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> Is energy a fundamentally different economic input? What is the relationship of energy to economic growth? I am particularly interested in this. My intuitio

> Is energy a fundamentally different economic input? What is the relationship of energy to economic growth? I am particularly interested in this. My intuition tells me that energy is special because it is the only thing that the laws of physics says cannot be recycled. And that, given enough energy, everything else can be.

FiatLuxDave 10y ago
Technically, it is entropy sinks that you mean, not energy. Energy is quite recyclable given a sufficient entropy sink.
- dredmorbius 10y ago
  Exergy is energy available for work. Entropy is the degree of disorder in a system. Emergy is source energy (which must be defined in a formal definition, e.g., typically solar emergy) which is bound up in a particular product or energy source.
dredmorbius 10y ago
There are various inputs to productive processes (economic or otherwise): time, labour, raw materials, capital, information, and energy. Possibly land space or area. Of these, time passes (whether you do something or not). Capital is generally not immediately consumed (you might consider enzymes in biological processes as similar). Information isn't consumed (though may decay with time). Raw materials are transformed but fundamentally continue to exist. The distinction is energy, and in particular energy derived from fuels rather than flows. The most-mined material on Earth is coal. Oil and gas follow closely. After these, it's sand, gravel, aggregate, and rock -- we never truly left the stone age, we just process our stone far more effectively. After processing iron ore, you're left with iron or steel, which can, at least theoretically, be recycled. Other materials operate similarly. Fuel for living beings (that is food) is part of a flux attached to solar power (and mineral cycling), which is renewed annually. Fuel-based energy isn't. Coal, oil, or gas, once burnt, won't re-accumulate until recharged, on scales of 1,000 to 1,000,000 or more times longer than their use-cycle (that is, we're using coal, oil, and gas 1,000 to 1,000,000 times faster than they were originally laid down). There's a wonderful paper exploring this, Jeffrey S. Dukes, "Burning Buried Sunshine" (2003), availble at stanford.edu, highly recommended. Vaclav Smil also gets into this dynamic, I in his book Making the Modern World, in which he excludes from consideration food and fuel as materials of the modern world (along with air and water): Exclusion of food and fuel is justified not only because these two large consumption categories have been traditionally studied in separation (resulting in a rich literature on achievements and prospects) but also because they simply are not sensu stricto materials, substances repeatedly used in their raw state or transformed into more or less durable finished products. Unlike raw biomaterials (wood, wool, cotton, leather, silk), metals, nonmetallic minerals, and nonrenewable organics (asphalt, lubricants, waxes, hydrocarbon feedstocks) foodstuffs and fuels are not used to build long-lasting structures and are not converted or incorporated into the still increasing array of ephemeral as well as durable industrial, transportation, and consumer items. Foods are rapidly metabolized to yield energy and nutrients for human growth and activity; fuels are rapidly oxidized (burned) to yield, directly and indirectly, various forms of useful energy (heat, motion, light): in neither case do they increase the material stock of modern societies.

FiatLuxDave 10y ago

Technically, it is entropy sinks that you mean, not energy. Energy is quite recyclable given a sufficient entropy sink.

dredmorbius 10y ago
Exergy is energy available for work. Entropy is the degree of disorder in a system. Emergy is source energy (which must be defined in a formal definition, e.g., typically solar emergy) which is bound up in a particular product or energy source.

dredmorbius 10y ago

There are various inputs to productive processes (economic or otherwise): time, labour, raw materials, capital, information, and energy. Possibly land space or area. Of these, time passes (whether you do something or not). Capital is generally not immediately consumed (you might consider enzymes in biological processes as similar). Information isn't consumed (though may decay with time). Raw materials are transformed but fundamentally continue to exist. The distinction is energy, and in particular energy derived from fuels rather than flows. The most-mined material on Earth is coal. Oil and gas follow closely. After these, it's sand, gravel, aggregate, and rock -- we never truly left the stone age, we just process our stone far more effectively. After processing iron ore, you're left with iron or steel, which can, at least theoretically, be recycled. Other materials operate similarly. Fuel for living beings (that is food) is part of a flux attached to solar power (and mineral cycling), which is renewed annually. Fuel-based energy isn't. Coal, oil, or gas, once burnt, won't re-accumulate until recharged, on scales of 1,000 to 1,000,000 or more times longer than their use-cycle (that is, we're using coal, oil, and gas 1,000 to 1,000,000 times faster than they were originally laid down). There's a wonderful paper exploring this, Jeffrey S. Dukes, "Burning Buried Sunshine" (2003), availble at stanford.edu, highly recommended. Vaclav Smil also gets into this dynamic, I in his book Making the Modern World, in which he excludes from consideration food and fuel as materials of the modern world (along with air and water): Exclusion of food and fuel is justified not only because these two large consumption categories have been traditionally studied in separation (resulting in a rich literature on achievements and prospects) but also because they simply are not sensu stricto materials, substances repeatedly used in their raw state or transformed into more or less durable finished products. Unlike raw biomaterials (wood, wool, cotton, leather, silk), metals, nonmetallic minerals, and nonrenewable organics (asphalt, lubricants, waxes, hydrocarbon feedstocks) foodstuffs and fuels are not used to build long-lasting structures and are not converted or incorporated into the still increasing array of ephemeral as well as durable industrial, transportation, and consumer items. Foods are rapidly metabolized to yield energy and nutrients for human growth and activity; fuels are rapidly oxidized (burned) to yield, directly and indirectly, various forms of useful energy (heat, motion, light): in neither case do they increase the material stock of modern societies.