a gas station can't get gasoline without a powered refinery. Oil and electricity are necessary for modern life, but while electricity can live without oil, oil can't, at least not at the quantity we require.

As mentioned in my first post, a gallon of gasoline has a lot of power. According to Wikipedia a Volt has about 10 KWh of electric power storage in it's battery. Chevrolet Volt - Wikipedia, the free encyclopedia as was discussed a gallon of gasoline contains 31,000C (large calories, kCal) 10 KWh represents about 8,600C (kCal) of power.

This means a GM volt car, has something slightly less than a third of a gallon of gas equivalent power available as electric power, if we rounded, it would be close to a quarter gallon of gas.

Electric engines are far more energy efficient than internal combustion engines, however, a gasoline powered car will drive further, and deliver out of some of it's waste, tremendous heat in winter, reliable air conditioning in summer, and electric power to operate on vehicle lights, electronics, and anything else you can think of.

The largest problem for the GM Volt, is energy storage, specifically battery technology. Currently this is the largest limiting factor when trying to consider or build an electric vehicle.

A second problem concerns green folks, a Volt, will still use energy. It's energy source may not be clean or green. We displace the energy production out of sight. That doesn't mean the Volt has no green load when running on electricity, it means the load is displaced elsewhere.

If you wonder why the Volt can be charged up so cheaply, it's due to it's very limited ability to carry energy. This is a false savings. It's greenness is entirely dependent on the source of electricity to the grid that feeds it (the entire grid, buying green energy doesn't make the power in your car green, you can't buy an indulgence from physics, as green people we must understand electron flow in power cables doesn't respect any source, we can't quantize push from one source vs another). Any attempt to claim savings due to buying green energy, is for the most part a self delusion. The energy we take off our grid, is pushed on from diverse sources, and no single souce can specify a target home, meter or vehicle.

***

To the readers, my apology for being slow to post this, I've been a bit ill.

To Chemistry_Guy I am old, and a scientist, but not a physicist (though my son teaches physics at a University). Regardless use of scientific terminology would likely turn off readers, and I have no clue how to write any decent math on this forum regardless with whatever HTML is permitted. An introduction to calculus isn't likely to be helpful here. Pick up any slack you may wish. I'm trying to introduce some of the concepts which guide me while seeking to be greener.

[Chemistry_Guy]

I guess my first comment would be that we spend a whole lot of our energy converting one form of potential energy to another. In the case of the big mac, for example, we spend energy to water and fertilize the crops that we spend energy to harvest, and then most of the potential energy in the plant material is lost as heat as a part of the cow's metabolism. We then slaughter the cow, transport it a long distance, spend energy to keep it refrigerated, before spending energy to cook and serve it. There are countless other inefficiencies in the process as well. Therefore, it is not an apples to apples comparison when comparing foods vs. fuels.

Similar inefficiencies are seen in transportation, home heating and cooling, computing, and manufacturing. I have to go home now, but I'll be back later.

[OpenD]

Originally Posted by Zot

This means a GM volt car, has something slightly less than a third of a gallon of gas equivalent power available as electric power, if we rounded, it would be close to a quarter gallon of gas.

I'm not even going to check your math on this, because I'm not sure what your point is, nor why you think it matters. The quarter-gallon equivalent, if that is what it is, can drive the car 38 miles. Then it switches over to the gas engine and drives another 380 miles. So the Volt is not a good example for your discussion, because it's not really an electric vehicle like the Tesla is. It's a hybrid.

Electric engines are far more energy efficient than internal combustion engines, however, a gasoline powered car will drive further, and deliver out of some of it's waste, tremendous heat in winter, reliable air conditioning in summer, and electric power to operate on vehicle lights, electronics, and anything else you can think of.

Gasoline has a high energy density. Yes, we know that. That's why it has been such a popular fuel source for motor vehicles for so long, and why it is hard to replace. But we have no choice. We must replace it before we wreck the ecology of the planet we all depend on for our lives due to the pollution it emits.

The largest problem for the GM Volt, is energy storage, specifically battery technology. Currently this is the largest limiting factor when trying to consider or build an electric vehicle.

No question, but there are several promising new battery technologies which could be game changers for EV cars within a fairly short time.

A second problem concerns green folks, a Volt, will still use energy. It's energy source may not be clean or green. We displace the energy production out of sight. That doesn't mean the Volt has no green load when running on electricity, it means the load is displaced elsewhere.

If we charge an EV from a non-polluting renewable energy source... be it hydro power, solar power, wind power, geothermal power, etc... then the EV can be completely green in operation. And this is obviously the goal many, many people are working towards. But even if the EV is charged by electricity from a polluting fossil fuel generating plant, it is a better choice ecologically than a car with a gasoline engine in many scenarios, because a large power plant is far, far more economical to operate and uses far less energy than an equivalent number of cars, as well as being far more efficient at trapping pollutants. And for extremely sensitive environments like Southern California, it makes sense to... as the metaphor goes... have a single large tailpipe outside the big cities that can replace a million small tailpipes within the city.

