AdamB wrote:sjn wrote:It doesn't make sense to compare apples with trees.
Neither does it make sense to make distinctions without difference.
The difference actually in where the boundaries are drawn. It's a critical point. An energy carrier implies that the energy has gone through at least one transformation from the boundary source. Entropy has already increased.
sjn wrote: The point of the analysis is to perform it on the "full system", if you draw the boundary around yourself and your house you are not measuring the net energy from a given source through the economic system. Good luck running your generator when you run out of gasoline without enlarging your boundaries!
I didn't draw a boundary around anything. Only demonstrated that power generation is power generation, and the type or size of the energy involved to make the power might be completely meaningless, my requirements being for POWER generation, not the energy required to generate it.
You did, even if only implicitly. If gasoline is the source, you've already drawn the boundary such that the processes to create the gasoline are outside. So it might be meaningless, you can measure the efficiency of your process from your energy source, but if you're trying to determine the exergy and increase in entropy from the extraction of petroleum to your end use, then it is not.
sjn wrote:That doesn't mean the boundary should encompass the Sun, I think it's quite obvious that the Sun is outside the economic system, as are the micro-organisms that died to lay down the source of hydrocarbons in the gasoline!
It "might not mean", but there is no way you can discuss energy available to humanity and NOT discuss the fraction of the 64 million watts per square meter it generates that enters and effects our atmosphere, climate systems, and power generation systems. Our world is not a closed system when it comes to energy, we both accept inbound energy, and radiate it outward.
Sunlight is not the Sun. Sunlight enters the Earth system, thus it's an energy source from the Earth System boundary, the Sun does not. There's also an imbalance between incoming and outgoing radiation, but that's out of scope for this topic.
sjn wrote: But the processes involved, in an attempt to quantify how much exergy remains at the end of the process within established boundaries of the analysis. The utility of the (petrochemical product) gasoline is very much a function of the net energy from the petroleum production system. A direct comparison would be to "gasoline" or similar liquid fuel synthesised through a process powered by sunlight.
There is no question that the utility of a BTU of gasoline is worth more than a BTU of sunlight. We use economics to quantify that utility. However, you are now wiggling terribly hard, and are wrong in your claim that one liquid fuel can only be compared to another.
You are absolutely right, and I didn't mean only liquid fuels can be compared to each other, it was a misleading and poor example. I was trying to make the point that the net energy from extracting and refining crude oil (energy source) into gasoline (energy carrier) and using it to power a car is significantly higher than the net energy from an equivalent process converting sunlight (energy source) into a liquid fuel and using that to power a car. Your following example is actually a result of that.
The wife requires approximately 2.5 kWh of power to do the work necessary to get to and from her job each day. It is IRRELEVANT to her where that power comes from, and she has in fact replaced her liquid fuel use not with another liquid fuel, but electrical power from solar panels and natural gas fired grid power. Not a liquid fuel in sight.
This is actually a much better comparison and demonstrates a
process from sunlight (energy source) with much higher net energy return for the same end result as my example above. The entropy generation is much lower because there is less complexity so therefore fewer transformations.
So no, I was specific earlier about why you were making a distinction without a difference, as you have here by making up faux rules of what is comparable and what is not.
Feel free to explain your concept, but don't confuse energy or power, they are neither interchangable or synonymous.
But energy and work is. I know quite well what power is: Power=Work/time
So it's the rate of doing work, or in practical terms, it allows you to determine whether you can you get energy fast enough to run your process. An important consideration with solar panels and why your wife uses batteries rather than directly using panels on the roof of her car.
You started off this conversation saying net ENERGY, and I started off by talking about the things of importance we DERIVE from energy (not even specific to fossil fuels), the things of value. This IS a distinction with a difference, and one that many net energy people trip over because they don't understand the difference.
sjn wrote:As far as I understand, Economic Theory fundamentally assumes the economy is an equilibrium system. It's also not based on any physical laws or scientific principles. Energy is accounted for as a commodity, rather than the necessary prerequisite to perform work.
Of course energy is a prerequisite for work. But NOT substituting only liquid fuels for other liquid fuels. And I really am not about to define economic theory in a sentence that you want to relate to what appears to be thermodynamics, because they are not the same thing. Economists is a social science, basically it ATTEMPTS to describe 1) the aggregate behavior of many individual decisions when subjected to certain stimuli or 2) the individual behavior of a human when subjected to certain stimuli.
And for the record, empirical observations are themselves fundamental to forming a scientific hypothesis, and how many discoveries have been made. Including those in non-social sciences, geology, enginering, medicine, just about every one I can think of. But no, it isn't based on the kind of first order principles as physics. And it doesn't need to be.
It generally does need to be explained
by, or in terms of though. Behavioural Science for example attempts to explain its discoveries through the principles of Cognitive Neuroscience. Geology, Physics and Chemistry. Engineering, through Physics. Medicine though Biology, Molecular Biology, Chemistry, Biophysics etc.
Economics is not a Social Science. sjn wrote:The local flea market is a subset of a larger economy. But you clearly get what I was saying, the term I was using was "Economy" at the aggregate globalised level. If we didn't have a Global Economy then it would make more sense to treat each economy as an separate entity, since the properties of each could differ quite considerably.
Can you please couch your terms, in the future, as to whether or not you are discussing micro or macro economic theory. You are correct, there are differences, and a concept in one might not apply to another. For example, your globalize Economy is subject to decisions on the part of regulators or politicians that might have NOTHING to do with normal economic behavior, but generate economic consequences. Think...Venezuela.
And little Economies also interact with their larger counterparts...think about crude oil exports. Each larger entity in economics can be broken down until we arrive right back at the local flea market, and a buyer and seller debating the price for a thing.
In
Systems Science more broadly, pretty much all systems are embedded or have embedded in them other systems. The approach is holistic.