1/11/19
The way different human societies live is very
fundamentally based on energy
we think of economies in terms of money, but energy is more
fundamental
"Energy is the only universal currency"
- energy/matter are there and you can use them
for anything if you have the technology
- energy is the most valuable thing, you need it
to do everything
- how do you get enough food, by using energy
on the first level, more developed
societies use more energy--using more energy (via technology)
gives us easier lives
BUT that depends on how wastefully we use energy
and how efficient are the particular technologies we use
Determinism:
- does technology progress on an
inevitable path
- do we inevitably progress to
the most efficient way to do things
- is the wheel invented or
discovered
- but society decides what is
best
- so society determines the
direction of technology
- does technology determine
society
- no-we make choices about how
we use technology
consider as fundamental steps in
history changing prime movers and fuel bases
laws of thermodynamics--usable energy
units:
- measures of energy: calorie, btu, joule (note
that what we call a calorie for food is actually a
kilocalorie)
- power is rate of energy flow, eg. horsepower,
watt
- 8000 kilocalories of food a day is about 90
watts
- a small car delivers about 50 kilowatts
- energy density--amount of energy (eg.
calories) for a given mass (weight)
- efficiency of energy conversion (also called
energy return)
- energy intensity: whether an industry or
activity requires a lot of energy compared to others
- but note that how cheap energy is and how
easily transportable makes more difference than efficiency or
intensity
fun fact: Joule defined one horsepower as more
than what an average horse at the time could to do make his
engines look good
Jevons paradox: new technology improves efficiency
but instead of using less of that resource we use more (eg. our
cars get better fuel efficiency (miles per gallon) but instead of
using less gasoline we use more because now we drive more miles)
energy return: in agriculture how much energy do you expend to
grow the crop and then how much usable energy do you get out of
the crop
different from yield: if you plant 10 seeds do the plants you grow
yield 200 seeds?
"Smil recognized that energy starts big: the location of the
planet leading to life, the atmosphere providing rain to allow for
plants to grow, and the ground itself where organisms can live.
Yet Smil also alludes to the idea that how civilization
uses energy starts small and is an individual or societal
decision."