If you wonder why the Volt can be charged up so cheaply, it's due to it's very limited ability to carry energy. This is a false savings.

I find this to be an odd statement, because it's almost as though you don't realize the Volt has a gasoline engine in it. And the Volt's range on electric charge alone is only 38 miles, so the cost of the electricity to give it a full charge is very small.

You're going down the wrong path with this, as far as I'm concerned.

It's greenness is entirely dependent on the source of electricity to the grid that feeds it (the entire grid, buying green energy doesn't make the power in your car green, you can't buy an indulgence from physics, as green people we must understand electron flow in power cables doesn't respect any source, we can't quantize push from one source vs another).

Sure, that's obvious. At the present we're in a transitional phase, because we can't just shut down fossil fuel generation now, or any time soon. So some of our electricity continues to be generated from traditional sources, and some from newer cleaner sources, and the net outcome is an improvement over using pure fossil fuel power alone.

Any attempt to claim savings due to buying green energy, is for the most part a self delusion.

Oh, my. I'm afraid you really don't understand this. Nobody is claiming a cost saving because they are charging their EVs with power purchased from Green energy sources. People are reporting that their cost per mile driving on electric battery operation is half what it would be on gasoline because they are tracking their actual driving costs. This is real. There's absolutely no question about it. Put $10 worth of electricity into a Tesla S and you'll be able to drive twice as far as a traditional ICE car with $10 worth of gas in it.

The energy we take off our grid, is pushed on from diverse sources, and no single souce can specify a target home, meter or vehicle.

Of course not, and I don't know anybody who thinks that. People who live in states where they are allowed to choose their electricity provider can often choose a "green" provider that sources wind or solar energy, but currently they usually pay a bit of a premium to do so, in order to support the renewable energy effort.

Even those people can save money with electric cars, because even at higher rates than plain vanilla electricity, it's still cheaper per mile than gas is.

But there is no pretense or expectation that the kilowatts they use are the same killowatts put into the system by their provider. It's just that in terms of cost and billing, electricity is fungible... put it in here, take it out there, it balances out, even if the electrons involved never actually meet.

[my54ford]

Originally Posted by OpenD

I'm not even going to check your math on this, because I'm not sure what your point is, nor why you think it matters. The quarter-gallon equivalent, if that is what it is, can drive the car 38 miles. Then it switches over to the gas engine and drives another 380 miles. So the Volt is not a good example for your discussion, because it's not really an electric vehicle like the Tesla is. It's a hybrid.



Gasoline has a high energy density. Yes, we know that. That's why it has been such a popular fuel source for motor vehicles for so long, and why it is hard to replace. But we have no choice. We must replace it before we wreck the ecology of the planet we all depend on for our lives due to the pollution it emits.



No question, but there are several promising new battery technologies which could be game changers for EV cars within a fairly short time.



If we charge an EV from a non-polluting renewable energy source... be it hydro power, solar power, wind power, geothermal power, etc... then the EV can be completely green in operation. And this is obviously the goal many, many people are working towards. But even if the EV is charged by electricity from a polluting fossil fuel generating plant, it is a better choice ecologically than a car with a gasoline engine in many scenarios, because a large power plant is far, far more economical to operate and uses far less energy than an equivalent number of cars, as well as being far more efficient at trapping pollutants. And for extremely sensitive environments like Southern California, it makes sense to... as the metaphor goes... have a single large tailpipe outside the big cities that can replace a million small tailpipes within the city.



I find this to be an odd statement, because it's almost as though you don't realize the Volt has a gasoline engine in it. And the Volt's range on electric charge alone is only 38 miles, so the cost of the electricity to give it a full charge is very small.

You're going down the wrong path with this, as far as I'm concerned.



Sure, that's obvious. At the present we're in a transitional phase, because we can't just shut down fossil fuel generation now, or any time soon. So some of our electricity continues to be generated from traditional sources, and some from newer cleaner sources, and the net outcome is an improvement over using pure fossil fuel power alone.



Oh, my. I'm afraid you really don't understand this. Nobody is claiming a cost saving because they are charging their EVs with power purchased from Green energy sources. People are reporting that their cost per mile driving on electric battery operation is half what it would be on gasoline because they are tracking their actual driving costs. This is real. There's absolutely no question about it. Put $10 worth of electricity into a Tesla S and you'll be able to drive twice as far as a traditional ICE car with $10 worth of gas in it.



Of course not, and I don't know anybody who thinks that. People who live in states where they are allowed to choose their electricity provider can often choose a "green" provider that sources wind or solar energy, but currently they usually pay a bit of a premium to do so, in order to support the renewable energy effort.

Even those people can save money with electric cars, because even at higher rates than plain vanilla electricity, it's still cheaper per mile than gas is.

But there is no pretense or expectation that the kilowatts they use are the same killowatts put into the system by their provider. It's just that in terms of cost and billing, electricity is fungible... put it in here, take it out there, it balances out, even if the electrons involved never actually meet.

Really? There is a regular poster here that will swear the green power he pays for which is generated 100's of miles away is the exact same power delivered to his house. Never ,mind that big nuker setting between him and the wind farm....